Ambroise Gardeil, Evolution and the Principles of St. Thomas

The present translation is an extract of the 7th and 8th installments in a longer series of articles in Revue Thomiste dedicated to the question of various theories of evolution and their relationship to Thomistic metaphysics.¹ It is in fact quite remarkable that Gardeil undertook this task so early in the journal's life, from its very first issue. I have chosen these two installments because I wanted to spend a little extra time thinking about what he says regarding habitus and its application to the metaphysics that would need to be involved in a sound theory of evolution. At present, I am merely presenting the text as it stands in draft. Certain scientific points in the closing section are dated, and yet the overall metaphysical proposal remains interesting. I do think he is correct to see that careful philosophical reflection on the nature of habitus can provide insights for articulating the causality necessary if there is to be a diachronic formal elevation of prime matter. If nothing else, the reader can benefit from what he says about habitus.

Fr. Gardeil's Text

“Nature imitates itself. A seed sown in the ground is productive. A principle, sown in a good mind, is likewise productive... Everything is fashioned, produced, and guided by the same Master: the root, the branch, the fruits; the principles and the consequences.” (Pascal. Pensées.)

Powerful minds are quite ready to develop an entire system using a very simple idea, often an image. Constantly, they have it at hand as their guide and point of reference. The reader or listener is unaware of these sometimes fragile foundations. Pascal alone seems to have seen clearly into Descartes’ system: “To put it broadly: it is fashioned through figure and movement, for that is true. But to specify what they are and construct the machine, that is ridiculous. For it is useless, uncertain, and tedious” (Pensées). He alone, in a single glance, unraveled the underlying idea—perhaps unconscious, but certainly fundamental—that fashioned the Cartesian mechanism: “I cannot forgive Descartes; throughout his entire philosophy, he would have liked to find a way to do away with God, but he could not help but give Him a nudge to set the world in motion. After that, he has no further use for God.”²

This project of banishing God from the world system is also implicit in the thought of our modern evolutionists. Unlike Descartes, they admit it when necessary; but, as a rule, they conceal it, like Descartes, under an inoffensive framework, constructed with the aid of a very simple notion accepted in science. Haeckel, for example, copies a well fashioned machine; Spencer complicates this machine with the internal forces of the dynamists; Hartmann posits an organism that develops in fits and starts under the impulse of living and unconscious energies; without rejecting these viewpoints, Monsieur Fouillée models his idea of evolution on a kind of psychological organization.

In the first part of this study, we identified St. Thomas’s principles concerning causality, enabling us to rationally critique these systems. “Any of the four would serve well.” Fouillée understands this. He does not exclude the mechanical notion; rather, he supplements it with a psychological organism. In this way, he embraces the whole reality, whereas the previous systems systematically neglected the psychological element. Moreover, he does not hesitate to explain the physical through the psychological. He even goes too far, since he attributes consciousness to the most minute physical elements. In any case, he has charted a new path, where one does not immediately encounter a rational impossibility. Currently, in France, several eminent minds are pursuing parallel paths. I refer—despite their differing viewpoints—to Théodule Ribot and Émile Boutroux.³ It seems likely that there will be agreement on the ground where reconciliation must take place. Some are already boldly indicating this by announcing that evolutionary theory will be psychological or else it will never come into existence.

This progress in evolutionary philosophy brings us closer to Aristotle and Saint Thomas, who never held that the world was a mere machine, like Spencer, nor that it is a kind of living being, like Hartmann. From time immemorial, we have professed, following these great minds, that the world had a “psychological structure”—only, we expressed it in a different way and with different words. What, in fact, are substantial and accidental forms, their appetites, their activities, etc.—these elements of the constitution and functioning of the Universe according to the Thomists—if not mental elements, kinds of rudimentary ideas or volitions, not truly conscious, yet analogous to those of beings that have a soul, in a word, “psychological.” And these elements have among themselves, according to the Thomists themselves, those same relations of origin, causal subordination, and ideal hierarchy that our modern psychologists recognize in states of consciousness. Thus, the mental and the real appear to us as mirrors reflecting the same image.

This final part of our study is dedicated to the claim that the psychological domain lends itself to the desired reconciliation between the principles of Saint Thomas and evolutionary theory. We will take this up in two sections: one psychological, the other metaphysical. In the first, we will determine the meaning and role of evolution in St. Thomas’s psychological account. In the second, we will discuss the application of psychological evolution, as understood by Saint Thomas, to the problem of the world’s origin.

I. Psychology

A. In Search of a Psychological Evolution

There are several different ways of understanding the nature of psychological development. Idealists do not conceive of it in the same way as positivists, and Aristotle’s psychology naturally has its own distinctive views as well.

1. For idealists, psychological development seems to consist in the various aspects in which objective “presentation” stands in opposition either to the reflexive intuition of the thinking subject (Kant) or to experience itself considered from its subjective side (Neo-Kantians).

In the first case, the thinking subject is outside of evolution. Evolution would be entirely objective. However, since the object is contained within the subject, it can, in this sense, be called psychological. In the second case, psychological reality itself—experience—evolves according to “objective presentations.” In both cases, there is no physical evolution in the true, objective sense of the word.

Such an analysis of psychology and its development is unsuitable for our purposes. Not only is it intrinsically false.⁴ Moreover, it is useless for the solution of the present problem. By trivializing the given, it suppresses it. And we are seeking a reconciliation.

2. Positivists and materialist philosophers in general view evolution as a self-propelled ascent of prime matter to the higher levels of being. The conception articulated by the proponents of immanent evolutionism, such as Hartmann and Fouillée, boils down to this. This view is certainly not purely materialist, since it places at the origin of evolution a rudimentary germ of life or consciousness. Nonetheless, both systems share the common feature of claiming that the production of all degrees of being, including the psychological degree, is ultimately attributed to a cause belonging to the lowest order of things. Tissues, organs, faculties, hereditary habits, acquired virtues or vices—everything is created by some sort of rising tide, either by virtue of an automatic mechanism reminiscent of Locke’s statue apparatus,⁵ or through the efficacy of an internal law of development.

We need only briefly comment on this system. It contains an experiential element—the one studied by men like Darwin, Romanes, Pérez, Ribot, and Preyer—which is infinitely valuable to psychology. But its metaphysical aspect is highly hypothetical. I mean that its theories do not express anything that is intellectually necessary. They are purely fabulous, and for the most part as unreasonable as they are poorly written. Therefore, we prefer the members of this school who remain within the realm of observation, such as Ribot and Preyer, to those who theorize amid the fog. However, their psychology is far from complete. The field has barely been cleared. Moreover, one might think that they lack, to some extent, the necessary rational tools. Therefore, we cannot expect to draw from this group of theorists a doctrine capable of serving as the basis for a psychological theory of evolution.

3. In Aristotle, psychological evolution—if I may retain that term—can have only a limited field for application. As is the case for the Kantians, the soul is beyond evolution: it is the intangible foundation for such evolution. Unlike the claims made by the philosophers of the previous group, the powers of the soul themselves are not the object and end of evolution. They emanate directly from the essence of the soul. What remains is the realm of psychological habits, whose effects, as Boutroux perceptively notes, “bear a certain resemblance to mechanical causality. At the starting point lies, at least in certain cases, the activity of the mind; actions are related to thought as to their generative cause. Little by little, they detach themselves from thought and, in a sense, push one another forward.”⁶ At this point, when actions no longer originate in a present thought, while continuing to be exercised according to the determination of that thought, habit exists. We thus have, in the genesis of habitus, a most appropriate field of observation. We are no longer dealing with the mysterious metempsychosis, which in the previous system led us from the marine polyp to that “polyp of images” which, according to Taine, is our brain. This is an everyday fact, laid bare in the light of observation, which we call education, character formation, the acquisition of habits, etc.

It is on this solid foundation that, together with the authors of the second book of the Nicomachean Ethics and q. 51 of Summa theologiae I-II, we shall base our search for the laws and rational conditions of psychological evolution. Undoubtedly, our field of investigation is limited: it is the only one, we shall reply, in which evolution is observable. Everything else is hypothetical. It alone is capable of enabling us to grasp in real time how an idea comes to take hold, become fixed in matter, take shape, and be added to what is already fixed, raising the scale of beings by one degree. Indeed, is this not the spectacle we behold as habits are formed? And what is this spectacle, if not what we have come to call evolution?

B. Habit in Thomist Psychology

Therefore, what, exactly, is a habit? To explain it, we must delve into some topics that are tangential to our main subject but necessary for those readers who may not have sufficient acquaintance with Thomistic psychology. We will endeavor to gather these brief concepts around the two points which are essential for understanding the role that evolution can play in the development of habits: the realism of our psychology; its hierarchical nature.

1. General Characteristic of Thomistic Psychology: Realism.

All the elements of the psychological organism conceived by Aristotle present themselves as real forms or entities. This vigorous realism is of little use to minds shaped by the unintelligent materialism or fearful spiritualism of our own day. It is a settled affair: there are no real distinctions except the actual, quantitative separations ascertained by our senses. If the mind protests that it distinguishes, within the self for example, faculties that certainly appear to be distinct realities, it is answered that these are merely modalities, a kind of vaporous phantoms that vanish and, at the first light of psychological examination, are reabsorbed into what is truly substantial.⁷

While the objectivists are thus kept on a tight leash, the Neo-Kantians have all the rights. Let them be, let them pass: such is the faculty’s order regarding them. They, naturally, take full advantage of the privilege. In their works and lectures, there are nothing but distinctions—of aspects of the subject, the object, the idea, experience, and so on—a whole museum of logical entities carefully pinned, labeled, and classified. Bourgeois philosophy can rest easy. By allowing the logical needs of the mind to furnish the utopian land of subjectivism, it has made a compromise; it has saved the Object! The latter will be left to mediocre doctrines, enemies of excess and of any profound intellectual analysis. And this superficial philosophy will be pompously christened with the popular name of the philosophy of Common Sense (Bon Sens).

Alongside Aristotle and Saint Thomas, however, we demand that objectivist philosophy be granted its share of the privilege enjoyed by Kantians. We demand this by virtue of the very rights of the mind, which is made to carry its work through to the very end, down to the intellectual bedrock, to those depths where clear ideas and self-evident truths reside. The objective value we recognize in these ideas cannot serve as an a priori reason to reject our demand. The Kantians have never apodictically demonstrated that our intellectual instrumentation is, by its very nature, condemned to subjectivity. Aristotle, Saint Thomas, and their disciples, by contrast, demonstrate very well that the idea as presented to us by internal observation (a process we share with the Kantians) is a real and definite expression of something which, without contradiction, cannot be anything but real, nor admit of any definition other than that which the idea itself contains.⁸ And on this first and obvious insight, which also applies to the sensible realm, we base an entire, highly detailed system of knowledge which leaves no objective element unexplained, and which is, moreover, quite coherent and free from intellectual contradiction. Under the same conditions, we likewise develop a system of psychological action. Both systems do not fail to account for every element that engages the mind and, despite this, are free from intellectual contradiction. This is quite unique. However, it is acknowledged even by Kantians themselves, who criticize it only for its point of departure. For us, this criticism amounts to approval: the rational unity of a system is the best crosscheck for the value of its principles.

Now, habit is naturally defined within what we have termed “a system of psychological action.” We now know what conception to expect. Habit will be a psychological entity in the same way as so many others are: the soul, faculties, and actions, which are the elements of Aristotelian psychology. They are real, simple forms, and thus objects of the clearest apperception for the mind that perceives them—whether within itself, if they are of the intellectual order, or in the images where the outline of the essence of psychological realities, as well as material things, is depicted, refined yet always identical in form. Forms distinct to the mind’s eye: the soul first, the organizing unity of the body and the faculties. Then, there are the distinct powers of the soul, for the soul, as a simple act, is necessarily entirely in act [as the substantial form of the being in question]. It cannot be directly and immediately the causative principle of intermittent operations such as psychological actions. There must be a principle that “slumbers” (this is Aristotle’s own expression in Book I of On the Soul), namely, the powers of the soul. The concept of operative power (and consequently its reality) is an objectively logical consequence of the objective intermittence of psychological operations. Their diversity is necessitated by the diversity of these very operations. The powers are suited to serve as intermediaries between the one, active soul of the self and the multiple, quiescent actions: they draw their vital reality from the soul, and through the potential reality proper to them, they become the specific and intermittent principles of formally distinct activities.

The conception of habit as an entity is as foreign to modern psychology as it is central to Aristotle’s. Words, as signs of things, serve as proof of this. According to him, the term “habit” in the sense we understand it—namely, a customary way of acting—lacks precision. This defined way of being requires a defined entity that serves as its cause, just as laws require a being that serves as their principle. Just as laws, for Aristotle, must originate from a form, so too does habit—which seems indeed to be a psychological law—find its raison d’être in ἐξις (habitus in St. Thomas). This word signifies something possessed, owned, a possession, if you will, and this meaning, when compared to our modern word habitudo—that is, habit in the sense of a law or customary relationship—captures the characteristic of the two systems better than a long discourse. Our modern system confines itself to the apparent phenomenon: it does not reason it out. Aristotle goes back to the cause: he notes in the very word that designates immobility and definitive acquisition, the presence of a stable form—in short, the distinctive trait of habit, which is a certain permanence of form in the repetition of distinct operations.

As we shall soon see, habits arise from the mutual action and reaction of the powers of the soul—for example of the intellect on the will. Therefore, we need to go into some details regarding these powers, their nature, and their organization within the thinking subject.

2. Specific Characteristic of Thomistic Psychology: The Causal Subordination of its Elements

The powers of the soul must not be considered in isolation. They are united with the soul, which is their common foundation. The soul acts through them. When they act, they form a single operative principle together with the soul. And, likewise, they act solely for the soul: the operation of the powers ultimately aims at the benefit of their lifegiving root: entitate simplex, virtualitate quasi infinita.

The powers of the soul must be regarded as forming a coherent and hierarchically interconnected system of movers and moved [powers], the latter in turn serving as movers by virtue of the impulse they have received. These movers in no way hinder the spontaneity of the actions proper to each of the subordinate powers. The activity of the dominant power blends harmoniously with the activity of the subordinate power. For example: acts of will that proceed from the loftier intellectual power and are, as it were, imbued with this very elevation—or as Aristotle would have said, “informed” rather than “imbued.”

The powers—at least those ordered toward psychological life, namely knowledge and appetite—are superimposed in two levels. On the lower level, there is perception: first as a particular sensation, then as a sensation compared in the common sense, then as an image, a memory, and finally as experience—in the respective faculties, always sensory, of the imagination, of (sensory) memory, and of the estimative or appreciative sense of particulars. Sensory perception corresponds, as a kind of reflex, to the sensory appetitive order, whose eleven passions are coordinated along two lines (of five and six each): the line of forceful passions governed by anger, and the line of gentle passions governed by love. In short, we designate these two groups by the established terms irascible and concupiscible.⁹ From its higher level, the will—an appetite resulting from rational judgments—governs the world of the sense appetites. This intervention is both efficient- and formal-causal in nature: efficient by the very nature of the will, and formal by the nature of the intellect, of which the will is the instrument. The finger that moves in a specific direction receives from the nervous impulse not only the motor impulse but also the idea of its direction, which must be drawn from a cognitive faculty.

The complete hierarchy of psychological faculties unfolds in the following order of dependence: intellect, will, concupiscible, and irascible. Sense perception is not included in this order: in its formal aspect, it escapes the dominion of the will. It is undoubtedly the preliminary condition for all knowledge, but it is not its cause. And if we wish to articulate the order that exists between it and the intellect, we shall say that intellectual activity exercises an efficient-causal influence on sensory knowledge. However, this is a specific, isolated function of the active intellect, a function whose purpose is to legitimize the transition from the sensory image to the intellectual idea.¹⁰ The great human psychological hierarchy to which habit belongs begins only at the precise moment when man is master of his actions, and man is master of his actions only through the rational idea and the will that proceeds from it.

The order of dependence we have just described is general. It does not prevent the lower faculties from acting on the higher ones in certain respects. However, this action always takes place by virtue of a previously received impulse, and what ultimately has the final say is the order that originates in the intellect, continues through the will, and is consummated in the lower faculties. If I now actually will to take a boat, this is because I previously willed to cross the river, and ultimately, this is because I perceived this crossing as something good for me. If I wish to acquire this nuance in a particular virtue—calmness amid the ordinary vicissitudes of life, for example—this is because I previously perceived equanimity of the soul as something good for me. However, where does this judgment regarding a nuance of the virtue of fortitude come from, if not because the irascible part of my being had, through prior work, already been practically rectified in relation to the principal end of the virtue of fortitude. The subordination of the powers accommodates itself very well to the interweaving of the acts of these powers. In the final analysis, one must go back to an initial apprehension of the end, followed by an initial volition leading to an intellectual act regarding the means to be taken to achieve the end, then the will of that means, and finally, if it is an act of the lower powers, the realization in those powers moved by the will of the end through the means. This is what the table of intellectual and volitional acts illustrates, a classic pedagogical tool in Thomist schools.¹¹ It presents all the necessary intermediaries for the realization of a complete moral act. Each of the psychological acts must be considered as having a causal influence on the next. One must conceive of the sequence of these acts as unfolding from top to bottom and in parallel, though in obliquo, that is, in such a way that each act of practical intelligence appears as the determining principle of the corresponding act of will, and each act of will as the determining principle of the act of practical intelligence that follows it.¹²

The fundamental subordination of the powers foreshadows the subordination of habitus, which will be the proper perfections of these powers. The theory concerning the formation of habits through the actions of the higher powers upon the powers they command will justify this observation and make this subordination evident. Whether we are dealing with the powers, the acts of these powers, or the habits generated by these acts, the character of Thomistic psychology is one of causal subordination.

Realism and causal hierarchy: these are, in short, the two distinctive features of our psychology.

C. THE GENESIS OF HABITUS.

Two Capital Texts

Aristotle set forth in the first chapter of Book II of the Ethics the entire substance of the doctrine developed by Saint Thomas: “One acquires virtue by acting virtuously, just as in the arts, one learns how to create a work of art by actually making works of art, even if one has previously learned it in theory. The architect becomes an artist by building, the zither player by practicing. Likewise, by performing just, temperate, and courageous actions, one becomes just, temperate, and courageous—proof that these virtues do not come to us by nature. Consider legislators. Why have they fashioned the apparatus of laws, rewards, and punishments? To accustom people to virtuous actions. For this must be the intention of the lawmaker… Therefore, there is nothing we must watch over more closely than our actions. From their differences arise the differences in habits. It is therefore no small matter, but a great one, to ensure that our children adopt certain habits. Everything else depends on it” (paraphrase of Saint Thomas).

This is the teaching that Saint Thomas systematizes in ST I-II, q. 51, a. 3, which will be the subject of our analysis here.

Among psychological agents [sic], Saint Thomas first distinguishes and sets aside those that are incapable of transformation. “These,” he says, “are the agents that have within them only an active principle of operation. Example: fire is the principle of heating. For a habitus, in fact, cannot be caused in an agent by the agent’s own act (cf. ad 1); and hence it follows that natural things can neither acquire nor lose a habitus, as is stated in Book II of the Ethics.”

I assume the reader is sufficiently familiar with the language of Saint Thomas to adapt these ancient examples to a more contemporary idiom.¹³ If the example of fire that warms happens to offend anyone, I ask that they substitute a more modern example. The essential point is to bring into play the specific activity of an active cause. Saint Thomas contrasts this sort of agent—purely active—with those that are not so active as to be, as principles of operation, but in another respect, passive: moventia mota. He later calls this passivity a passive principle. Thus, I believe, we could consider the heatable capacity of a body set in motion by the heat of a hotter body as the passive principle of the heat-movement of the body being heated. And since action and passion are opposed, this passive principle must necessarily exist in a subject distinct from that from which the action emanates. The active agent will therefore gain nothing from its action. Throw a stone into the air ten thousand times, says Aristotle, and it will never get used to it. It is the secondary agent upon which it acts that will reap the full benefit of the action. For an agent to be transformed by its operation, it must therefore possess within itself not only an active principle but also a passive principle of operation. Such is the human agent, thanks to the immanence of its various operative principles and their subordination.

“Now,” continues Saint Thomas, “there is an agent that possesses within itself both the active and passive principles of its operation. Consider human acts: acts of appetite proceed from the appetitive faculty insofar as it is moved by the faculty of apprehension, which presents its object to it; in turn, the intellectual faculty, which arrives at conclusions through reasoning, has as its active principle a proposition that is self-evident.”

If you refer to the table we outlined a little earlier, you will find a kind of commentary on this passage. In this table, every act of appetite is moved by a preceding act of intellect. And just as, in the speculative order, the intellect that applies itself to conclusions derives from the intellect that perceives the first principles, so too do we see, in this same table devoted to the practical order, the intellect or will applying itself to the means (acts 7, 8, 9, for example) derives from the intellect and will insofar as these have the end as their object. The means to be employed is, in fact, deduced from consideration of the end to which it is proportionate; it stands in relation to it as a consequence or conclusion stands in relation to the principle that determines it.

Consequently, habits may arise in the intellect and the will, considered at the various stages of the voluntary act, provided that one accepts the first act of the intellect, which is purely active. Thus, St. Thomas concludes:

It is through acts of this sort that habits can be caused in agents: with the exception of the first principle of operation, which is purely active, all principles that move by virtue of the motion they receive are susceptible to receiving a habit: for everything that is undergoes action by another, everything that is moved by another, is disposed by the action of that agent, and thus, through the multiplication of its acts, a certain quality called habitus is generated in the passive and moved power. Examples: the habitus of moral virtues in the appetitive powers moved by reason; the habitus of the sciences caused in the intellect set in motion by propositions that are self-evident.

2. Commentary: Conditions for the Genesis of a Habitus

The time has come to distinguish and set aside the essential elements of this theory with a view to its subsequent application to what we have called “cosmic psychology.” We believe that three conditions are necessary for psychological evolution (as St. Thomas understands it).

A. First Condition: A Purely Active Agent.

At the causal origin of the psychological motion leading to the formation of habits, Saint Thomas places a purely active agent. Since all motion is a transition from potency to act, it must ultimately originate from a pure agent: actus prior potentia. And this agent must be such that it contains within itself and by itself a formal element that will be shared in the outcome of the movement it communicates. Otherwise, there would be no reason for the powers it brings into play to be subject to it.

The understanding of first principles satisfies these two conditions. Admittedly, during its formative stage, it itself depends on the sensory data that the process of induction aims to centralize, compare, and refine through an initial abstraction until these data settle into the appreciative (cogitative) sense under the guidance of reason grounded in experience. It is in experience—the fruit of the work of the sensory faculties, reflected by the imagination—that the intellect extracts (active intellect) and finds (possible intellect) the terms it conceives, which by such conceiving it transforms into pure ideas, which it then unites or separates in definitions and first principles. However, this dependence in the genetic order is not dependence in the order of causality, unless one is referring to material causality, which provides the necessary conditions for the development of an activity that is otherwise indigenous. In any case, once the mind possesses first principles, thanks to the spontaneous activity that unfolded upon the presentation of the terms of these principles through experimental induction, it is now constituted as “truly active” in act, indeed an act of a truly superior form. Therefore, if in the actions it will produce by bringing into play the powers subordinate to it, there is intellectuality—that is to say, truth—then, in the final analysis, this must be attributed to the understanding of first principles. The mind in possession of the first principle is virtually in possession of all the conclusions drawn in its light, each setting a limit upon the perfection of the principle’s truth by determining it to a particular truth.—The same is true of the understanding of the first principles of morality (synderesis, moral conscience) with regard to the volitional powers, whose object it modifies by making it conform to right reason. Synderesis thus governs the entire order of action, since it determines the conformity to reason of the ends, which are the great driving force of all action. Therefore, in the entire human psychological order, the understanding of first principles plays the directing and causative role played by the superior causes, celestial bodies, separate intelligences, and equivocal causes spoken of by Aristotle and Saint Thomas. The entire psychological order hangs upon it like a chain upon the closed ring that supports it. And as St. Thomas says: as God is related to the world, so is it related to the order that is its own (De Reg. princ., bk. 1). Keep all of these points in mind, for we will need them later on.

B. Second condition: The role of the passivity of subordinate agents

“Every patient or every thing that is moved by another is disposed by the action of that other.”

St. Thomas highlights here the property of the moved agent in relation to its mover. In short: passivity. For every action must correspond to a correlative capacity in the subject that receives that action. I say “correlative,” meaning that there is a natural relationship between the formal principle by which the action operates and this capacity. This capacity is in potency what that formal principle is in act. For how could it receive it if it were not in potential to receive it? How could the will receive the moral impulse that comes to it from moral conscience if it is not by its nature capable of receiving it?

And this action, says Saint Thomas, disposes the potency or “power” it moves. What does the word “dispose” mean? It means that the power, under the action of the agent, takes on the higher form of that agent. Thus the will, a purely appetitive power, under the action of the conscience which commands it to perform an act of justice, allows itself to be disposed by this motion and determines itself to perform the commanded act. The form of the superior active power has, for an instant, subjected the form of the inferior power; it has determined its native spontaneity to follow its superior impulse and, for this reason, it has produced within it a transitory form that raised it to the rank of the superior cause itself. This transitory form is the disposition.

Why call it disposition? Because it prepares the subordinate subject for the superior cause. For what does it prepare it? To follow the impulse of this cause and consequently to abandon its indeterminacy and even its native dispositions insofar as these would pose an obstacle to this impulse. For the same law governs opposites. Thus, for example, the ideal disposition of the muscular movements required for the performance of a piece of music is realized through practice in the musician’s hand, and at the same time dispels, at least for a moment, the contrary muscular configurations. In this example, we find the concrete realization of all the elements involved in the theory we are explaining: an active agent, the habitus of art which resides primarily in the intellect; a suitable, passive, and indeterminate instrument, the hand; a transient arrangement of the hand’s muscles that thus produces, under the action of art, the desired effect; and, finally, the possession of the instrument’s native indeterminacy and a momentary, at least, elimination of the instrument’s own, native, and above all contrary dispositions.

C. Altering Repetition.¹⁴

Everyone is familiar with the phenomenon: a rubber ball thrown onto the ground momentarily takes on a shape that conforms to the flat surface acting upon it. This deformation mirrors the arrangement we have just described. It bounces back and seems to retain nothing of that initial deformation. We start the game again, and again, and... what no single throw produces, repetition eventually accomplishes. One final throw, and the ball is permanently deformed. It retains the imprint of the flat surface that acted upon its spherical shape.

This phenomenon, which we could describe in less crude terms, offers a specific instance of the general law for which the formation of habits is another specific instance. By dint of being disposed in the direction of the operation of the agent acting upon it, the moving power eventually retains its mark. At first, the imprint is not definitive. It is a disposition that strengthens at the expense of opposed dispositions. Just as the drop of water eventually hollows out the stone, so the repetition of the same acts eventually erodes the [undetermined] spontaneity of living power. The drop of water does not remove a fragment of granite at the first strike; it wets, it softens, it breaks down through chemical or physical actions; in a word, it alters the granite. Similarly, an intervention of the conscience does not create virtue at the first strike in violent or intemperate temperaments: but it disposes; a second, a third intervention will root this disposition, extend its scope of action while diminishing to the same degree the innate tyranny of the passions, altering it as much as psychological elements can be altered—and they are altered, in their own way. Then, a final act completes what the previous ones had begun. The simple form that constitutes the habitus is drawn from the prepared power. It imprints itself as a definitive mark, which henceforth, like a graft, holds all the vital forces of the power in which it inheres under its control and imbues them with its own mode of being. Henceforth, the intervention of the superior cause will be limited to setting in motion this substitute for itself, transposed into a lower world. It is no longer an instrument that needs to be raised to the level of its operation time and again; it is a secondary cause that needs only to be set in motion, like everything that is not the essential activity—and we know that a secondary activity cannot be essential. The evolution is complete. Normal life begins.

It is through this mechanism—if we can use the term “mechanism” for a reality that is essentially psychological—that the hierarchy of Aristotelian virtues is formed. The habitus of the first principles, by acting upon the potential intellect to draw conclusions, gives rise to the habitus of science or philosophy (sapientia) and, when the object of the intellect is human action or an external work, to the habitus of prudence and art. The habitus of the first moral principles (synderesis, moral conscience), by directing the intellect to realize the means of attaining the moral end according to a rational rule, equally distant from excesses and defects (medium virtutis, according to Aristotle), derives from the intellectual power the virtue of prudence (acts 5, 6, 7, 8, 9 of the table cited above). This, by rectifying the will in view of the good of others, the concupiscible with regard to pleasures, and the irascible with regard to its own end, always following the same measure, produces in their respective powers the principal virtues of justice, temperance, and fortitude. And thus, with an eye that is metaphysical (the ultimate perspective to which psychology must be reduced), look now on the entire soul of the man who has trained himself in virtue: he is enriched with stable forms, with permanent tendencies toward a good ruled by reason. The same holds true, mutatis mutandis, for the philosopher or the scientist. These forms constitute a hierarchy that remains even after they are definitively fixed, a hierarchy that corresponds first to the hierarchy of natural powers, a hierarchy that manifests itself, in ordinary activity, through the order in which the principal motion emanating from the soul is distributed among the powers, and, in certain cases, through the intervention of the higher habits in the domain of the lower habits in order to expand their sphere of action. Thence comes virtuous activity, which now flows as though it were natural, though his man once upon a time was indecisive; and thence comes the scientist’s readiness to resolve the most arduous questions. Habit has become second nature to them. Indeed, this is what the genesis of a habitus invites us to see: the spectacle of the emergence of a new nature, necessarily grounded in the existence of a new form.¹⁵

How could we not call it an evolution?

D. Simple Genesis or Evolution

First of all, what do we mean by these terms: genesis, evolution?

The genesis of a thing is its production. Its simplest form occurs when an agent produces a being belonging to its own species. The Scholastics call this production “univocal generation.” Its primary object is the substances of things. The agent produces them by acting in a special way—“by eduction,” as Aristotle puts it—upon suitable matter. Accidental forms are “educed” in a similar manner. Here, the “matter” is the substantially formed being that lacks some accidental perfection. We use the term “simple genesis” for this generation of forms under the influence of beings with similar forms. This is, in fact, the spectacle generally offered by nature. It is the simplest case.

Evolution can be understood in two senses: one rational, the other irrational. In the latter case, evolution is the process by which one species changes into another under the action of certain circumstances. For those who use the term “species” metaphysically, this interpretation makes no sense. The rational sense holds that evolution is the process by which, all causes being in place, a concrete being belonging to a specific species finds itself at the starting point of a transformation that leads to another concrete being, belonging to a different species, generally superior. Therefore, in this sense of the term evolution, the specifying form—one, simple, indivisible—is not what evolves. Rather, the entire concrete, sensible being is what gradually loses its native qualities, taking on those that correspond to another being, until that moment when that other being is indeed established in existence. The most rigorous scientific theory of evolution (understood from a phenomenalist perspective) requires nothing more.

The genesis of habitus is not a simple genesis, since the habitus is a new form. Likewise, it is not an evolution in the irrational sense of the term, since it does not entail the metamorphosis of one form into another. Rather, it is an evolution in the rational sense of the term, and this sense is confirmed and illuminated by everything we have said. From the passivity of the being that serves as the starting point for genesis, the habitus is drawn forth, educitur, but before that takes place, a whole series of alterations preparing for it must unfold, evolvitur. Therefore, an evolution takes place under the influence of a cause that eminently contains the form to be realized.

In this sense—which involves neither the metamorphosis of one form into another, nor an ascent from the lesser to the greater, nor a spontaneous transition from potential to actuality—and in this sense alone can and must we speak of psychological evolutionism.

It should be noted that such an evolutionary approach does not rule out imperceptible transitions: on the contrary, except in the exceptional case when the agent is highly energetic and resistance is nil (ST I-II, q. 51, a. 3), it allows for a multitude of preliminary dispositions; and once the habitus has been formed, it accommodates itself, indeed quite well, to certain variations in the acts that emerge from these habitus, variations in intensity, promptness, adaptation to new aspects of their object, etc., for a natural power, while subject to constraints, remains nonetheless a living power. The scientist may err in a conclusion, just as an outgrowth may momentarily hinder the normal course of life. These are pressures that surge up from below, from matter, which in no way detract from the existence of a superior and dominant principle within one and the same matter.

Despite the immutability of metaphysical forms in themselves, despite the action of an efficient and directing agent, all the external characteristics that are usually attributed to evolution and make a system evolutionary are found in our theory of habitus.

Therefore, we can conclude this first part by affirming that Thomistic psychology admits the rational possibility and existence of a psychological evolutionism.

II. Metaphysics

Albert Gaudry recounted a visit he once received from Monsieur de Saporta: “From what I have seen,” said the illustrious botanist, “your research on fossilized animals has taught you that species are not immutable entities, but merely phases in the transformation of types which, under the guidance of the Divine Craftsman, continue their evolution through the ages. I have observed the same thing with fossilized plants. If you wish, we can work together. Let us enlighten one another, for what is true in the animal world must also be true for the plant world.”¹⁶

At the conclusion of this lengthy study, I believe that the Thomist who studies the nature of the psyche can say something similar. He addresses the metaphysicians of cosmological evolution and says to them: “Your research concerning the concrete beings of nature has taught you that they are not immutable entities. Well, we also observe the same phenomenon in a part of the psychological realm. Yes, certain species of this inner realm evolve: habits. If you wish, we can work together. Let us enlighten one another, for what is true in the psychological world must be true in the cosmological world.”

Must be true! What exactly is the value of this similarity between psychology and metaphysics? That is the preliminary question that must be resolved.

A. Hypothetical Analogy or Formal Analogy

Among modern philosophers, regarding the relationship between the data of psychology and those of metaphysics, we find two major schools of thought.

Some, such as the German pantheists of the school of Hartmann and Schopenhauer, hold that they are absolutely identical in nature. From a loftier, though equally pantheistic, perspective, Alfred Fouillée sees consciousness everywhere, at least in a rudimentary state, for he will say: the world is surely one; its unity cannot be attributed to a transcendent principle; therefore, between the most minute being and the most perfect being there is an identity in formal constitution. Consciousness is this immanent principle, which remains self-identical in all the realities it brings about through evolution, providing them with their fundamental unity.¹⁷

Others, by contrast, regard this similarity as a mere analogy. And it seems that, in their thinking, this analogy rests solely on a hypothesis that is more or less well-founded (e.g. Boutroux, in his recent work De l’idée de loi naturelle dans la science et la philosophie contemporaines). To the question: “What, in reality, does the action of things in nature consist of?” he replies: “This is something we can only conjecture by analogy, by considering what happens within us. Ultimately, consciousness is the only sense of being at our disposal.” And since it seems clear that the phenomena of consciousness known as habits bear a kind of resemblance to mechanical causality, it follows that we can find the image of inertia and mechanical force “in the persistence of our states of consciousness and in their reciprocal influence.” Thus, Boutroux takes care to tell us: “No doubt, this insight does not result from an induction based on scientific findings; it is merely a simple analogy.”

These are the two diametrically opposed viewpoints that currently divide opinion regarding the reality of the relationship between the physical and the mental. Fouillée goes so far as to identify them; Boutroux, after pointing out their resemblance, timidly retreats behind a Sully-Prudhomme style: “What do I know?” For “We ultimately fail,” he asserts, “when we seek to determine the substantial nature of things.”

I already discussed Fouillée’s system at length elsewhere. I will not revisit it here.¹⁸ The theory of conjectural analogy is far better suited to the mindset of many of our contemporaries than his own. Therefore, it deserves closer examination.

Its principle is that “consciousness is the only sense of being at our disposal.” External perception is hypothetical. Hence, we would need to resort to analogies drawn from the immediate perceptions of consciousness if we wish to assert anything concerning the nature of external realities.

This principle strikes me as highly questionable, and I will base the objection I raise against it on the authority of Kant himself: “Through external experience, I am as conscious of the reality of bodies as external phenomena in space as I am, through internal experience, of the existence of my soul in time, which I know only as an object of inner sense, through phenomena that constitute an internal state and whose being-in-itself, which serves as the basis for these phenomena, is unknown to me.”¹⁹

I am well aware that Kant intends thereby to destroy all noumenal knowledge of both the psychological world and the external world. And that is not what I approve of. Rather, I approve of how he places both kinds of knowledge on the same level. Whatever Descartes may have said, both are perceptions having a perceiving subject distinct from the perceived object. The wholly material identity of the thinking subject and the thought object that exists in psychological introspection cannot be identified with the formal identity of the two. Consciousness is no more a “sentiment of being” than external perception. In the knowledge of psychological being as well as in that of external being, subject and object remain opposed, and thus distinct, not only logically but physically, for the opposition of the thinking subject to the thought object is physical. Therefore, objective being is what we are dealing with in both cases. If this objectivity is an obstacle to the knowledge of the nature of external things, it is so to the same extent as it is for the nature of psychological things. And this is Kant’s postulate. If it is not an obstacle to the latter, it cannot be one to the former. In both cases, Descartes’s middle position—which denies truth to external perception in order to grant it to the testimony of consciousness—is destroyed. Therefore, there is only one way to escape total subjectivism, “that tomb of knowledge”: to resort to total objectivism. Is this not already a strong presumption in its favor?...

Besides, how are we supposed to prove that we are bound to fail when we seek to determine the nature of things? Undoubtedly, by arguing that things, when they become the object of knowledge, are distorted by the input of the senses, or at the very least, by the mind. And this reasoning applies just as much to the truth of psychological observation—considered as a “sense of being”—as it does to the truth of experience. However, is it really a proven fact that the mind and senses contribute their share of the object to knowledge? Has one really shown that there are forms of sensation or of understanding mingling with the impressions coming from outside? It is a mere supposition that antinomies would render the phenomenal world at most plausible if the antinomies were insoluble. As for the necessary character of first principles and universal notions, there is no reason to hold that this comes about as a kind of effect of subjectivity. Opposed to the Kantian hypothesis stands Aristotle’s position. For him, space and time are objective, just like quantity and motion, of which they are the consequent properties. The universal exists in individual things, not in the state of universality in exercise, but fundamentally—that is, with all the characteristic features of its concept, minus the faculty of being attributed to other individual beings, which remains proper to the [objective] concept [precisely as known]. For the mind, like the senses, contributes nothing that has the status of an object, no form, no category.²⁰ They are essentially in potency. There is no contradiction, incidentally, in the fact that a being, determined in its constitutive actuality, is actually indeterminate in its relation to other realities. Indeed, in such a being, potency and act are not opposed in the same respect. The presentation of the object to an empty potency—which is, moreover, essentially ordered to reproduce everything intelligible in that object—can thus take place purely, without falsehood. Kant’s assumption is unfounded. Aristotle’s is at least as plausible. And its plausibility is strengthened by the fact that, once Descartes’s position has been undermined, it remains the only one capable of saving the objectivity of our knowledge.

I am eager to point out that the special order of realities whose objective value Boutroux seeks to challenge is well worth discussing from this perspective. Thus, without subscribing to the general principle of conjectural knowledge, I agree with the specific conclusion he draws from it regarding the data of physical theories. Such is mechanical force, certainly conceived by contemporary mechanists on the model of the autonomous force we experience within ourselves. We readily concede that there is nothing more than a conjectural analogy in such claims. It is, if you will, even a form of anthropomorphism. However, in my opinion, it would be a mistake to identify these purely imaginative data with the substantial nature of things.

When the mind confronts one of the realities of nature, it does not produce an image through its intuition, but an abstract, sui generis unity, which it conceives as embodying, in the simplicity of its ideal being, everything that is specific to the real being under consideration. It then examines separately each of the secondary elements, determined by this fundamental element, and reduces them to intellectually distinct features. These intellectual realities, which constitute the structure of the psychological or physical world, are something primitive that resembles nothing else: they are not known by analogy, but in themselves through a process of abstraction in its first stage, and of intuition in the second. We do not perceive them sensually as we do force; nevertheless, once registered by the mind, they become terms with clear meaning, which can be associated according to the connections the mind discovers within them. For example, the notions of whole and part, once clearly isolated, clearly separated from the matter in which they are realized, and firmly established in the mind, will lead the mind to form the principle, the whole is greater than the part, a principle having an objective that is both general and particular (general because it is absolute in itself, particular because it certainly applies to the individual realities from which the terms in which I read it were extracted). If I am not mistaken, this amounts to more than the mere suggestion that realities make to the mind.

In conclusion: Between Fouillée’s system and Boutroux’s conceptions, between claims concerning the identity or heterogeneity of the psychological and physical worlds, an intermediate position is possible. One need only acknowledge the mind’s intuitive power with regard to essences. Through induction, the sense impression common to numerous experiences eventually settles in the highest realm of our sensibility. It is there that the mind finds it and, freeing it from the last bonds of contingency, renders it explicitly universal by conceiving it as such. The essence thus liberated is applicable to all concrete realities of the same intellectual type, whether they have been previously experienced or not. Suppose now that some of the experiences providing the material for this intellectual type belong to the psychological world and others to the external and cosmological world. Suppose that these experiences have been synthesized into a supreme experience, that the mind has formed a single concept from them, something common to both worlds—for example, the concept of habit. The essence designated by this word will be transferable to beings in both the psychological and physical worlds, taking into account, no doubt, the special conditions of each and adapting it to the material they provide, but preserving all its formal aspects. The resemblance between psychological being and physical being, insofar as they coincide in the essence extracted from each by the mind’s intuitive power, will be proportional, i.e., analogical, but also formal. For the same intellectual type, the same idea, the same form will preside over the inner constitution of both.

Therefore the similarity between the psychological and the physical will be less than identity, more than conjecture: it will be a formal and verified analogy. And what we say about psychological being and physical being in themselves must obviously be understood in terms of the laws that necessarily flow from their inner constitution.

Thus, with this master notion drawn from Saint Thomas concerning the intuitive power of the mind, we will interpret the key text we are about to quote.

B. A Key Text from St. Thomas (Summa contra Gentes, bk. 3, ch. 22).

This text forms the counterpart to the text we cited in our psychological section. The first described psychological development. This one concerns cosmological development. It constitutes Summa contra Gentes, bk. 3, ch. 22, which is titled: “The various ways things are ordered to their ends.”²¹ Before drawing our conclusions from it, let us briefly analyze it.

In the first part, beings are divided into three classes: some move, others are moved, and still others both move and are moved. The first are naturally the causes of the movement of the others: to be a cause is the very perfection of their state; as Saint Thomas puts it, it is that by which they resemble God. Beings that are merely moved are thereby destined to receive their perfection; their end is not to perfect other beings, since they move nothing, but to become perfect in themselves. This purpose is fulfilled when they possess their definitive form or reach the place toward which they tend. Moved movers possess both perfections: they receive and they give. To be more specific [and for now following the particular cosmology of St. Thomas, in order to thereby understand the deeper metaphysical point he is making], let us say that this latter class comprises celestial bodies, which occupy a position between the intelligences, which are purely movers, and the lower bodies, which are purely moved.

In the second part of this chapter, Saint Thomas identifies the specific characteristics of each group’s tendency toward its end. As we shall see, these characteristics are those of evolution as we defined it in our psychological section.

In general, superior agents combine the greatest of simplicity with universality; inferior agents, by contrast, can assimilate the perfection of higher beings only by participating in it, by fragmenting it. And this is why, instead of being on the same level as beings of the same species or even of a closely related genus, agents are arranged in hierarchical degrees. The higher agent acts upon the lower agent; the action is not reciprocal. Causality flows downward; it does not flow upward. The superior agent moves toward its own end, which happens to be the common good of the subordinate order it governs. And it is precisely through this that it attains this end. According to St. Thomas, the immediate end of the movement of the heavens is to occupy a specific place, but by that very fact it causes the alternation of day and night, the seasons, etc., and thus procures the common good of bodily substance, which is preserved, grows, and increases through generation. (We might say much the same today about the Earth’s movement around the Sun. [Translator note: Admittedly, this is a rather weak “analogy”…])

As we have said, inferior agents, under the influence of superior agents, tend to acquire their own perfection and the act that is this perfection. Now, says Saint Thomas (and here it no longer suffices that we analyze it; it must be presented directly):

There are degrees in these acts or forms. For prime matter is first of all in potency with regard to the form of elements (simple body). Once it exists in the form of the element, it is in potency with regard to the form of composites (compound body). And this is why the elements are the matter of the composite. Considered in the form of the mixed body, it is in potency to the vegetative soul, for this soul is the form of a mixed body. In turn, the vegetative soul is in potency to the sensitive soul, and the sensitive soul to the intellective soul, which manifests the progression of generation (in its embryological morphology). For the fetus first lives the life of a plant, then the life of an animal, and finally the life of man. After this last form, no further, nobler form can be found in this world of generation and corruption. Therefore, the supreme degree of the whole of [bodily] generation is the human soul, and this is what matter tends toward as toward its final form...

Therefore, if the motion of the heavens is ordered toward generation, and the whole of generation toward man as its ultimate end, it follows that the ultimate end of the motion of the heavens, within the order of beings that are born and move, is man… From this it follows (cf. chap. 23) that the prime mover of the heavens is an intellectual principle. For no agent tends, of itself, toward a form higher than its own, since every agent has as its end something similar to itself. The celestial body, through its motion, tends toward the supreme form, which is the human intellect: to which no form is comparable. Therefore, it is not the principal agent of the generative movement it brings about. It can only be the instrument of a superior intellectual substance. And since it is through its movement that it contributes to generation, it follows that it is moved by some intellectual substance.²²

It will be clear to everyone that this document sets forth what Saint Thomas [himself] considered to be the structure of the world and the elements of its genesis. However, at first glance, this genesis appears to be strongly tinged with a kind of evolutionary outlook! Let us determine to what extent and under what conditions.

C. Commentary: Conditions of Physical Evolution

The parallels between the document we have just analyzed and the one that provided us with the elements of a “psychological evolutionary theory” according to Saint Thomas cannot fail to strike anyone who compares the two texts. For Saint Thomas, the psychological structure of the man who has reached full human development through the virtues, and the structure of the world that has reached the pinnacle of its evolution, are exactly akin. On each side, we find three main components: a superior, intellectual agent, and subordinate, hierarchically ordered agents, some of which are purely passive, others both passive and active. An intellectual and moving current animates this organism. Under the influence of repeated actions, the powers in the psychological world and matter in the cosmic world gradually depart from their previous determinations to evolve toward a higher perfection. Then, in the final phase, alteration is followed by the formation of the new form, a habitus, or substantial form.

Everything is parallel in these two systems: the governing intelligence of the world and the understanding of the first principles; heavenly bodies and intermediate powers (reason and will) between the first intellect and the lower powers (irascible, concupiscible); the passivity of the lower, moved bodies and the passivity of the psychological powers vis-à-vis the intellect; and finally, there is the process of alterative repetition for psychological evolution and, no doubt, a similar process for cosmic evolution. Therefore, if the first evolution—psychological evolution—has been duly recognized as rational, we can predict in advance that cosmic evolution, with the same logical structure, will also be rational.

This is what we shall attempt to bring directly to light by studying more closely the text that has served as our basis, and particularly, the passage that we have quoted in full.

a. First condition: prime matter.

One word in this passage stands out from the rest and immediately troubles the modern thinker: the word “matter,” which must obviously be understood as the Aristotelian notion of prime matter: “neither what, nor what-sort, nor how-much, nor any of those things by which being is determined” (Metaphysics, 7.2). Evolution based on such an elusive entity? That seems like an empty dream! This seemed so a few years ago, back when material things, Taine’s facts, Wurtz’s atoms, and Berthelot’s substances were considered intelligible. Nowadays, all we hear about is the absurdity of matter. We now accept only a purified, spiritualized matter—a force attached to mathematical points for the Leibnizian objectivists, an unknowable noumenon, an intellectual construct for the lovers of the subjective. Consequently, Aristotle’s prime matter regains favor in direct proportion to the discredit that befalls concrete matter. Is it not, in fact, an intellectualized matter, the product of the mind attaching itself to matter perceived by the senses and analytically extracting the rudiment of intellectuality that constitutes it? As such, it belongs to the family of concepts forged by the Neo-Kantians, with the difference that our matter is not constructed but discovered by the mind. We define it as: real potency for substantial forms, a wholly passive power, unlike active psychological powers or faculties. We call it real, even though this reality proper to it does not possess an existence distinct from that of the physical compound of which it is essentially a part and from which it cannot in any way be separated.

This is already a rather sizeable victory: contemporary ideas allow us to speak without shame about prime matter. Nonetheless, we believe we are permitted to be more demanding. Does prime matter impose itself so clearly that it is the inescapable element of all evolution? That is the aim of the present research.

In a study on the human composite published here, we have already encountered this question. We resolved it by providing the traditional proof without altering it in any way. The reader may refer to that demonstration.²³ The proof I am about to give rests on the same foundation, namely the fact of changes in physical natures, but it focuses on these changes from a particular perspective—no longer in themselves but from the standpoint of their cause—which brings it closer to the proof we gave above regarding the passivity of human powers or faculties. Consider the proof:

Every change is explained by the influence of a cause on the changing entity. Consequently, the changing entity has the potency to receive the action of the agent capable of modifying it. This potency is set in motion toward the end intended for it by the agent. In fact, we see that the end toward which physical natures tend is, at times, the acquisition of an accidental perfection—quantity, quality, or place—and at other times a perfection about which we cannot yet speak definitively but which seems to deeply concern the very nature of the changing entity, as in chemical combinations or the phenomena of fertilization. According to Aristotle, the movements through which a physical being acquires accidental perfections are augmentation, alteration, and local motion. According to what we have said, they presuppose in the being that is their subject a specific passive potency vis-à-vis the action of the agent that determines them. It is precisely a potency of this kind that we have recognized in human faculties with regard to the formation of psychological habits. Now, it could happen that all the accidental perfections of a given being might disappear to make way for others. All that would be needed for this is a sufficient agent and a potency proportionate to that agent. At the limit, given the same conditions, it does not seem impossible that the principle of unity—which is at the same time the substrate of the inherence of all the characteristic qualities of a being—might give way to a principle of the same rank but of a different unification, appropriate to the different groupings of accidental perfections that have succeeded those which it sustained in existence. In this limit case, in order to be sufficient, the agent must be capable of moving the proportionate potency toward its first actuality, that is, toward a substantial and non-accidental actuality. The potency in question must therefore be devoid of all actuality, since it is the passive principle of the generation of the being’s first actuality. Obviously, a potency devoid of all actuality does not exist, as a physical reality, as a separable existence: it does not exist as a reality. Consequently, it can be affected by the action of the proportionate agent only within the being of which it is now a constituent part. However, it is because of its presence in this being that the agent will have a hold over it, for the form of this being, by contrast, opposes the destructive action of a foreign agent seeking to substitute another actuality for it. Matter, by contrast, which is essentially a potency that can be impressed upon by the agent, favors its action. And if the agent belongs to a higher order than that which has matured into the currently existing form, if it is more dignified in the hierarchy of forms and, correlatively, more powerful in the order of causes, then there can be no doubt that it will achieve its ends. And thus, we will have the evolution as described by Saint Thomas in the passage I quoted in full earlier and which we can now reread and understand: “In the acts of forms, a certain degree is found. For prime matter is, in potentiality, the first toward the form of the element, etc.”

The attentive reader will notice that so far we have not proven that prime matter is a reality. We have merely demonstrated the reality it would possess, if it existed, by considering it as a limit case of the physical potency to the movement toward the forms that constitute the inherent perfection of inferior beings. Is it now this reality, in fact? That is simply a matter for experimental observation. At first glance, no doubt, changes in nature concern only accidents: hence, we have the superficial systems of philosophical atomism and even of dynamism, which elevate the category of quantity or that of quality (its second species, potentia) to the ultimate foundation of things and admit only modifications of form or alterations of dynamic intensity. Upon closer examination, however, we can recognize that many of these changes entail the simultaneous disappearance of characteristic properties and the grouping of common properties specific to the being under examination, and their replacement by other specific properties and a different grouping of common properties. How can this phenomenon be explained? Undoubtedly, the disappearance of the consequent does not entail the destruction of the antecedent, but the appearance of a contrary consequent proves this destruction. The immobility of the corpse, for example, does not immediately entail the certainty of the soul’s disappearance, whereas the appearance of symptoms opposed to its presence—decomposition, for instance—does entail it.²⁴ Let us apply this principle of logic to the resolution of the present debate. Undoubtedly, we might say, the disappearance of characteristic properties and of a specific grouping of common properties does not entail the destruction of the cause of all this. However, the definitive, permanent substitution of other characteristic properties and of a new specific grouping of common properties can have no other cause than the presence of the fundamental unity that specifies the being thus modified. For a unity changes as a simple reality, that is, as a single, undivided whole. Therefore, we may conclude that in certain phenomena (and chemical combinations, as well as animal and plant genesis, seem indeed to belong to this type) there is a disappearance of the very form that constitutes the fundamental unity of all actuality of being, and the genesis of a new form and a new unity.

In accordance with the principles established, this essential modification can take place only through the intervention of an agent capable of determining the movement toward the new form, in a potency inherent to that form, which is consequently intrinsically devoid of any actuality, since it must receive its first actuality from that form—and this potency must be found in the being upon which the agent acts. It is a constituent part of it, just as it will shortly be a constituent part of the new being. This potency realizes the very notion of prime matter. Therefore, we can affirm that prime matter, a fundamental element of our evolutionary theory, is a necessary reality.

b. Second condition: A Moving Intelligence.

At the starting point of this evolution, whose fundamental élan is to attain the intelligence that is its supreme perfection, Saint Thomas rightly places a moving intelligence. In the physical world, it occupies the place held, in psychology, by the understanding of first principles, which similarly plays the role of making the whole of man rational, all the way to his animal passions.

This primary agent of evolution undoubtedly possesses a life of its own, an immanent life composed of intelligence and love as well, since it is active. For the moment, we will not attempt to penetrate the mystery of its inner life. We regard it as the primary and supreme condition of evolution, “which tends toward the human soul as toward its ultimate perfection.” In truth, the élan of the process of generation as a whole toward an intellectual form clearly indicates to us that an intelligence is necessary in order to govern evolution; however, this fact tells us neither why it intervened nor what this intelligence is.

To justify the reason for this action ad extra by the intellectual substance that governs evolution, it follows (on the established principles of Aristotle and Saint Thomas) that such an intellectual substance must have found its own good in this exercise of its activity, not some foreign good, as is the case, at first glance, for the existence of the human soul. And if evolution were to stop at the human soul, the intervention of the moving intellect, however evident it might appear, would remain misunderstood. But though the evolution of bodily nature does indeed stop at man (post hanc autem formam non invenitur in generabilibus et corruptibilibus posterior forma et dignior), with the human soul psychological evolution begins. What does this mean? It means that man, in turn, through his intelligence, retraces the entire chain of causality, which, having descended to prime matter, has risen upward to its end. He knows the nature that surrounds him; he penetrates it in its essential dependence, in its nature as participated being. He retraces the path of the gifts from above, and thus returns, now in an intelligent way, what he has received by way of causative influence. The intellectuality dispensed by the moving intelligence is not lost: it returns to it as to its final cause. Its thought forms a closed cycle, which, starting from Itself as efficient cause, returns through the endless chain of beings to Itself as final cause. And that is not all: at a certain point in this evolution, it found itself reflected in a creature whose mind (esprit) imitates its own, who conceived the world as it itself had conceived it in its Idea, and who, through the exercise of its rational virtues has intellectualized all that was irrational within it (animal life, vegetative life, and even his material limbs), thus accomplishing in this abbreviated world, through an entirely internal evolution, what It had Itself achieved in the physical world through an evolution of the same sort. Understood in this way, evolution is justified. It finds in the motive intelligence its efficient cause, final cause, and finally its exemplary formal cause.²⁵

What is this moving intelligence? The reader might be surprised that we have not yet mentioned the name of God. Therefore, joining the ranks of certain interpreters of Aristotle, should we say that the human soul is directed solely toward the world’s moving intellectual substance, which is responsible for leading it back to God, its ultimate end, through the acts of its own intelligence and will? Shall we say that God moves the world only in an objective way, as the supreme intelligible and supreme desirable being, and that it belongs to the separate intelligences, set in motion by this vision and desire, to move the world of bodies by efficient causality and illuminate lower minds (esprits) by an action similar what St. Thomas has to say about angelic illumination? I am well aware that Aristotle leaves himself open to this kind of interpretation. However, this is not the time to discuss this exegetical question.

From the standpoint of philosophical “dogmatics,” we must say with St. Thomas, interpreting Aristotle not by an isolated text but by his consistent principles, that God, if He is the final cause of the world, is also its efficient cause. Without this, the world’s ordering to God would be inexplicable. How can we expect a separate intellect to be precisely constituted to understand a being different from itself, unless it is its object that has given it this capacity? Actus prior potentia. Material form follows function; the function creates the organ. And how can it be created, if not through a causality that has its original principle in an efficient cause? Undoubtedly, these formalities of causality—efficient, formal, final—are not distinguished in God as they are in us. We are forced to distinguish different relations within this simple and eminent unity, just as within the unity of a circumference the geometer distinguishes the three vertices of the inscribed triangle, even though these points do not exist as distinct entities within the continuous line to which they belong. Thus, the eminence of divine causality ad extra encompasses the aspects of formal cause, final cause, and efficient cause without being restricted to any one of them. Therefore, Aristotle was able to focus more specifically on its finality in some of his works without this necessarily detracting from its quality as the first efficient cause.

Moreover, we must note that this efficient causality must have been exercised directly in three cases: in the production of separate intelligences (assuming they exist); in the production of prime matter, at least in its elementary form; and in the production of the human soul.²⁶ And this has already been proven with regard to separate substances. But could separate substances produce prime matter and the human soul? No. The human soul is a simple substance, and prime matter is the initial state and very first rudiment of being. Therefore, their production can only be a production “from scratch”, an act of creation. Now, to produce a being from scratch, to cause the entire being of a being, is to cause that being as a being. But, being as a being, which is an effect, can only be caused by the being as being that is not an effect, or unconditioned, as one says. Being as unconditioned being cannot admit of a limit, which would be a condition of its being. Therefore, it is not restricted to any one of the forms of being. The separate intelligences, inferior causes that are likely many in number, have forms that limit them. Therefore, they cannot create either the prime matter or the human soul. Q.E.D.²⁷

Thus, Saint Thomas, in the passage we are interpreting, while connecting evolution to the action of the moving intelligence of the first heaven, presupposes the existence of prime matter upon which this intelligence must act. Likewise, he is careful to say that the motion of the first heaven has as the aim of its élan the human soul, not that it produces it.

From all this, we can say that while the guiding intelligence of evolution is not necessarily and immediately God Himself, it acts as the generative and final cause of evolution under the influence of the divine cause: indeed, the very end of this evolution lies beyond its power; it tends toward a goal of which it has no idea or model of its own. God, however, possesses this idea, since it is He who brings the human soul into being by creating it. Therefore, the governing intelligence of this world, as the primary source for us of the tendency of all evolution toward the human soul, is necessarily the instrument of God. Thus, evolution ultimately proceeds from God, and in its return, through human thought, the moving intelligence is merely a transitional stage and not a necessary one, for the intelligence directly coming from God is directly oriented toward God.²⁸

c. Third condition: the heavenly bodies.

The old system. All things considered, evolution would be possible with a single equivocal agent, God, and agents that are inferior and passive in relation to Him. However, this sort of gap would rouse a kind of opposition in reason.²⁹ In the psychological order, between the understanding of first principles, which governs the whole of man, and the passions, whose only right is that they be directed, there is the understanding of conclusions, and the will, alternately commanded [by the practical intellect] and directing [in the order of efficient causality]. Why, then between the divine intellect and matter, should we not recognize, parallel to the psychological order following the separate intelligence—which is like the understanding of conclusions—bodily agents who, like the will, transmit to the lower powers, through their moving actions, the influence of the intellectual forms that govern them?

Undoubtedly, in the form it takes among the scholastic philosophers, the system of heavenly bodies is unacceptable to our modern science. And we would gladly apply to them the words of Pascal cited earlier: “To put it broadly… But to specify what they are and construct the machine, that is ridiculous, for it is useless, uncertain, and tedious.”

Equivocal causes do exist, and this is very important. It is in itself more natural—and more consistent with observation—to attribute the origin and persistence of certain intentions or general laws of nature to some of these equivocal causes, such as the sun or a distant influence from the movement of the primordial nebula, than to attribute all of this directly to God. Therefore, certain equivocal causes, even those that are physical, can fulfill intermediary functions between intelligent agents and material beings. The sound wave emanating from this man’s mouth, animated by his thought, will awaken in the ear and brain of the person to whom he is speaking an entire evolutionary process whose élan is directed toward the genesis of an intellectual thought. The listener’s mind goes to meet it: the idea springs forth, no doubt by the power of the mind, but thanks to the sound wave. Thus, in the Universe, God will think, and His Thought will strike a created, bodily being—some gigantic wave in the ether, if one wishes to replace the overly archaic celestial body with this term— and this wave will propagate. Driven onward by the divine thought that animates it, it will arouse new energies in lower beings, which will ascend from perfection to perfection under its influence.³⁰ At the summit of evolution, God Himself will place the crowning achievement—the intellectual form—just as, at the summit of the cerebral evolution brought about by speech, the spirit uttered the intellectual word. God alone creates the soul, no doubt, but in order for nature to be suitably prepared, the undulation of the ether was necessary.³¹ From the standpoint of the philosophical a priori as well as that of the a posteriori probabilities of science, we can therefore retain the soul of the old system and seek to give it a body. We are permitted, in this regard, to offer some indications, to point out some coincidences that may perhaps one day serve as a starting point for more certain constructions.

2. Overlap between the old system and the new. These overlaps, of course, do not concern the supposed central position of our planet. Needless to say, there is the elimination of the ninth heaven that governed all the others, the primum mobile of the ancients—or rather its transformation into the ultimum mobile, since the diurnal motion it used to explain is now explained by the rotation of the Earth itself.

i. First point of overlap. While it is true that the heavenly spheres are, at present, a mere figment of the imagination, nevertheless, in view of the nebular hypothesis—at least as far as our planetary system is concerned—they did exist. It is said that, under the influence of differences in velocity between the various layers of the moving nebula, spherical segments formed, as though nested one within the other. These hollow spheres, for a similar reason—through condensation, and who knows what else!— would have become rings similar to those of Saturn. These dislocated rings, still under the influence of the same causes, would have condensed into nuclei around a central nucleus, the Sun! And I have nothing against this explanation, and I apologize only for presenting it in such an incompetent manner.³²—Yet the ancients, though they did not see or know everything, understood what is certain in all this. They saw that the direct motion of the known part of our planetary system must be attributed to a single cause. Unum est causa unius. But since they did not know the history of the nebula, they conceived of this cause as present and the spheres as double rotating shells of transparent matter in which the planets were fixed. The planet was carried by the motion of its sphere, just as a point on a circumference is carried by the motion of that circumference.³³ They also distinguished the spheres according to the planets they knew and the differences in their movements. Saturn, Jupiter, and Mars were (along with their corresponding spheres) under the direct influence of the first heaven; Mercury and Venus (along with their spheres) served the movement of the Sun. All of this makes perfect sense. The error was to attribute to currently existing and active spheres the uniformity of a motion that originates from a sphere now absorbed into the planetary cores.

Therefore, the ancient philosophers were not mistaken in asserting the influence of the spheres—intermediaries of a higher order—on evolution. They were mistaken about the time period. The influence of the spheres was active during the genesis of the solar system. Let us not forget that the Earth’s rotation around the Sun is the continuation of the movement that once carried, within the same spherical orb, the hollow sphere and then the nebular ring that became the planet Earth. As for the planets, their apparent inertia with regard to our evolution resembles rudimentary organs in animals that are now useless, but which would have served in the initial formation of the globe where evolution, having begun with intelligence, was destined to reach its culmination in intelligence.

ii. Second point of overlap. The removal of the ninth heaven makes the eighth sphere the sphere of the stars, the primum mobile. Is this a notion that modern astronomy finds completely foolish? Does not the current translational motion that is ordinarily attributed to the solar system derive, as a whole, from the motion that animated the primitive cosmic nebula before the stellar centers were formed? I pose the question. If it is resolved in the affirmative, which seems to harmonize well with Laplace’s hypothesis, does not the primordial nebula, with its motion represented today by the stellar spheres, constitute, in terms of efficient causality, the primum mobile of the ancients? Let us not forget that there is always, in the way Aristotle and Saint Thomas conceived these keystones of the world’s genesis, a philosophical element that must endure, and a physical apparatus that may perish. That there be intermediate movers, moventia mota, and among them a first primum mobile—this, while not necessary, is grounded in reason. That the first mover was Laplace’s nebula, that its motion survives in the stellar spheres—this seems consistent with cosmogony. It is therefore appropriate to accept this, subject to further examination.

iii. Third point of overlap. It is through local motion that the primum mobile set the lower spheres in motion and reached the realm of qualitative, inorganic, and organic transformations. Modern science is not far from expressing the same idea. First of all, it is through a local motion derived from the motion of the primordial nebula that our Earth maintains its position in the circular ubi where the Sun can influence its evolution in a beneficial manner. The Sun, in turn, is said to owe its conflagration to the fall of matter that has not yet been concentrated.³⁴ This is the final stage in the evolution of the nebula as it pertains to our planetary system. Here we see local motion generating heat. Heat, in turn, becomes the source of the electrical forces so curiously distributed across our rotating solenoid. These are the three agents—local motion, heat, and electricity—that appear to be the instruments through which higher causes act upon earthly evolution. The first is linked to the nebula’s initial movement; the last affects our planet, where it causes countless phenomena of chemical combinations, actions, and reactions in plant and animal organisms. Undoubtedly, it is difficult to specify anything in this age when the most common elements—the air we breathe, the light we thought we knew—reveal new secrets to us every day: despite the vagueness of these points of overlap, I nevertheless believe that we can regard the physical agents—heat, electricity, etc.—aroused by the local motion of the primordial nebula and maintained by a pre-established harmony in a state where they are useful, as the successors of the heavenly bodies in their functions as equivocal causes, as providential intermediaries.

D. The Evolution of Habits: Its Characteristics.

Aristotle had limited psychological development to habits: he had formally excluded the faculties from it. “It is not by looking or listening,” he says in Book 2 of the Nicomachean Ethics,³⁵ “that one acquires sight or hearing. We possess these senses before we use them.” Therefore, someone might conclude: Aristotle is opposed to the evolution of natural realities. No, we would reply: he is only opposed to the evolution of forms inasmuch as they are forms. There is, in fact, a great difference between saying that forms transform and saying that a physical being transforms. I borrow this response from a commentary on another passage from the chapter of the Ethics that I just cited: “Natural things,” says Aristotle, “do not acquire habits; throw a stone into the air ten thousand times, and you’ll be none the wiser!” Why is this? asks Saint Thomas. And he answers: “Because, even if we place natural things in the circumstances most favorable to their transmutation, allowing them to be both passive and active (we know that it is to this property that faculties owe their ability to generate habits), the natural inclination they possess—which is essentially directed toward a specific object—will always remain. The action would have to be strong enough to remove the principle of their own activity. But if the principle of natural inclination is removed by this action (this principle is the form), then we have a new nature.” Let us note well that Saint Thomas in no way rejects this possibility. For him, it is a question of the agent. Therefore, let there be one of those agents we have called equivocal causes—heavenly bodies, separate intelligences, and ultimately God—and the transformation may take place. Undoubtedly, in the present state of the world, such transformations do not exist, at least among beings even slightly elevated in nature. “It is not by seeing that one acquires sight.” But at the time of the world’s genesis, when the great evolutionary forces were at work, who knows? This is a matter of fact that only direct observation could have settled, which the “posthumous” observation to which our scientists devote themselves can predict with varying degrees of probability.³⁶

Earthly evolution, thus understood as an evolution of physical beings rather than of forms, can now be described in terms of its principal characteristics:

1^st characteristic. — It strictly adheres to the two doctrines of the metaphysical simplicity of forms and the proportionality of causes to effects.

“That by which a thing obtains its specification must be fixed, stable, and as it were indivisible: everything that attains this indivisible belongs to its species. Everything that deviates from it to a greater or lesser degree belongs to another species, for, as the Philosopher says (in Metaphysics bk. 8), “Species are like numbers; a single unit suffices for distinguishing their species.”³⁷ All the requirements set forth in this masterful exposition by Saint Thomas are met by evolution as we have just explained it. Equivocal generation presents no greater difficulty than univocal generation. Higher beings of nature—plants and animals—daily accomplish a kind of elevation, before our very eyes, as they transform lower beings into their own substance. Therefore, is it not possible that extrinsic causes that possessed these forms in an eminent manner might have accomplished this sort of thing? Why couldn’t they have externally pushed matter toward that perfection which, once established and substantialized, becomes before our very eyes the center of attraction for an evolutionary ascent of matter? Undoubtedly, this transformation of beings—which causes simple “units” of form to disappear and reappear—requires a reduction, toties quoties, to prime matter. This necessity—imposed by reason, though unperceived by the senses, even as they provide the elements from which it is deduced—is so far from displeasing us that we make it the very foundation of our theory of evolution.

2^nd Characteristic.—The absence of miraculous intervention. Amid the course of this evolution (except for the gift of rational souls), God does not need to intervene specially or directly. There may be two aspects to general Providence: one that brings about evolution through the direct action of subordinate, equivocal causes, and the other that simply sets into motion beings already constituted in their being. The first acts through instrumental motions, the second through ordinary physical premotion. In relation to evolution specifically, Providence can be called “special” because the equivocal cause then acts according to its own form and not by setting in motion a second univocal cause. Thus, assuming that the action of the sun (as Saint Thomas admitted following Aristotle) would generate lower animals (worms and “ranas”), there would be no need to resort to a direct and special intervention by God to explain this appearance. In truth, the distinction of forms has its ultimate explanation in God. This is what Saint Augustine recognized when he attributed to God’s creative action, within the amorphous matter of the world, the production of the “seminal causes” of all things—a kind of system of “involutism” revived in our day by Wigandt. However, the same Saint Augustine held that secondary causes brought about the sprouting and evolution of these first seeds of things. One can, without accepting involutism—which is highly problematic—acknowledge that God is the ultimate cause of the distinction between things without being the direct, specific cause of their evolution. “Bodily forms,” says Saint Thomas, “are not placed in matter by an immaterial form. A composite agent is what that brings matter to its actuality. However, since the composite agent, which is a body, is moved by a created spiritual substance, it follows that bodily forms also derive from spiritual substances, which do not give the forms but move toward forms. Ultimately, the very ideas of the angelic intellect—which are like seminal causes of bodily forms—are traced back to God as their first cause.”³⁸

Thus, in psychological development, habits are formed only through the intervention of higher reason, or of higher habits already formed. For example, in the moral order, once higher reason has been educated and perfected by prudence, the habitus of first principles—the source of this education—no longer intervenes directly, except in exceptional cases. In the speculative order, the geometer does not trace every theorem back to the first principles of geometry, even though these principles are the origin of the conclusions he currently deduces.

3^rd Characteristic.—Its capacity for synthetic adaptation to the two general processes (considered by many to be irreducible) by which modern evolutionists explain evolution: the system of imperceptible transitions from species to species (Darwin), or the system of abrupt leaps (Hartmann).

All the causes of imperceptible variations cited by Darwin—natural selection, heredity, variability within a given level, the influence of external circumstances on a pre-existing tendency, the demands of instinct in relation to use and disuse, sexual selection by virtue of preference, the law of correlation of growth and modification in an organism—all of this, I say, explains nothing. For these are facts rather than causes. Or if they are causes, they are instrumental causes wielded by a higher and, ultimately, intelligent agent.³⁹

Insofar as accidental variation is directed toward the production of a new being, it is in reality the counterpart to the disposition that, in the psychological realm, prepares the generation of a habitus. It proceeds from a higher cause. If this cause belongs to a notably higher order—of intellectuality and energy—than the form of the being that is to evolve, and if it acts with full efficacy, then the dispositions it begets will be proportionate: we shall then have heterogeneous generation.⁴⁰ Such is the horticulturist who suddenly introduces into the vital circulation of a plant a graft that causes it to change immediately. At the extreme, that is, when God acts by exercising His infinite power, we will have creation in instanti, which is the final word on heterogeneous generation and the possibility of there being a “leap” in being.⁴¹ If, on the contrary, the cause in question is not significantly superior, in form and activity, to the form of the being to be destroyed, we will have a thwarted action, which will manifest itself as an imperceptible evolution. In this way the artist’s dexterity is formed in a naturally rebellious hand. At the extreme, we will have the generation of the like by its like, the univocal generation that no longer implies any evolution. Evolution therefore lies between these two extremes: creation on the one hand and univocal generation on the other. It is essentially characterized by equivocal generation, which synthesizes and reconciles the two major prevailing theories of imperceptible transitions and that which claims that leaps take place from one level to the next.⁴²

4^th characteristic.—Our doctrine is consistent with the fact of present-day variability and explains it. As Boutroux so aptly puts it, Aristotelian species, insofar as they are actualized (organic species, not metaphysical species), are not absolutely fixed:

Ideal types, in fact, are not and cannot be exactly realized by matter; they represent models around which nature gravitates, which it tends to reproduce, but which it never realizes except imperfectly. Thus the fixity of the species is a completely ideal immobility, allowing for—indeed, even calling for—a real and, in a sense, indefinite variability, while at the same time preventing any being from permanently crossing the boundaries of the species to which it belongs.— According to this doctrine, even cases of congenital abnormalities find their explanation in natural causes. These are extreme dissimilarities resulting from excess or deficiency. They stem from the dualism of end and conditions and from the capricious mobility of matter. Matter never fully realizes the form. Sometimes it deviates from it considerably.⁴³

Everything in this description is worth noting: the separation of both metaphysical and physical species by partitions that are, in a sense, impermeable; the variability of the physical species within the domain of its specific compartment; the two forms of this variability, one normal and of small scope and the other broader in scope, a congenitally abnormal case without, however, reaching the point of heterogeneity; matter, the intrinsic cause of this variability, which in a certain sense may be indefinite (under the influence of equivocal agents, the raw material being potentially capable of all forms); the extrinsic cause of these variations, namely the dualism of end and conditions, which amounts to saying that ends different from those currently realized by matter, or conditions different from those that presided over this realization, can act on the “capricious mobility of matter” and, though powerless to replace the form it possesses, succeed nonetheless in causing matter to oscillate, as it were, around it.⁴⁴

In the psychological world we find the counterpart of this oscillatory movement. The formed, fixed habitus retains a certain leeway: it is more or less rooted; it is more or less complete on the object’s side: science, for example, grows daily, when practiced, in vigor and scope. The essential indeterminacy of the faculty vis-à-vis the perfection that the habitus adds to it is here the counterpart of the indeterminacy of matter. It can also diminish, if not exercised, under the influence of natural causes that tend to restore the faculties to their native dispositions.

The inferiority and limited effectiveness of the causes currently acting upon established species are the occasional cause of their fixity.⁴⁵ Hence, we can classify organic species according to their characteristics and external form. “In plants and animals, the best criterion for distinguishing species is their external form, and this is because, on the one hand, quantity is the accident closest to substance, and on the other hand, form is the quality proper to quantity.”⁴⁶

Hence, we subsequently have heredity, which manifests itself in minute details and which denotes either the habitual intervention of a condition that causes it, or a conformity to the form intrinsic to the hereditary particularity.⁴⁷ Hence, finally, there is the continual ascent of lower species toward higher species through nutrition and assimilation. These phenomena are nothing other than the continuation of the action of equivocal causes. It is these, in fact, which, by acting upon matter, have determined it to rise to those forms that have become its permanent property. Now established, they continue for their own benefit the action begun by their nurturing mothers. Thus, in the psychological order, once virtues are formed under the action of reason, they themselves become centers of rational action and give rise all around them to dispositions, tendencies, and minor virtues that expand the influence they exert over the powers shaped by them.

Conclusion

To ideas-force theories of evolution—this final word of evolutionist philosophy—we oppose the idea of an habitus-theory of evolution. We believe we can now say: species are habitus of matter. Different from habitus in that they are substantial in character, they nonetheless resemble them in their formal concept, through the principles and laws of their genesis.

The habitus-theory of evolution conforms to the two great rational principles of Saint Thomas: the necessity of a guiding and active idea; the impossibility of passing by oneself from the state of potency to that of act. These principles lead to the existence of a first act, which is also a First Thought. Without doing violence to the data, the habitus-theory of evolution adapts a rational framework to the facts and hypotheses of scientific evolutionary theory.

The habitus-theory of evolution finds striking confirmation in the laws governing one of the most thoroughly verified phenomena in the psychological realm: habitus itself.

The habitus-theory of evolution thus embodies the most beautiful generalization that the human mind is capable of conceiving regarding the entire course of the world. In point of fact, we are here extending to the genesis of the world what Saint Thomas so masterfully stated regarding its governance: “Man’s little governance is what most closely resembles the divine government. Because of this resemblance, man is called a “small world” (minor mundus, a microcosm). Indeed, just as every bodily creature and all spiritual forces are contained within the divine government, so too our bodily members and the other forces of the soul are governed by reason. And thus, in a certain sense, reason is in man what God is in the world.” (De regimine principum, 1.12)

The habitus-theory of evolution meets all the requirements of the Catholic Credo, provided that the intervention of intermediate causes is ruled out for the production of the first types, and that one remembers that a habitus may be instilled instantaneously by an infinitely powerful agent.

Finally, the habitus-theory of evolution opens up the most attractive horizons regarding the supernatural order, and although this consideration has so far played no part in our argumentation, allow us, in conclusion, to point to this supreme harmony.

* * *

What, then, is the meaning of this ascending march by which Nature, under the influx of God, soars through countless degrees toward a perfection that seems to draw it to itself? As we have already said, all this takes place so that there might be a matter in which the human soul may exist: the ultimate degree of all generation is the human soul, and matter tends toward it as toward its ultimate form... It is evident that the end of the motion of the heavens is ordered toward man, as the ultimate end in the order of generable and mobile things.

But why, then, does God multiply human souls? Is it so that they may return to Him, tracing back the chain of beings that led to them, doing so through a kind of upsurge of knowledge and love? Undoubtedly. But how many of these souls actually make this return to God?

Thus, the believer sees clearly that there needs to be a specific goal and mover, a new evolution. The Word of God will come to take on directly this human nature whose flowering He had brought forth from the bosom of the Father, just as the soul had already come to take on the body prepared for it by evolution.⁴⁸

Christ will become the cause of an entirely new evolutionary movement. Under His influence, material things will become the sacraments, and just as the forms realized in prime matter had culminated in man, the sacraments, under the action of the first heaven of souls, will ascend from Baptism to the Eucharist,⁴⁹ in order to produce grace in man. In turn, grace will be the principle of an entire supernatural psychological evolution. The theological virtues and the infused moral virtues will arise under its action just as, under the action of the understanding of first principles in the moral order, the acquired virtues arose in the natural order. From the perspective of faith, this is the ultimate goal of earthly evolution. For, as our holy Doctor proudly says: “We posit the motion of the heavens for the completing of the number of the elect… Therefore, we concede that, when the number of the elect has come to its fullness, the motion of the heavens will come to its end.”⁵⁰

But then, under the direct action of the glorious and glorifying Christ, there begins the supreme psychological evolution that will never end. Grace will be transformed into the light of glory, and in this light man sees God as He is, “sicuti est.” ⁵¹ This action will pour forth over the body itself, which once emerged from the lowest matter: “He will transform the body of our lowliness, conforming it to the body of His resplendent glory.”⁵² And under the breath of the Spirit, man will undergo the supreme transformation: “But we all, beholding the glory of the Lord with unveiled face, are transformed into the same image from glory to glory, as by the Lord who is Spirit.”⁵³

Here, human evolution comes to an end. But the believer’s eye glimpses further. In the very heart of the Trinity, it sees a mysterious activity, of which this supernatural evolution is a distant imitation, psychological evolution a faint reflection, and material evolution an indistinct vestige.

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1. See Ambroise Gardeil, “L’évolutionnisme et les principes de S. Thomas,” Revue thomiste 1 (1893): 27–45, 316–327, 725–737; 2 (1894): 29–42; 3 (1895): 61–84, 607–633; 4 (1896): 64–86, 215–247.↩︎

2. Marguerite Perier, Letters, pamphlets, etc., cited by Havet. (Pensées).↩︎

3. Boutroux, De l'idée de loi naturelle, chs. 10 and 14.↩︎

4. This evolutionary theory, as noted in connection with an article by Remcle (Rev. de Mét. et Mor., 1893, vi, and 1894, ii), leaves nothing standing and destroys itself. See the articles by Fouillée (R. phil., January 1894) and by Vouges (Annales de Phil. chrét., January 1895). Cf. the article by Fr. Sertillanges in Rev. Thom. (November 1893).↩︎

5. Trans. note: Fr. Gardeil seems to be referring to a thought experiment in Condillac.↩︎

6. Boutroux, De l'idée de loi naturelle, p. 44.↩︎

7. See the textbooks by Messrs. Rabier, Fonsegrive, etc.↩︎

8. See Lepidi, Critica della ragione pura, etc. It is in vain to claim that the existence of the object affirmed by the relation contained in this idea, with respect to its object, is merely a logical existence, and consequently a form of the mind analogous to time, a form of sensibility according to Kant (see Weber, Revue de Métaphysique et de Morale, January 1896, p. 51). There is a confusion between logically affirmed existence and logical existence. The relation to an object—an essential element of the idea—implies different causes of existence for the knowing subject ut sic and the object ut sic. If the existence of the object as such and the existence of the knowing subject as such were one and the same real existence, the essential opposition between the two would be inexplicable. For existence is an act of the essence, and here these two essences are distinct. Indeed, there is no more such thing as absolute existence than there is absolute time, unless by absolute existence one means the cause of partial objective existences.↩︎

9. Saint Thomas’s “Treatise on the Passions” is one of the most original parts of his moral philosophy. Bossuet drew heavily from it. Gardair recently highlighted its main features in his work Les Passions et la volonté, with his characteristic discernment.↩︎

10. Trans. note: For some further precisions on this point, see https://www.athomist.com/articles/toward-a-fuller-account-of-the-agent-intellect-2025.↩︎

11. Goudin, Ethica, ch. 2, art. 3.↩︎

12. Sequence of Acts of Intellect and Will that Constitute a Complete Moral Act (ST I-II, q. 8–19)

    

    NB: Read this table, as it were, diagonally, which is really just to follow the numbers.

    Trans. note: Technically, too, one can consider a kind of mutual causality of intellect and will for each side of this table, though in different genera of causality. This is clearest for the ultimate practical judgment, but it is arguably present at every stage of practical reasoning. For some discussion of this, see https://www.athomist.com/articles/reorienting-discussions-about-connaturality.↩︎

13. One can never be too cautious when dealing with certain minds. Recently, a distinguished writer, having read the example that Saint Thomas always uses to explain the actual subordination of causes—the movement of the stick, the arm, and the volitional idea—saw fit to object to the actuality of this transmission, citing the temporal succession as it emerges from modern physiological data.↩︎

14. I borrow this term from the expressive vocabulary of Weber (Rev. de Métaph. et de Mor., no. 5, 1893). It is not entirely accurate, for there are no alterations in the habitus, but only something analogous to alteration. See the earlier discussion in Revue Thom. 2.1, p. 40.↩︎

15. I quote here, to emphasize what we have just read and to show the depth with which Saint Thomas understood Aristotle, a passage from the admirable Chapter 9 of the Quaestio unica de Virtutibus: “Those things that are open to either alternative possess no form from which they are definitively inclined toward one particular thing; rather, they are determined toward some one thing by their own mover. And by the very fact that they are determined toward it, they are in some way disposed toward that same thing. And when they are inclined toward it many times, they are determined toward the same thing by their own mover, and a determinate inclination toward it is established in them, such that this superimposed disposition is like a certain form tending toward one thing after the manner of nature. And for this reason, it is said that habit is a second nature.” The entire article is worth reading. It contains the most detailed and synthetic description to be found in Saint Thomas on the acquisition of virtues.↩︎

16. Revue des Deux Mondes, January 15, 1896.↩︎

17. See Rev. Thom. III, p. 629.↩︎

18. As early as 1870, Boutroux refuted Fouillée’s theories in a way that seems to leave little room for rebuttal. See De la contingence des lois de la nature, ch. 7; De l'Homme, 2nd ed., p. 108.↩︎

19. Kant, Prolégomènes à toute métaphysique future, §49.↩︎

20. Trans. note: Certain nuances are necessary, however, to explain the estimative sense, though a complete account of these matters does not annul the basic points being made by Fr. Gardeil, even if such an account would be↩︎

21. Trans note: Gardeil calls it the “Summa philosophica,” a title that is questionable. The SCG is better understood as a theological text in apologetic mode.↩︎

22. The reader might wonder how we dare to invoke a document based on such outdated astronomical concepts in solving the quintessential modern problem. We reply: (1) The existence of intermediate causes, moventia mota, is not necessarily tied to the existence of Ptolemy's astronomical theories. It is an intellectual given that responds to our need to attribute to certain agents endowed with a general activity the production of the common conditions for the formation and existence of specific beings who are thereby causally subordinate to them. (2) The identification of these rationally necessary causes with certain bodies is, moreover, in principle far more philosophical than the explanation by the laws of nature to which one usually subscribes. These laws must have a cause: it may be an ordering intelligence, but it is far more probable that the proximate cause of certain laws resides in certain parts of the universe that constitute the unity of the others; for example, the Earth’s various positions around the Sun and terrestrial life. (3) Nothing prevents us from substituting new theories for these old ones, provided we do so with caution. And since “Now chance wanders amid the shadows / the awakened worlds of their illusions,” I will in no way contradict those who would like to substitute the ether and its magical properties for the dethroned heavenly bodies. I will only ask them never to identify, to the point of making them inseparable, the rationally necessary data and scientific theories. In this regard, Saint Thomas can serve as our model, he who takes care to say regarding the theory of his time on the rotation of the heavens: "etiam forte alia positione facta salvari possunt" (ST I, q. 32, a. 1, ad 2), and "si tamen hoc verum sit" (In De Caelo et mundo, bk. 1, lect. 3, p. 8, Parma ed.). Cf. Opusc. 9, Resp. ad mag. J. de Vercell., art. 1–5. Cf. Revue Thomiste I, p. 205 and note..↩︎

23. See Rev. Thom. II, p. 372 ff.↩︎

24. It was by overlooking this rule that Father Roure reproached me for regarding oscillatory motion as the starting point and the final word of Spencer's doctrine. "He in fact regards it merely as a corollary—albeit a significant one—of the persistence of force." And I had said so (Revue Thomiste, March 1894, p. 30)! However, having regarded the oscillatory rhythm or reversibility as a property of the persistence of force, I concluded from the non-reversibility of phenomena—as affirmed by experiment—that force does not persist. This is a necessary line of reasoning of its kind and the only one applicable in this case. Since we do not experience force, we can know what it is or is not only through its effects. (Études religieuses, March 1895, note.)↩︎

25. In II Sent., dist. 1, q. 2, a. 3c.↩︎

26. In II Sent., d.1, q. 1, a. 4c.↩︎

27. Cf. ST I, q. 65, a. 3 (with Cajetan’s comments). Also, De Pot. q. 3, a. 4c. 5a ratio.↩︎

28. Translator’s note: I must admit that, at first blush, the discussion of intermediating intelligences causes some intellectual exhaustion for me, as though a bit too slavishly attached to the very text of Thomas. Yet, discarding the problematic cosmology, there are nonetheless interesting points one might reflect upon regarding the role of the angels—and demons?—in evolution, always and ultimately under the moving causality of God. For interesting indications concerning this, see Jacques Maritain, “Concerning Animal Instinct,” in Untrammeled Approaches, trans. Bernard Doering (Notre Dame: University of Notre Dame Press, 1997), 132–150. One can also consult his essay on evolution which immediately precedes this text.↩︎

29. In II Sent, d. 1, q. 1, a. 4c. (“Sed haec positio stulta est.”↩︎

30. In II Sent., d. 1, q. 1, a. 4, ad 5.↩︎

31. For the record, I note the factual question that arises here regarding the bodies of the first human couple. This question is reserved for the Christian. Genesis attributes their formation to a direct and special act of God. The thesis set forth here applies to ordinary generation.↩︎

32. Faye, De l'origine du monde, ch. 10, p. 165 ff.↩︎

33. ST I, q. 70, a. 1, ad 3 (Aristotle’s opinion).↩︎

34. Faye, ibid., p. 222, — Cf. Secchi, Le Soleil.↩︎

35. Aristotle, EN, bk 2, ch. 1. — Cf. Metaph, bk. 9, ([Thomas’s commentary,] Lect. 4).↩︎

36. Gaudry, “Essai de paléontologie philosophique,” Revue des Deux Mondes, February 15, 1896.↩︎

37. ST I-II, q. 52, a. 1.↩︎

38. ST I, q. 65, a. 4.↩︎

39. “For certain species, successive modifications would have gradually brought them closer to one another: the undeniable evidence of these transitions is laid before our eyes in the rich collections of the Museum. The causes put forward by Darwin and his followers—natural selection and the struggle for existence—seem childish to me for such a prodigious result: the transformation of species. Hypothesis for hypothesis, I would prefer Lamarck’s, that the giraffe’s neck grew longer as a result of the efforts it made to reach the foliage of the trees.” (M. de Nadaillac.)↩︎

40. Cf. ST I-II, q. 51 a. 3.↩︎

41. In II Sent., d. 1, q. 1, a. 3, ad 3 and ad 5; De Pot., q. 3, a. 4, ad 16.↩︎

42. ST I, q. 45, a. 8, ad 3 (and Cajetan’s commentary); q. 65, a. 4; q. 115, a. 3, ad 2 (and Cajetan’s commentary).↩︎

43. Boutroux, De l'idée de loi naturelle, p. 85.↩︎

44. Plant species, says Wilmorin-Andrieux, are “like a kind of system having a precise center, though it is not always represented by a typical form (organic species), and around this center a field of almost indefinite variations, yet contained within positive limits.”↩︎

45. Cf. De pot., q. 3, a. 4, ad 16.↩︎

46. In VIII Phys., lec. 5 (§ Secundam rationem).↩︎

47. “Being, one might say, tends to become fixed in the form it has once given itself...: it takes pleasure in it and tends to persevere in it. This is what in man is called habit.” Boutroux, De la contingence des lois de la nature, 2nd ed., p. 170↩︎

48. Recalling, of course, that the mode of union in the hypostatic union differs from that of the soul and body.↩︎

49. ST III, q. 73, a. 3.↩︎

50. De pot., q. 5, a. 5.↩︎

51. 1 Jn 3:2↩︎

52. Phil. 3:21.↩︎

53. 2 Cor. 3:21.↩︎