Why Aquinas’s Metaphysics of Gender Is Fundamentally Correct: A Response to John Finley

Abstract

In an important article, John Finley suggests a correction to Aquinas’s understanding of gender distinction. Disagreeing with Aquinas, Finley proposes that gender distinction (male and female) stems from the soul rather than from the body. In this essay, I will show that this is not a tenable position because it does not fit with either what we know about the physical development of sex differences or the unity of man and woman as a single human species. I will defend Aquinas’s fundamental insights into the root of gender distinction without defending his biological understanding of the process itself. I will argue that there is a single generic generative power in the soul that is determined by the matter to which the soul is united, to be expressed as either male or female. This paradigm, I believe, copes better than the one offered by Finley with phenomena such as intersexed persons and sex reassignment surgery. While I do not accept the idea of a feminine or masculine soul, the paradigm offered here does lead to the notion of the soul being feminized or masculinized on account of the matter that it informs.

In his essay, “The Metaphysics of Gender,” John Finley (2015) has done us a service in thinking through the very timely and important issue of sex/gender,¹ from a Thomistic perspective. His article is carefully argued and has some important insights. That said, in this essay, I am going to disagree with his foundational position. I am not going to disagree with his interpretation of Aquinas vis-à-vis sex because it is, I believe, accurate. Rather, I am going to contest Finley’s correction of Aquinas on one central point. Aquinas says that sex stems more from the material principle in man than from the soul. Finley disagrees with Aquinas on this point and says that sex stems more from the substantial form, that is, from the soul. I will seek to explain why it is Aquinas, and not Finley, who is correct on this point.

Aquinas’s Position

As noted, I am not in dispute with Finley in regard to his interpretation of Aquinas’s position, but I do need to place this position (in summary form) before the reader in order to take up the question of whether sex stems more from the material or from the formal principle in man.

Finley helpfully expounds two texts from Aquinas in which the Angelic Doctor reveals his understanding of sex (Aquinas, Disputed Questions on the Soul a.12 ad 7 and On Being and Essence, chap. 7). It is worth noting that in neither of these texts is sex the central issue, so Aquinas’s exposition is frustratingly brief. Nonetheless, it is clear enough that Aquinas understands sex to be an inseparable accident of the individual (Aquinas, Disputed Questions on the Soul a.12 ad 7) and that this accident stems more from matter than from the substantial form (the soul; Aquinas, On Being and Essence, chap. 7).

An inseparable accident of the individual is an attribute that is present as long as that particular individual exists. Nonetheless, this reality does not constitute the core identity of the individual. It is, in this sense, like an inseparable accident of a species. Such an accident is not in the definition of the species, yet it is always present when an individual of that nature is present. For example, the act of burning is an inseparable or proper accident of fire.

Aquinas only gives sex as an example of an inseparable accident of the individual. However, one might imagine that temperament (choleric, phlegmatic, etc.) is also such a reality because, while temperament does not define the individual at the level of personhood, it is a characteristic that is always part of him.

To say that sex stems more from matter than from form means that matter is the determining factor in whether this human is male or female.² Aquinas understands the male/female distinction in terms of the specific contribution of each to generation. As Aquinas understands it, the male produces and delivers sperm, whereas the female provides another type of matter, namely, menstrual blood (Aquinas, Summa Contra Gentiles II, 89).³ Obviously, he is not wholly accurate in this but all that matters for the present purpose is that male and female are understood in terms of their unique contribution to human generation.

Since male and female are understood in terms of their unique contribution to human generation, this means that sex stems from matter only if matter (and not the substantial form or an accidental form of the soul) is the factor that ultimately determines which role the individual human ends up playing in human generation. Form obviously always plays a role, since nothing material can be actual without a form of some kind. Yet, the issue here is whether it is the soul or whether it is the matter (into which the soul is received) that ultimately determines which role the individual plays in human generation.

As a point of clarification, Finley is clear that sex is an attribute most strictly said of the whole substance (the body–soul composite) rather than of the soul alone. He says: “like sensation, gender is a characteristic of the composite substance, stemming from the soul” (Finley 2015, 598). Indeed, Aquinas is clear enough about this since the subject of a power is always that which is capable of operating, and it is the composite—the body and soul—that is capable of generating (Aquinas, Summa Theologiae I 77.5). Yet, to say that the composite is the subject of sex does not answer the question as to whether being male or female stems more from matter or from the soul.⁴

Aquinas’s metaphysics gives us at least three reasons to hold the position that matter is the determining factor in sex. One reason relates to his antiquated biology. Aquinas thought that a female child was the result of something interfering with the developmental process orchestrated by the male seed. The male seed, as the active component in generation (as he saw things), would produce a like effect (i.e., a male fetus) unless impeded in its work by some defect in the seed itself or by some external material interference (Aquinas, Summa Theologiae 92.1 ad 1). Hence, whether a male or female child emerged from the process of generation was the result of material factors. Conclusion: sex stems from matter.

The second reason to affirm that sex stems from matter is that the contrary position—that sex stems from the substantial form or from an accidental form of the soul—seems to compromise the unity of the human species (Aquinas, Metaphysics X, lecture 11). Male and female humans would be different species. The substantial form determines the species and so if the soul is feminine as such or male as such, we are dealing with two distinct species.

Even if sex were taken to be founded on the generative power understood as an accidental form of the soul, the problem of distinct species appears to remain. This is because the “package” of powers that flow from a substantial form is determinative (or at least indicative) of the species. For example, the addition of the rational powers (intellect and will) to the sensitive powers (imagination, common sense, concupiscible appetite, etc.) is what distinguishes humans from other animals. Hence, a soul with a specifically female generative power—even when this power is understood to be an accidental form—would imply a soul with a different set of powers as compared to a soul with a male generative power. Given the different set of powers, we would have distinct species.

The third reason (which is closely tied to the second) is that what pertains to the individual (and not to the species as such) falls on the side of matter (Aquinas, Summa Theologiae I 3.3). Now, clearly, sex is proper to the individual and not to human nature as such. Hence, sex stems more from matter than from the soul.

Finley’s Critique of Aquinas and an Outline of His Own Position

Finley sees various problems with Aquinas’s position. Finley rejects Aquinas’s understanding of the process of human generation. He points out that the determination of whether a child is male or female is not the result of whether or not the sperm was thwarted in the full exercise of its generative capacity.

Furthermore, Finley asserts that it is the soul alone that can organize matter in the way that it is organized in the case of sex, that is, into complex organs that have very specific purposes. Matter cannot, in Finley’s view, be self-organizing in the way that would be necessary to account for the generative organs. He quotes Aquinas himself: “the soul constitutes diverse parts in the body, even as it fits them for diverse operations [emphasis added]” (Aquinas, Disputed Question on the Soul a.10 ad 17).⁵

In order to hold his position, Finley understands that he needs to address the issue of whether it leads to two separate species. He appears to accept the logic that a distinctive soul-based power (like a sixth sense) would constitute a new species, different from human nature. Were there to be a creature with all the powers of the human soul (intellect, will, irascible and concupiscible appetite, sight, hearing, etc.) plus an additional power—such as the ability to sense gravity—then we would have something other than human nature before us. So, the question becomes: if the particular set of soul powers determines the species, how can one hold that the generative power (rooted in the soul) is either male or female and not end up with two distinct species.

Here, Finley makes a couple of points. First, that the generative power does not specify the soul in the way that the other powers do because “gender posits no further power in virtue of which the animal’s essence is determined; rather, it concerns precisely the maintenance of the essence” (Finley 2015, 601). The point seems to be that the generative power merely provides for the replication of the creature with a particular set of powers, and these (other) particular set of powers (excluding the reproductive power) are what specifies the creature as the kind of thing that it is.

Second, Finley focuses our attention on the apparently unique character of the generative power, namely, that it is a “co” power. This is to say that neither the male nor the female generative power stands alone. Rather, the one is only a capacity at all when considered in relation to the other. Alone each is impotent. Finley (2015) says, “the male and female powers are distinct not simply in the way that the five senses are many sense powers, but as mutually dependent contributors to one action: generation” (p. 602). According to this logic, the generative powers are insufficiently complete or autonomous to constitute powers that would characterize the form sufficiently to constitute a unique and different species.

Another way of stating this last point would be to say that all powers are differentiated by their object, and Finley is claiming that both generative powers (male and female) as co-powers have the same ultimate object. Hence, we are not dealing with distinct powers in the way that sight and hearing are distinct on account of their distinct objects, namely, color and sound. Finley acknowledges that the male generative power and the female generative power have distinct proximate objects (or objectives), namely, the production and delivery of sperm and ova, respectively; however, he sees the unity of their ultimate objective—the generation of human life—as more significant.

An Examination of Finley’s Position

Before launching into an examination of Finley’s position, I need to clarify more precisely what I understand by the categories of “female” and “male.” Obviously, this is necessary if I am going to claim that sex stems principally from the body. I do not think that my position on this is significantly different from Finley, but it is as well to make things as precise as possible.

I understand a female human to be “a human individual who has the active potency to develop the organ needed to produce ova,” and I take a male human to be “a human individual who has the active potency to develop the organ needed to produce and deliver sperm.”⁶

Here, I have been careful to use the phrase “has the active potency to develop” rather than merely “has the organ needed for the production of ova or sperm” because a woman who has had her ovaries removed (perhaps as part of a treatment for cancer) is still a female. Furthermore, a fetus who is moving toward the specialization of its gonads as testes, but who miscarries before maturation of these organs, is still a male.

The phrase “active potency” seeks to get at the fact that within the zygote there is an entelechy that moves the individual from within toward the specialization of the gonads as ovaries or testes.⁷ Certainly, this trajectory can be hampered or curtailed, but, in that case, there still is an inner trajectory that is hampered or is curtailed. That clarified, let us move on to consider Finley’s critique of Aquinas.

Self-Configuring Matter?

Finley is correct to say that matter cannot be self-configuring, especially when the material entity under consideration is highly complex and tailored to a very definite purpose (as the generative powers are). However, there is a way to understand how sex stems from matter that respects this truth.

The matter into which the human soul is infused is matter already under some form. This prior configuration is not “wiped clean” by the infusion of the human soul. Rather, the new substantial form actualizes the particular potential that is in the matter it receives, potential that is there on account of its prior configuration. One might say that the matter has information in it already, and the new substantial form—or more exactly an accidental form of the soul, namely, the generative power—reads this information and builds the generative organ that is encoded in the matter. The generative power builds that organ which is already present in the matter in potency. If the information is for a male generative organ, then the generative power (neither male nor female in itself) builds the male organ, and, likewise, a female organ, if that is what the matter encodes.

This articulation does not imply that matter is self-organizing. Rather, the formation and actualization of the matter (namely, the emergence of the generative organ) is an effect of the soul (via the accident of the generative power), but the matter fully determines whether the resulting organ is male or female. Hence, sex is determined by the matter as informed by the soul.

Eternal Frustration?

Finley holds that if the generative power of the soul is unsexed in itself then, since one sex will never be expressed, this would result in an inbuilt frustration in human nature, something that cannot be countenanced. He says, “upon the soul’s union with the body, an entire set of the soul’s powers would be in principle denied the possibility of fulfilment. Each human would naturally possess built-in frustrations on the metaphysical level, which opposes Thomas’s thought and the majority of human experience” (Finley 2015, 603).

I do not think that it is correct to speak of a frustration here. Rather, it is merely that when a potency is realized in one manner, this can exclude its realization of another manner and will surely do so when these actualities are mutually exclusive. The generative power is no more frustrated in being determined (by matter) to be male (rather than female) than my soul is frustrated when (at conception) it became the form of the matter that constitutes my body and not the matter that constitutes yours. Frustration requires that a potency is in no way realizable.

Certainly, as Finley notes, if one were born without eyes or ears, then the potency to see or hear would in no sense be realized: it truly would be frustrated. When the generative power is actualized as male or female on account of matter, it is truly actualized in some way and so it is not frustrated. Perhaps the closest we can get to the notion of the procreative power as a frustrated potency would be in the case of an intersex person in whom neither the female or male organs have correctly developed.⁸

Sex and Genetics

Finley is correct to reject Aquinas’s antiquated ideas about human procreation. Aquinas was unaware of the existence of the female ovum and gave all the active agency to the male seed. His understanding was that the semen was “gunning” for a male child, but material processes that thwarted the activity of the semen accounted for a female child. Matter determined the outcome. We now know that this is not a plausible explanation of how sex distinction comes about.

However, this only shows that one argument offered by Aquinas in favor of sex stemming from matter is unsound. Demonstrating Aquinas’s error on this point is not a positive argument in favor of sex stemming from the soul.

Moreover, what we now know about the process of human reproduction seems to favor Aquinas’s position; that sex stems more from the matter than from the soul. We know that material processes that are directed by a gene called the Sex Determining Region on Y (SRY) cause the differentiation of the gonads in the fetus and that this differentiation causes a different endocrine regime that completes the process of sex differentiation, including the development of secondary sex characteristics. The fact that in the vast majority of cases the SRY is on the Y chromosome leads to the rule of thumb that if we have an X/X configuration, then we have a girl, and if we have an X/Y configuration, it is a boy. Even in cases of translocation of the SRY gene to an X chromosome or other unusual situations where SRY is impeded in its expression (e.g., androgen insensitivity), it is still the material configuration of the zygote that determines the sex.

Obviously, Finley is aware of all this. His way to maintain that sex still stems principally from the soul is to suggests that an X/X matter is that which is properly disposed for a substantial form with a female generative power, whereas an X/Y configuration is matter that is properly disposed for a form with a male generative power; each accordingly receives the appropriate form. You might say that God sees that this matter (X/Y configured) is suitable for a soul with a male generative power and so infuses such a soul into it. Finley sees this merely as the application of a more general principle, namely, that when God sees that a certain matter is disposed for a human form (since the matter is the result of the fusion of a human ovum and sperm), he infuses a human substantial form into it rather than some other type of substantial form (such as that of a dog).⁹

I believe that this way of articulating things has some problems. First, it seems to relegate matter to a lower importance in the substance than is necessary. Aquinas’s approach in On Being and Essence might be characterized as “let matter do what matter can do and only appeal to the form if need be.” The color of the body is attributed to the side of matter because matter (by means of inheritance) can account for this: there is a redundancy in making an appeal to the substantial form (or a proper accident of this form). Something similar is true with sex. The paradigm offered by Finley makes matter of too little significance, relegating it to little more than a sign to the Creator as to the appropriate form to create and infuse.

My second observation is that gender development can be redirected at its early stage. It seems that a zygote with an SRY gene could be interfered with so that the SRY gene does not express itself in the development of testes (e.g., by chemically deleting the SRY very soon after conception). This human individual would initially be on a trajectory to become a mature male but could, conceivably, end up as a fertile female. This phenomenon cannot be explained by Finley’s metaphysics but is congruent with the paradigm that I am suggesting because new information in the matter would be “read” (by the generative power) and acted on accordingly.

Finally (and connected with the last point), the paradigm offered by Finley does not fare as well as the paradigm I offer here when it comes to an explanation of the phenomenon of intersexed persons. If the soul is innately female or male, then it is hard to see how a body could ever emerge that is ambiguous. Defective or resistant matter would merely lead to an asexual individual, since in such cases, the soul would be thwarted in developing either female or male organs. However, if the soul is unsexed but the sex is determined by the union of this form with matter, then some ambiguity of information in the matter could well account for the fact that both female and male traits emerge and do so in an imperfect way.

Different Powers Would Mean Different Species

I now need to turn my attention to Finley’s treatment of the objection (to his own position) that were sex to stem from the soul, this really would imply that men and women are two separate species. Finley, as I explained, claims that the generative power is not a reality that could specify the nature of a thing since it is merely ordered to replication of the nature. Hence, a sexed generative power (rooted in the soul) does not make a different species.

But the reproductive power most certainly is specifying in the sense of being a specific power. It is not merely a power to replicate, indifferent to nature, like a Xerox machine. Rather, it is a power ordered to the replication of this (and only this) kind of substance. Just as the nutritive power is not merely a power to maintain a generic substance but is a power to maintain this kind of substance. After all, the nutritive power is tailor-made to the substance: it retains what this substance needs and filters out what is useless or harmful to this substance. Likewise, the generative power is a power ordered to the passing on of a particular nature.

As noted, Finley also seeks to answer this objection by pointing to the fact that the generative power is a “co-power.” His argument implies that the female and male generative powers have the same objective (human generation) and so are not distinct powers in the way that seeing and hearing are distinct by their distinct objects.

To this, I would respond that the generative male and female powers (as conceived by Finley) would be distinct powers because they would have distinct proximate objectives, namely, the fashioning and delivery of ova (female) and the fashioning and delivery of sperm (male). The completion of these distinct activities completes their respective purposes. That this is the case can be seen from the fact that these gametes can then be frozen, thawed, and artificially united to each other in a petri dish; a human life being formed thereby. That these powers are not operative during a process like in vitro fertilization—and yet human generation can still occur—indicates that the production of the gametes (and not human generation itself) marks the completion of each power’s activity.

The fact that these activities are further ordered to bring about something more than each power alone achieves (i.e., the zygote) does not change things. By way of comparison, the telos of the power of sight and the telos of the power of hearing are united in a percept by the power of the common sense,¹⁰ yet each (sight and hearing) has its proper (and specifying) object on account of the respective proximate goal of each power.

By way of contrast, in the paradigm that I am proposing here, the generative power is bipotent and so it does not distinguish male and female as separate species. Moreover, the generative power (as I envision it) is no less generic after developing specialized reproductive organs than before. Yet, on account of the material specialization, the composite now contributes in a specific way to the activity of generation and so the composite is male or female on account of that.

Not a Feminine Soul but Feminization of the Soul

While I do not think that we can speak of feminine souls and masculine souls (neither in truth nor within Aquinas’s metaphysical system), we might be able to speak of a feminized or a masculinized soul. This would seem to be a corollary of Aquinas’s commitment to the notion of body–soul commensuration.

Commensuration is the idea of mutual coadaption of matter and form (Aquinas, Summa Contra Gentiles II 81). There is a two-way street here, so to speak, such that the body leaves its mark on the soul as well as the soul on the body. On account of commensuration, this human soul is adapted to this particular body and could not become the form of another human body. Now, given that all the powers of the soul are rooted in the one same essence of the soul, one would expect that, at the moment of ensoulment, each soul-based power is marked in some way by the particular body that it is the form of. This “marking” would not change the inherent nature of any power (re-specifying it, as it were), but it would give to this power a certain tendency that would otherwise not be there: for example, a propensity of the intellect to be drawn toward certain elements of reality more than others, such as to things rather than to persons.

Aquinas touches on this idea of body-to-soul impact when he discusses how it is that one person is cognitively smarter than another. This is a curious fact, given that both have the same type of intellect. After all, we are not like the angels who each have (or are) a different species of substantial form with a different grade of intellect. Part of the answer to the varying cognitive abilities among human beings is that the intellect uses the body as an instrument for the gathering and processing of sense data. But the first reason Aquinas gives for the variation is as follows:

First, as regards the intellect itself, which is more perfect. For it is plain that the better the disposition of a body, the better the soul allotted to it (quanto corpus est melius dispositum, tanto meliorem sortitur animam); which clearly appears in things of different species: and the reason thereof is that act and form are received into matter according to matter’s capacity: thus because some men have bodies of better disposition, their souls have a greater power of understanding (Aquinas, Summa Theologiae I 85.7).

The phrase “the better the disposition of a body, the better the soul allotted to it” could make it sound as if God foresees the quality of the future body (on account of the matter that is supplied by the parents) and then creates and infuses a soul of compatible quality. Such an interpretation does not seem correct in light of what follows because Aquinas says that “act and form are received into matter according to matter’s capacity.” Here, we seem to have the application of a general principle that act is constrained by potency (Aquinas, Summa Theologiae I 7.1). Hence, it is the quality of the matter (into which the soul is infused) that constrains the actuality of the soul and so delimits the excellence of the intellect.

The basic point is that Aquinas accepts that matter can have a refining affect on the powers of the soul and so one could readily accept (and expect) that a feminine body will tend to refine the intellectual and sensitive powers of the soul in a way that is different from what will occur if a soul informs a male body. I would propose that this idea is really the foundation of what John Paul II calls “the genius of woman” (John Paul II, Mulieris Dignitatem §30). Hence, we truly can speak of a feminization of the soul, but not a feminine soul.

Sex Reassignment Surgery

At the end of his article, Finley very briefly considers the question of sex reassignment surgery. He does not believe that this changes the sex of the individual but rather neuters him or her. However, at least in the article itself, the surgery that he envisages is merely plastic. What if the alteration resulted in sex organs that really could produce and deliver the requisite gametes? While currently not possible, in the future, it might be tenable to produce testes from a woman using her own stem cells. These organs would then be transplanted back into the woman, giving her the power to produce sperm. These would be her sperm, from a genetic point of view.

It seems that even this kind of change would not bring about a change in sex according to the paradigm offered by Finley. In fact, Finley’s paradigm would make this procedure ontologically impossible. After all, there would be no male generative power of the soul to sustain and actualize these new testes.

Would the paradigm that I am defending here come to a different assessment? The scenario under consideration certainly seems to be ontologically possible within this alternative paradigm, in the sense that the generative power of the soul is not sexed and so it remains open to actualize the matter that it has before it. It seems that the soul of the woman could sustain the “manufactured” and transplanted testes.¹¹

Yet, I do not think that such an individual would fully satisfy the definition of a male because the individual would have acquired the capacity to produce sperm rather than having developed it by some entelechy inherent within the individual. At least, this individual could not be called a male in a univocal sense as when it is used for me. After all, I have defined male as “a human individual who has the active potency to develop the organ needed to produce and deliver sperm.” Admittedly, this individual, with artificially generated testes, now has the power to produce sperm, but this power is not the self-unwrapping of an inherent capacity. An analogy would be the transplantation of a human organ, such as a pancreas, into a pig. The pig would now have an ability to produce human insulin. Yet, the pig does not, thereby, become human. It is one thing to be able to sustain an organ, it is another to have the inherent power to generate it.

It is worth noting here that I am affirming (as also is Finley) that sex is (as Aquinas says) a proper accident of the individual which flows from the individuating principle of the human being. On this point, we only disagree as to whether this proper accident flows more from the form or from the matter. Were one to truly change sex in undergoing the suggested procedure, this would entail that sex is not a proper, but a common, accident, and neither of us hold to that.¹²

Furthermore, I would not expect the new testes to have a masculinizing effect on the soul (as is the case at conception), since the commensuration of the form and matter has already happened. It seems that the commensuration of form and matter is the result of what happens at the moment that the soul is infused into the body. This is the moment of mutual impact, so to speak. This would explain why neither a continuous turnover of matter—98 percent of all atoms in a two-year period—nor major organ transplants (Bunzel et al. 1992) affect the temperament of an individual.

Conclusion

Here, I have sought to show why I am in general agreement with Aquinas in the way that he positions sex. By “general agreement,” I mean that sex is a proper accident of the human individual and that it is determined by the matter more than by the substantial form (the soul) or any accidental form of the soul. Sex relates to the power to generate and to the specific ways in which the female and male contribute to generation. This power is rooted in the soul, but whether this power is actualized in the mode of the male or the mode of the female is determined by the matter to which the soul is united and material processes that are linked to this. The alternative position that sex stems principally from the soul is not compatible with what we know about the biological development of sex nor with higher-level metaphysical principles such as the unity of man and woman as the two expressions of the one same human species.

Biographical Note

William Newton, PhD, is a professor of theology at Franciscan University of Steubenville, OH. He worked for ten years in scientific research before turning to the study of theology. From 2005 to 2012, he was an assistant professor of theology at the International Theological Institute in Trumau, near Vienna, Austria. He is an associate member of faculty at Maryvale Institute in Birmingham, UK, and founding member of the Aquinas Institute of Ireland. He has his PhD from the John Paul II Institute in Australia, an STL from the Leuven (Belgium), and an MTS from the International Theological Institute. From 2013 to 2017, he was a chair of faculty at Franciscan University’s Gaming semester abroad program. He has published in numerous journals including Anthropotes, Josephinum Journal of Theology, The National Catholic Bioethics Quarterly, The Linacre Quarterly, The New Oxford Review, Homiletic and Pastoral Review, Inside the Vatican, Journal of the International Academy of Marital Spirituality, Crisis Magazine, The Furrow and the Catechetical Review (formerly The Sower). He is the author of an introduction to Catholic social teaching entitled, A Civilization of Love: The Catholic Vision for Human Society (Gracewing, 2011). He is originally from England. He and his wife Claire have five children.