Natural law proponents use Aristotle and Aquinas to argue against ideas like gay marriage. Here, Gunther Laird takes aim at their defenses.

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My first book, The Unnecessary Science, has previously been reviewed and discussed here at OnlySky. It gives a philosophical and critical look at the thinking of Aristotle, Thomas Aquinas, and then modern religious thinkers like Ed Feser who build on those foundations to make moral proclamations in line with their theistic beliefs.

The book has started to attract some weightier critiques, with some coming from Justin Kalan of The Molinist. It is important to deal with such thinking and criticisms because Thomism, natural law, and other similar philosophies underwrite conservative, religious legal approaches to subjects like abortion, gender, and sexuality.

Mr. Kalan has thus far made three posts dealing my book at themolinist.org, so my responses will be split into three sections. The first two, involving my arguments for gay marriage and the permissibility of non-procreative intercourse, will be relatively brief; the objections to those Mr. Kalan raised can be easily dealt with. However, his objections to my defense of abortion are somewhat weightier and also relate to a small error in phrasing that I overlooked in my revision of the final drafts of the book, so the third section of my response will be slightly larger.

“Forms” and gay marriage

In The Unnecessary Science, I claim that even within the Aristotelian framework Catholic “natural law” proponents use to decry homosexuality and gay marriage, it is possible to reach the exact opposite conclusion that they propose. Let me introduce what Form means in the context of this subject:

Even better, we’ve just found what Plato, Aristotle, Aquinas, and their intellectual descendants called the “Form” of these things. A Form, (or an Essence), is what defines a thing and distinguishes it from everything else. The specific wavelengths of light associated with green define it and distinguish it from other colors, and the equidistance of all points on its surface from its center defines a sphere and distinguishes it from other shapes. Now, it’s not just colors and shapes that have Forms. According to natural law adherents, everything has a Form. Concepts (there’s something that defines justice and distinguishes it from tyranny), artifacts (there’s something that defines a PlayStation 5 and distinguishes it from a Game Boy), and even living things (there’s something that defines a human being and distinguishes her from a squirrel or jellyfish).

The Unnecessary Science, p. 44-45.

Since the Aristotelian claims that institutions that help us fulfill Forms are legitimate and unobjectionable, I claim that if homosexuals instantiate a certain Form, then gay marriage allows them to fulfill the needs entailed by that Form and is thus legitimate and unobjectionable from an Aristotelian point of view.

Mr. Kalan disagrees, claiming I have overlooked the difference between substantial and accidental Forms. In this post, he states the following:

A substantial form is the form which constitutes any natural substance, i.e. it is what makes a substance what it is by giving it an intrinsic principle of operation… For anything that has a substantial form however, it has only one substantial form. A squirrel has the substantial form of a squirrel. That’s what makes it a squirrel. On the other hand, a squirrel might have other accidental forms e.g. the color of its fur might be this or that shade of brown or have this or that texture. These forms do not change what the squirrel is–a squirrel–and thus don’t change what end the squirrel has. An equivalent example in humans would be some people having the form of blonde hair, or having a certain skin color for example. Such forms are accidental to any person. That is, they could be different but the person would still be the same person. Whether someone has blonde hair or black hair, they are still the same kind of thing, namely a person… Is homosexuality a substantial form? Obviously not since all homosexuals are still human persons. Thus, they still share the same substantial form. Homosexuality then, insofar as we think of it as a form, is an accidental form, which does not define what kind of thing a person is and which does not affect a person’s end…Thus, Laird’s conclusion that a homosexual person’s different form implies their sexual faculties are ordered to a different end cannot be correct.”

This objection fairly quickly fails when we realize that “substantial” Forms can exist in a nested manner among other “substantial” Forms within an Aristotelian framework. The most obvious example that comes to mind is sex in humans, at least if you’re Catholic. Both men and women share the same “substantial” Form of Humanity (Aristotelians generally and Catholics specifically would say this is actually “Rational Animality,” but we can leave that aside for now). However, as Catholics incessantly tell us, it is also the case that men and women are two distinct types of human being, both substantially possessing different ends in some respects while having the same one in others. That is to say, the Catholic would claim that men and women substantially have the same end in one respect (worshipping God), but their various faculties, especially sexual, have different ends in other respects: Men are “ordered” by their substantial Form to ejaculate, whereas women, by contrast, are “ordered” by their substantial Form to gestate, and so on.

This might seem like a bit of digression, so let me tie it directly to my point. If you accept the idea that a substantial Form can entail in itself at least a few substantial sub-Forms (and as the example of sex above demonstrates, a Catholic at least must concede this) then my Aristotelian argument for gay marriage remains undefeated. I merely have to establish that just as the substantial Form of Humanity can be divided into the substantial Forms of Man and Woman, those two substantial sub-Forms can themselves be divided into the substantial sub-sub-Forms of Straight Men, Gay Men, Straight Women, and Gay Women, and therefore gay marriage fulfills the substantial Form of Gay Men and Gay Women.

Now, Mr. Kalan states that homosexuality must be an accidental rather than a substantial Form:

Consider the fairly widely accepted fact that some people’s sexuality changes over time. For Laird’s position to be correct, such a change meant that the person whose sexuality changed underwent substantial change (i.e. change in substantial form). This means that they ceased to exist and became a different kind of thing! Obviously such a view is absurd.

This actually doesn’t strike me as a “fairly widely accepted fact.” One of the strongest arguments gay-rights advocates have in their arsenal is the amount of evidence for sexuality being fairly rigid and difficult to change in most circumstances, indicating that homosexuality is an identity rather than some sort of “lifestyle choice.” For instance, see the following:

In 1991, the author of an early comprehensive examination of conversion therapy concluded: “There is no evidence from any of the studies reviewed here to suggest that sexual orientation can be changed.” Nearly 20 years later, in 2009, a task force of the APA conducted a systematic review of the peer-reviewed journal literature on sexual orientation change efforts, particularly during more recent years. The task force noted a dearth of scientifically sound research on the safety of sexual orientation change efforts (SOCE), “because no study to date of adequate scientific rigor has been explicitly designed to do so.” Relying on the few studies it deemed “true experiments or quasi-experiments,” all conducted from 1969 to 1978, the task force concluded that it is “unlikely that individuals will be able to reduce same sex attractions or increase other-sex sexual attractions through SOCE.” The APA resolved “there is insufficient evidence to support the use of psychological interventions to change sexual orientation.” Mainstream mental health organizations support this conclusion. MDH did not find scientific studies to support the effectiveness of conversion therapy practices.

Minnesota Department of Heath, Summary of Findings: A Review of Scientific Evidence of Conversion Therapy, EXECUTIVE ORDER 21-25

Perhaps Mr. Kalan is referring to changes in sexuality that occur as we age. This strikes me as proof that one’s substantial Form can be hindered in its expression by the process of aging, not that one’s sexuality is merely accidental. For instance, a Catholic opponent of gay marriage would say that men and women are substantially “ordered” to be attracted to each other, and the decline in sexual desire many men and women feel as they get older is simply an unfortunate side effect of the body aging. That is to say, no substantial change in Form has occurred, one is simply less able to fulfill an aspect of their substantial Form.

If one regards substantial Form in humans dividing between sexuality within the sexes (much as sex divides the substantial Form of Humanity), then apparent differences in one’s sexuality over time can be chalked up to aging interfering with the proper expression of a substantial Form. The Aristotelian gay-rights proponent can still hold that sexuality is indeed a marker of a “substantial” Form, and can continue to argue for gay marriage based on that ground.

Hopefully, this has broken down some more complex thinking and argumentation relating to real-world, modern societal situations into something more digestible.

The arguments are more prevalent than one might think. They pervade certain religious communities and underwrite the work of those involved in making law who adhere to natural law principles.

In future pieces, I will discuss abortion, nocturnal emissions, and the end of sex. For many, these are important philosophical considerations.

Gunther Laird is a freelance scholar working in the United States. The Unnecessary Science is his first book, with it hopefully to be followed by others in a similar vein.

A TIPPLING PHILOSOPHER Jonathan MS Pearce is a philosopher, author, columnist, and public speaker with an interest in writing about almost anything, from skepticism to science, politics, and morality,...

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