Gunther Laird recently authored the book The Unnecessary Science: A Critical Analysis of Natural Law Theory which is a critique of Edward Feser’s account of natural law. Throughout the book Laird attempts to show that even if one accepts Feser’s account of natural law, such an account is compatible with various positions which Feser himself would repudiate. Laird argues that same sex marriage, abortion, slavery, and other things which Feser would reject are quite compatible with Feser’s own natural law theory. In this essay I will look at Laird’s argument regarding same sex marriage and show why his argument fails.

Laird’s Argument

Laird first argues that homosexual persons have a different form than heterosexual persons:

A Form is what ‘defines and distinguishes’ any given object or concept from anything else…Given this, it seems reasonable to assume that gays and lesbians participate in the Form of Homosexuality, which differentiates them from heterosexuals.

The Unnecessary Science pg. 139

Since they have a different form, Laird claims that, on Feser’s metaphysics, what is good for them might be different than what is good for a heterosexual person.

If gay people have their own particular Form, it also stands to reason that what is good for them may actually be different than what is good for heterosexual people. After all, the good, in the sense of fulfilling one’s function, is different for creatures with different Forms. To re-use Feser’s favorite example, it is good for a squirrel to scamper up trees and nuts but it would starve if it tried t visit many flowers and eat pollen.

The Unnecessary Science pg. 140

Laird then concludes that because homosexuals have a different form and what is good for them is different, that “perhaps the final cause of a homosexual’s sexual faculties is something different [than procreation], like social bonding”. What can we make of this argument?

Substantial and Accidental Forms

Laird’s argument that because homosexual people have a different “form”, their faculties are ordered toward a different end is based upon a failure to distinguish substantial and accidental forms. 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. A squirrel, to use Laird’s quote, has one substantial form while a bee has yet another. These are two different kinds of substances and therefore have different ends. What makes something a good squirrel is quite different from what makes something a good bee as Feser was noted as saying.

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. Indeed such things (e.g. hair color) change in a single person over time and yet the person remains the same.

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. 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.

Thus, Laird’s conclusion that a homosexual person’s different form implies their sexual faculties are ordered to a different end cannot be correct. Such faculties have their end because of the kind of thing they belong to which in this case is a person. Whether that person has this or that desire even if it were by birth is irrelevant to the end of such faculties. Laird needs homosexuality to be a substantial form and it is not.

Laird makes other related arguments about sexual faculties in the same chapter of the book and I hope to address those as well.