Overview of the Perverted Faculty Argument
The perverted faculty argument asserts that the sole morally permissible use of the sexual faculty is within non-contracepted heterosexual acts between married spouses. Any deviation from this use is considered contrary to the faculty's inherent purpose and, therefore, constitutes a perversion. This perspective is elaborated in sources such as the Faith Magazine article on sexual morality, which outlines the argument's foundational principles.
Key Critiques of the Argument
Questioning the Moral Relevance of Biological Functions
Paul J. Weithman, in Natural Law, Morality, and Sexual Complementarity, challenges the moral significance of biological functions:
"It is hard to see why facts about the natural functions of the reproductive organs are even morally relevant, let alone morally decisive. To suppose they are morally decisive is to suppose that there can be cases in which the intentions of agents are irrelevant to the moral worth of an act. It is to repose the moral worth of those acts in their physical properties."
Emphasis on Intention Over Physical Acts
Arthur Schopenhauer, in The Two Fundamental Problems of Ethics, emphasizes the primacy of intention:
"The intention alone decides on the worth or unworth of the deed, which is why the same deed, according to its intention, can be reprehensible or praiseworthy."
Challenges to Deductive Rigor
Catholic moral philosopher John Montgomery Cooper, as quoted by Leslie Woodcock Tentler in Catholics and Contraception: An American History, questions the deductive rigor of the natural law argument:
"Just precisely how are we going to formulate such a definition of the natural function of the reproductive faculty as will permit relations in pregnancy and sterility and yet bar contraceptive practices? And after we have succeeded—if we succeed—in so formulating this function, just precisely what concrete objective evidence are we going to muster to show that our formulation, and no other, represents the true function?"
Alexander Pavuk, in Catholic Birth Control?, reinforces this critique:
"Cooper targeted the deductive 'perverted faculty' argument by saying that Catholic authorities have offered 'facile assumptions' in place of 'objective evidence' as to 'what precisely is the natural function of the faculty (sex) under consideration?'"
Robin Gill, in A Textbook of Christian Ethics, further contends:
"Even if it is conceded that procreation is the obvious function of sexuality, it is far from clear that it should be the only, or the indispensable, function of human sexuality."
Contextual Variability of Natural Functions
A central question arises: Can a natural faculty possess distinct primary purposes depending on context or circumstances? Might varying situations yield different obligatory ends, with a purpose mandatory in one scenario becoming optional in another? Thomists must demonstrate why such contextual variability is definitively impossible.
Agustín Fuentes, in Race, Monogamy, and Other Lies They Told You, notes:
"Our sexual pair bonding, like our sexual activity, is not limited to reproduction. [...] Even in our closest evolutionary relatives, the apes, it is only recently that we have come to realize that sexual behavior is common, not always related to reproduction, and complicated."
Peter Vardy, in The Puzzle of Ethics, questions functional assignments:
"For instance, is the purpose of a mouth for eating or for kissing or for both? Who is to decide? If kissing is part of the function of mouths, then kissing would become a good rather than, arguably, an evil. The need to make assumptions which may be challenged is, therefore, implicit in Aquinas’ whole approach and weakens its effectiveness."
Mel Thompson, in Understand Ethics: Teach Yourself, expands on definitional challenges:
"How do you decide what is ‘natural’? Science bases its ‘laws of nature’ on observation, and they claim to be no more than an interpretation of the best available evidence. If something is observed that does not fit in with an established law, then either the observation is inaccurate, or another (as yet unknown) law has unexpectedly come into operation. Our understanding of the way in which nature works is therefore constantly being modified. If this also applies to ‘natural law’ as an ethical theory, then we cannot establish fixed criteria for right and wrong—which was the aim of Aquinas and others who followed this line of thought—because our concept of what is natural, and therefore of ‘final causes’, will always be open to modification. It is natural for someone who is seriously ill to die. Does that mean that one should not interfere with the natural course of a disease by giving medicine? In the natural world, the strongest animals often mate with as many sexual partners as they can, fighting off weaker rivals. Should there be selective breeding among humans? Is monogamy unnatural? These examples suggest that there is no easy way to establish the ‘final cause’ that will enable us to say with certainty that we know exactly what every thing or action is for, or what part it has to play in an overall purposeful scheme of the universe."
Christopher Arroyo, in Natural Goodness, Sex, and the Perverted Faculty Argument, argues:
"The relief of sexual tension, practicing safe sex, greater awareness of one’s sexual preferences, alleviating sexual dysfunction, marital satisfaction, and increased self-esteem are all genuine human needs in the human life-form, none of which (except perhaps the first) are needs in other species of animal. These needs indicate some of the ways in which human sexual activity, like human eating, is inextricably bound up with the various physical, psychological, social, and cultural features of the human life-form that make the role of human sexual activity enormously different from the role sexual activity plays in other species. These needs also point more generally to why some intrinsically nonprocreative human sexual activity can contribute to human flourishing: given the human life-form, sex for human beings is not merely for reproduction. [...] Feser’s understanding of the natural ends of sexual activity fails to grasp adequately what is unique about the human life form and its corresponding natural good."
Harry J. Gensler, in Ethics: A Contemporary Introduction (Chapter 13), critiques:
"Critics object that it needn’t be wrong to use organs for something other than their primary biological purpose; for example, there’s nothing wrong in using our feet to kick a football. So it needn’t be wrong to use sex organs for something other than their reproductive functions."
Illustrative Examples Highlighting Inconsistencies
Artificial Insemination and Procedural Adherence
Thomas Aquinas's theory influences modern prohibitions, such as the 1987 Vatican Congregation for the Doctrine of the Faith's stance on artificial insemination:
"Homologous artificial insemination within marriage cannot be allowed."
An exception permits semen collection via a perforated condom during intercourse, preserving the form of a natural generative act without impermissible contraception. The act must simulate potential procreation, even if infertile. Uta Ranke-Heinemann, in Eunuchs for the Kingdom of Heaven: Women, Sexuality, and the Catholic Church, observes:
"The supposedly natural act has become the first commandment and it has kept that status even when its original goal, as prescribed by the Church, procreation, cannot be reached at all, and when obtaining semen through masturbation would be just as good a method, or a better one, because it is less complicated. But masturbation still ranks with the most serious, unnatural sins of contraception, even here when it is precisely being used to make conception possible. The standardized procedure has become more important than the goal, namely procreation. What is 'natural' is determined by old traditions, and such traditions are carefully protected by old male celibates."
Natural Family Planning vs. Mechanical Contraception
Natural family planning (NFP), once disallowed by Church Fathers, is now permitted as a contraceptive method among Catholics, while condom use remains sinful. Yet, the intent behind both practices—to avoid conception—is identical. Protestants often view NFP and mechanical contraception as ethically equivalent. As noted, a deity distinguishing morally between these methods would appear overly meticulous, particularly given NFP's superior efficacy per the Pearl Index.
Analysis of Feser's Thomistic Framework
Edward Feser's interpretation of Thomistic natural law employs distinctions between actions "contrary to" and "other than" natural ends. To enhance systematic coherence, one might incorporate "in accordance with" as a complementary term: actions contrary to nature are morally evil, those in accordance with it are morally good, and those other than it are morally neutral.
For instance, eating breakfast or bathing aligns with human nature and is thus morally good. If kissing is a natural function of the mouth and tongue, it too yields moral value. Conversely, obtaining a semen sample via masturbation for medical purposes (e.g., cancer diagnosis or infertility assessment) would be morally evil as contrary to nature. Chewing gum exemplifies moral neutrality: it uses the digestive system differently from its primary function, without direct contravention, despite potential futility or strain.
However, Feser's distinction between "contrary to" and "other than" remains elusive. In both, the natural end is deliberately avoided, yet only the former incurs moral evil. Even John Skalko, an intellectual ally in Disordered Actions, finds it untenable:
"Feser relies upon an unclear account of contrary use and other than use, which is either ad hoc or cannot grant him the conclusion he desires."
If this distinction collapses, Feser's natural law framework falters: either innocuous acts like chewing gum or hand-walking become morally wrong, or previously condemned actions revert to moral neutrality.
Analogies Illustrating Inconsistencies in Natural Function
David Bradshaw, in What Does it Mean to be Contrary to Nature?, questions the consistency of deeming certain uses "contrary" to nature:
"Presumably, the natural function of the ambulatory system is locomotion. Does not one who walks on a treadmill use this system in a way contrary to its natural function? Walking on a treadmill seems a rather precise parallel to having sex with a condom, for it involves performing the very act of walking while ensuring that its natural result, movement from one place to another does not occur. Or consider the respiratory faculty. Presumably, its natural function is to deliver oxygen to the bloodstream. People (or boys, at any rate) often enjoy inhaling helium because of the way it makes their voices absurdly high-pitched. Is this an unnatural use of the respiratory faculty? One might answer that it is not, because on the next breath they can always go back to inhaling normal air. But of course the same can be said of masturbation; it too uses a natural faculty for something other than its natural end without in any way preventing that faculty from performing its natural function the next time it is used."
The Is-Ought Distinction and Normative Derivations
David Hume's is-ought problem posits that prescriptive moral claims cannot logically follow from descriptive facts alone. Kai Nielsen, in Atheism and Philosophy, articulates:
"Natural moral law theorists confuse talking about what is the case with talking about what ought to be the case. They confuse de jure statements with de facto statements. A statement about what people or what normal people seek, strive for or desire is a factual, non-normative statement. From this statement or from any conjunction of such statements alone no normative (de jure) conclusions can be validly deduced except in such trivial cases as from 'He wears black shoes' one can deduce 'He wears black shoes or he ought to be a priest.' But this simply follows from the conventions governing the disjunction 'or.' Moreover, because it is a disjunction it is not actually action-guiding; it is not actually normative. To discover what our natural inclinations are is simply to discover a fact about ourselves; to discover what purposes we have is simply to discover another fact about ourselves, but that we ought to have these inclinations or purposes or that it is desirable that we have them does not follow from statements asserting that people have such and such inclinations or purposes. These statements can very well be true but no moral or normative conclusions follow from them."
David Bentley Hart, in Is, Ought, and Nature’s Laws from A Splendid Wickedness and Other Essays, elaborates:
"Even if one could exhaustively describe the elements of our nature, the claim that we are morally obliged to act in accord with them, or to prefer 'natural' uses to 'unnatural,' could be made only as something additional and adventitious to the whole ensemble of facts that this description would comprise. Otherwise we could not see it as a moral good at all, but only as a negotiable feature of private taste. The assumption that the natural and moral orders are connected to one another in any but a purely pragmatic way must be of its nature antecedent to our experience of the world. I know of many stout defenders of natural law who are quick to dismiss Hume’s argument, but who—when pressed to explain themselves—can do no better than to resort to a purely conditional argument: if one is (for instance) to live a fully human life, one must then . . . (etc.). But, in supplementing a dubious 'is' with a negotiable 'if,' one certainly cannot arrive at a morally categorical 'ought.'"
Hart further critiques Edward Feser's defense in Nature Loves to Hide from the same volume:
"The most gallant of Feser’s non sequiturs is his claim that, because reason necessarily seeks the good, there exists no gap into which any Humean distinction between facts and values can insinuate itself. But obviously the gap lies in the dynamic interval between (in the terms of Maximus the Confessor) the 'natural' and 'gnomic' wills. The venerable principle that the natural will is a pure ecstasy toward the good means that, at the level of gnomic deliberation, whatever we will we desire as the good, but not that philosophical theory can by itself prove which facts imply which values, or that the good must naturally be understood as an incumbent 'ought' rather than a compelling 'I want.' Feser asserts that 'purely philosophical arguments' can establish 'objective true moral conclusions.' And yet, curiously enough, they never, ever have. That is a bedtime story told to conjure away the night’s goblins, like the Leibnizian fable of the best possible world or the philosophe’s fairy tale about the plain dictates of reason."
An anonymous commentator notes:
"Feser claims that he does not have an 'is-ought' problem. Maybe so, but he has merely replaced it with a 'nature’s End - ought' problem that is equally tenacious. He still faces the question of 'So nature intends that I X. But why should I X?' Seems to me he has gained nothing from that move."
Sources of Normativity and the Role of Will
Critics argue that normative obligations stem from wills—either one's own or another's—rather than impersonal natural facts. In German linguistic analysis, the verb "sollen" (ought/should) implies a personal agent demanding action. For example, a doctor's prescription creates an "ought" based on their directive. Natural faculties, however, lack this personal agency, rendering them incapable of generating moral imperatives.
If natural law invokes God as the demanding will, this raises issues of divine communication. A philosophical skeptic, influenced by Hume or Fritz Mauthner (as cited in On Fritz Mauthner's Critique of Language by Gershon Weiler), might view natural "laws" as human projections:
"The so-called 'laws' of the natural sciences originate in man's preference for order, but not from nature itself. There is nothing corresponding to them in nature. The same criticism applies to the concept of 'aim' in nature, which M[authner] takes, with Spinoza, to be only an analogy to human intention."
Mel Thompson, in Understand Ethics: Teach Yourself, emphasizes:
"To get an absolute command (or ‘categorical imperative’, as we shall see later) you have to presuppose someone who gives that command. Within the natural law theory, as it has developed since the time of Aquinas, that ‘someone’ is God. This gives its moral pronouncements an authority that may not be justified by the logic on which the argument is based."
L.A. Rollins, in The Myth of Natural Rights, suggests natural law often masks personal preferences:
"As I’ve said, natural laws and natural rights are inventions intended to advance the interests of the inventors (whom I shall call 'natural legislators'). What is often involved is an attempt to manipulate other people into behaving as desired by a natural legislator, by duping them into accepting the values of the natural legislator as the values of nature. Thus, the personal, subjective preferences of a natural legislator are passed off as the impersonal, objective requirements of nature. For example, Frederick D. Wilhelmsen writes that, 'Natural law insists that pornography … is bad and that it is bad not just for me, but for everybody, and it equally insists that not only must I not invade my neighbor’s property but that he must not invade mine or anybody else’s.' In other words, Frederick Wilhelmsen insists that pornography is bad for everybody, and he equally insists that no one must invade anybody else’s property. But in order to give his personal preferences greater authority, Wilhelmsen pretends that it is nature who is doing all the insisting."
Alternative normativity arises from personal goals (hypothetical imperatives), as in: "I want to be home at ten o'clock, so I must take the bus at half past nine." Thompson notes a parallel in Eastern philosophy:
"In Eastern philosophy, the idea of karma—that actions have consequences that cumulatively influence the future—relates the state of the world to moral choices. But this gives only a 'hypothetical' command (in other words, one that says 'If you want to achieve X, then you must do Y'), not an absolute moral command."
Elective Priorities and Hierarchical Values
David Bentley Hart, in Is, Ought, and Nature’s Laws, addresses the challenge of prioritizing values:
"Elective priorities. Assume, however, that we can establish the existence of a moral imperative implicit in the orderliness of the world, as perceived by a rational will that, for itself, must seek the good: Does that assure that we can prove what hierarchy of values follows from this, or how we should calculate the relative preponderance of diverse moral ends? Yes, we may all agree that murder is worse than rudeness; but, beyond the most rudimentary level of ethical deliberation, pure logic proves insufficient as a guide to which ends truly command our primary obedience, and our arguments become ever more dependent upon prior evaluations and preferences that, as far as philosophy can discern, are culturally or psychologically contingent. Consistent natural law cases can be made for or against slavery, for example, or for or against capital punishment, depending on which values one has privileged at a level too elementary for philosophy to adjudicate. At some crucial point, natural law argument, pressed to disclose its principles, dissolves into sheer assertion."
Theological and Denominational Dependencies
Thomistic natural law is inherently tied to Catholic theology. Without belief in God and Church teachings, it lacks grounding. Mark D. Jordan, in The Ethics of Sex, affirms:
"[...] Thomas knew as well as any medieval theologian that human societies disagree sharply about how human beings ought to act. He himself mentions cases in which whole societies teach their members to do things that he thinks contrary to natural law. Given the diversity of societies, the contradictions in the history of moral conventions, is there any kernel of natural law that every human being shares? Perhaps there is, but that kernel will not be enough to direct us individually or to make us agree collectively. In practical matters, agreement about principles and about the shape of moral reasoning is no guarantee of agreement about practical conclusions. Indeed, the more particular the case, the more difficult it is to arrive at a conclusion on which all will agree. Alternately, the more specific a norm or precept proposed in ethics or law, the more liable it is to justified exception. In many particular cases, the right course of action cannot be regularly agreed, even among virtuous people. This insufficiency of natural law becomes the starting point for Thomas's arguments in the Summa on the need for divine law, that is, for an explicit teaching about human conduct revealed by God. Because natural law participates in God's eternal plan only 'according to the proportion of the capacity of human nature,' God generously teaches a more articulate law, the divine law that is eminently contained in the Old and New Testaments. We are able to 'fulfill' the natural law only after God's revelation. The content of natural law only becomes clear with the handing down of the Old Law, the law of Moses. The content of natural law only becomes practicable with the gift of grace in the New Law—whether we are talking about justice or about 'unnatural' sex. Many of the 'natural law' arguments we hear today do not rise to the level of misreadings of Aquinas. They are rather loud assertions pretending to be common sense or, what is worse, natural science. But even in more serious efforts to make 'natural law' arguments against certain sexual acts, we can hear how easily Christian theology can slip from rich conceptions of law as divine self-disclosure to poor conceptions of law as imposed ideology or criminal code. [...] The difficulty we now feel in speaking convincing arguments about 'unnatural' sex cannot be blamed on just the growth of modern medicine or the spread of liberal notions about self-fulfillment. We understand it better as a loss of the grand Christian rhetorics within which sin-identities made sense of acts by organizing them. When we try to pull the acts away from the identities, we find that they don't make much sense. Of course they don't. They never did without identities. This loss of coherence in specifying 'unnatural' acts is closely connected to the loss of conviction produced by appeals to natural law. Christian condemnations of unnatural acts were not meant to work without Christian sin-identities; arguments from natural law were not meant to work outside of an ideal pedagogy of virtuous family, just city, and luminous divine revelation. Natural law arguments about sex are not detachable from the Christian narrative of a progressive divine teaching through history."
This dependency traces to patristic views on Eden, as noted by Reddit user Quidfacis_:
"It might help to read Aquinas and Augustine's take on progeneration in the Garden of Eden to understand why, historically, the sexual members have such specific functions. The predominant view of the time was that either there would have been no procreation, or procreation would have occurred through some divine means. This because sexuality is bound up with lust, and lust is naughty. Aquinas and Augustine argue against the view by claiming that sex would have recurred without stirring the loins through lust."
Evolutionary and Contextual Challenges to Thomistic Natural Law
The Impact of Evolution on Fixed Purposes
Thomistic natural law presupposes fixed essences and purposes derived from reason's interpretation of final causes. However, this framework encounters difficulties when confronted with modern understandings of evolution, constant change, and contextual variability in natural functions.
Mel Thompson, in Understand Ethics: Teach Yourself: Making Sense of the Morals of Everyday Living, articulates:
"If the whole world is in a state of constant change; if galaxies are moving outwards towards an unknown future; if stars are born and die, and planets spinning around them are vulnerable to their death and many other cosmic accidents; if life on planet Earth is a recent phenomenon and subject to a process of evolution – how can the purpose or goal of anything be fixed? The natural law approach is based on the idea that reason can interpret the essence, purpose and ‘final cause’ of things. We need to consider whether this is compatible with a world viewed from the perspective of evolution and change. Is morality the result of deliberately going against our basic instincts, as suggested by Richard Dawkins at the end of The Selfish Gene: ‘We alone on earth can rebel against the tyranny of the selfish replicators’? Or is some sense of morality genetically programmed into us? Research on the behaviour of apes suggests that there may be the basics of morality – in the attitude of groups to individuals, and the support given by one individual ape to another. So, for example, animals that fight can ‘make up’ afterwards. Is this programmed into them in order to help the species survive in a competitive environment?"
If evolutionary theory holds, organic entities lack metaphysically fixed Aristotelian forms at the species level. For instance, a squirrel's traits result from brutal natural selection, with each generation potentially undergoing alterations that influence successors. Change is inherent to generational continuity. Humanity, having emerged through an amoral evolutionary process, cannot be viewed as possessing a timeless metaphysical essence—including assumptions of exclusive heterosexuality—as an ethical template. Nature's fluidity in evolution contrasts sharply with natural law's rigidity, rendering the latter unsuitable as a stable moral standard. Evolution encompasses not only physical forms but also behaviors and inclinations, necessitating their inclusion in any assessment of biological functionalities.
David Bentley Hart, in Is, Ought, and Nature’s Laws from A Splendid Wickedness and Other Essays, further critiques:
"Even if final causality in nature is demonstrable, does it yield moral knowledge if there is no clear moral analogy between natural ends and the proper objects of human motive? For Thomas Aquinas, only a moral disorder can make one claim ignorance of the reality of the God who, as the source of one’s being, is supremely worthy of love. True in principle, of course. Even so, the 'failure' to find a moral dimension in one’s intrinsic ontological contingency may not be entirely culpable. Our modern narrative of nature is of an order shaped by immense ages of monstrous violence: mass extinctions, the cruel profligacy of an algorithmic logic that squanders ten thousand lives to fashion a single durable type, an evolutionary process that advances not despite, but because of, disease, warfare, predation, famine, and so on. And the majestic order thus forged? One of elemental caprice, natural calamity, the mercilessness of chance — injustice thrives, disaster befalls the innocent, and children suffer. Why, our deracinated modern might ask, should we believe that nature’s organizing finality, given the kinds of efficient causes it prompts into action, has moral implications that command imitation, obedience, or (most unlikely of all) love?"
Teleology, Functionality, and Contextual Variability
Thomists posit teleology or final causality as sufficient for natural law ethics. Critics may deny objective teleology outright or argue it is merely necessary but insufficient, leaving room for debate on human specifics. Thomists assume natural entities have a single primary purpose, a dogma traceable to Aristotle, whose view of eternal species constancy influenced biology but conflicts with evolution's emphasis on habitat context.
This dogma may violate Aristotle's principle that human artifacts mirror natural structures ("art imitates nature"). Natural faculties resemble versatile tools, such as a hammer designed for pounding nails but usable for cracking nuts without moral fault. As noted in an analysis from faculty.cbu.ca:
"A hammer may have been designed to pound nails, and it may perform that particular job best. But it is not sinful to employ a hammer to crack nuts if I have no other more suitable tool immediately available. The hammer, being a relatively versatile tool, may be employed in a number of ways. It has no one 'proper' or 'natural' function."
J. L. Ackrill, in Aristotle the Philosopher, observes Aristotle acknowledging dual essential purposes in organs, such as the elephant's trunk for breathing and feeding in swamps, or another case where one job holds higher order. This suggests contextual dependency, contradicting the single-purpose dogma. If organs can serve two equally primary functions, the same may apply to faculties.
Graham Priest, in Sexual Perversion, addresses evolutionary functionality:
"First, it is no part of a modern notion of functionality that a function is unique. Some organ may well be involved in different uses, each of which gives, or has given, its possessor an evolutionary advantage. In particular, then, the mere fact that the genitals are involved in conception does not mean that they do not have other important functions. It is not incredible to suppose that the giving and receiving of pleasure is one of these. [...] Second, and relatedly, behaviour patterns traditionally reckoned as perverse are hardly modern ones. They are long-standing and widely spread through sections of the population. [...] This suggests (though, of course, it by no means proves) that at least some of them may well have been selected for evolutionarily. If such a behaviour pattern is genetically based, this is, presumably, the case. Notoriously, for example, some sociobiologists have argued that homosexuality is a genetic disposition, and that homosexuality makes perfectly good sense as a strategy for facilitating certain gene transmissions. I certainly do not want to endorse the sociobiological account of homosexuality. I mention it simply to demonstrate that in the light of modern science, it makes perfectly good sense for things counted traditionally as perversions to be functional. Third, and again relatedly, according to both accounts that we looked at, a functional trait may cease to give an evolutionary advantage if the environmental context changes: witness the dinosaurs. (According to the dispositional account, the trait in question then ceases to be a function.) Now, one of the most salient features of the current human environment is the imminent threat of over-population and the consequent environmental disaster. Such an event would doubtless have consequences for the human gene pool - possibly even destroying it. Hence, assuming that it is unrealistic for most people to become celibate, increasing non-procreational sexual activity may well be an evolutionarily sensible strategy in the present context."
Priest adds:
"[T]here is nothing wrong per se with using something for other than its Darwinian biological function. For example, whether one gives an aetiological or a dispositional account of function, body hair may plausibly be supposed to have various functions (protection from the sun, holding body-secretions close to the skin). Yet there is nothing wrong with shaving one's head or armpits and using the hair for something else. Similarly, a function of certain body secretions is to form an infection-protective coating for the skin; but there is nothing wrong with washing frequently (and using the secretion-infused result to water the flowers)."
Christopher Hamilton, in Alexander Pruss on Love and the Meaningfulness of Sex, concurs:
"Our organs are not for anything, and they have no function or purpose: they do what they do, well or ill. Still less does the human body have a purpose or function; it is not for anything. That, of course, is one of the conclusions to be drawn from evolutionary theory. [...] In any case, even if we could say unequivocally what the purpose of any given organ is, we cannot conclude that we ought to use it for that purpose, still less that we ought to use it only for that purpose. That just does not follow. If our hands had the purpose of manipulating objects, it would not follow from that that we ought to use them for that or that we ought not to use them for other things. [...] If the sexual organs are for reproduction, it does not follow that they ought to be used for this purpose, not even if we grant that they may or even ought also to be used for other purposes. This no more follows than it follows from the fact (if it is a fact) that human teeth and digestive system are for the consumption of animal flesh (amongst other things) that we ought to eat meat. You cannot refute vegetarianism so easily."
Historical Misconceptions and Holistic Critiques
Natural law's sexual ethics historically rested on outdated views, such as semen containing the full potential person, equating non-procreative acts to near-homicide. Anthony Kenny, in Medieval Philosophy, explains:
"Aquinas is often invoked in contemporary discussions of the morality of contraception and abortion. In fact, he had very little to say on either topic. Contraception is discussed, along with masturbation, in a question in the Summa contra Gentiles concerning ‘the disordered emission of semen’. Aquinas maintains that this is a crime against humanity, second only to homicide. This claim rests on the belief that only the male provides the active element in conception, so that the sperm has an individual history continuous with the embryo, the fetus, and the infant. In fact, of course, male and female gametes contribute equally to the genetic constitution of the eventual human being. An embryo, unlike the father’s sperm or semen, is the same individual organism as an infant at birth. For Aquinas, the emission of semen in circumstances unsuitable for conception was the same kind of thing, on a minor scale of course, as the exposure or starvation of an individual infant. That is why he thought masturbation a poor man’s version of homicide."
Uta Ranke-Heinemann, in Eunuchs for the Kingdom of Heaven: Women, Sexuality, and the Catholic Church, notes:
"For Thomas, every sexual act has to be a marital act, and every marital act has to be an act of procreation. A violation of the sexual commandments is a violation of life itself. For the semen already contains the potential for the whole person (or, more precisely, the whole man, for women come into being only when something goes awry in the process of development; De malo 15 a. 2). The unregulated ejaculation runs counter to the well-being of nature, which lies in the preservation of the species. Therefore, after the sin of murder, through which human nature, which already exists in reality, is destroyed, the sin of preventing the generation of human nature comes in second place (Summa Contra Gentiles III, 122). Contraception is thus not the same thing as murder, but is very close to it. Along with Aristotle, Thomas calls semen 'something divine' (De malo 15, 2)."
Otto Weininger, in Sex and Character: An Investigation of Fundamental Principles, counters:
"[I]t cannot be a moral duty to ensure the continuation of the species, as is so frequently argued. This excuse is such an obviously barefaced lie that I hesitate to make a fool of myself by asking whether any human being has ever performed sexual intercourse with the thought of having to avert the great danger of the demise of humankind, […] and nobody who asks himself sincerely will feel it to be his duty to ensure the continuing existence of the human species. But what is not felt to be a duty is not a duty."
A holistic critique emphasizes viewing humans as psycho-physical unities, not isolated parts. Peter Vardy, in The Puzzle of Ethics, states:
"It may also be argued that Aquinas’ approach is not holistic – it fails to consider the human being as a psycho-physical unit. To separate, for instance, genitalia out as having a particular purpose on their own without considering the whole complexity of a person’s relationship to his or her body, psychology, sexuality in general, the ability of human beings as embodied persons to express and receive love and to come to their full humanity may be a diminution of human beings as people. We are not an accumulation of ‘bits’ – we are whole human persons and all moral judgements must take our complexity as human persons into account."
Melissa Moschella, in Old Natural Law Theory, Marriage, and Sexual Ethics, adds:
"Feser’s argument about sexual ethics makes the mistake of beginning with the ends of one bodily system (the reproductive system) and presuming them to be ends of the person as a whole."
Reconsidering Homosexuality within Natural Law
Even within Old Natural Law, homosexual acts need not be deemed immoral if viewed as natural, akin to animal behaviors, and healthy for practitioners. Otto Weininger observes:
"[I]t is still worth remarking that sexually inverted people can otherwise be perfectly healthy and, apart from accessorial social factors, do not feel worse than all the other healthy people. If one asks them whether they have any wish to be different in this respect, one quite often receives a negative answer."
Dirk Baltzly, in Peripatetic Perversions: A Neo-Aristotelian Account of the Nature of Sexual Perversion, questions:
"I think that perversions, if there are any such things, are either sexual manifestations of various aspects of bad moral character or states that are psychologically inextricable from bad moral character. I am myself unsure whether there are any sexual perversions. […], I am very confident that the psychological generalisations that have underwritten the claim that homosexuality is a perversion are false."
Alan Soble, in Philosophy of Sexuality, asserts:
"Whether a sexual activity is natural or perverted does not depend [...] on what organs are used or where they are put, but only on the character of the psychology of the sexual encounter."
Mel Thompson challenges:
"One might argue that the presence of sexual organs in a human being implies that he or she is designed for sexual activity and the conception of children – in which case, celibacy is as unnatural as homosexuality, since it is a denial of the complete natural function of procreation. If this is established, then it is illogical to accept a celibate partnership between those who are sexually attracted. Some people are naturally attracted by members of the same sex. They experience their feelings as completely natural. Any difficulties that arise are the result of social conditioning, not nature. Sexuality can be said to achieve three ends: 1. physical pleasure 2. the deepening of a relationship 3. the conception of children Only the third end is precluded by homosexual relationships. But is not the search for pleasure and for deep relationships as natural as the conception of children? If a marriage is known to be infertile, are heterosexual acts between its partners therefore immoral simply because conception is impossible Marriage is a social function, and promiscuity can be practised equally by homosexuals and heterosexuals. The fact that homosexual couples cannot marry does not preclude deep and permanent relationships. If a homosexual couple form a stable relationship, they may be able to offer children a home that is, at the very least, as valuable to their upbringing as one in which there is either a single parent, or a heterosexual couple with a bad relationship. Hence, it would seem illogical to discriminate in this matter. In pointing out some of the ways in which the ‘natural law’ view of the homosexual couple’s situation might be challenged, it is not intended to undermine the principle of natural law as such, but to show that there are some areas of morality – particularly where relationships are concerned – where it is difficult to consider morality mainly in terms of specific actions."
Kurt Blankschaen, in Rethinking Same-Sex Sex in Natural Law Theory, proposes:
"Many prominent proponents of Old and New Natural Law morally condemn sexual acts between people of the same sex because those acts are incapable of reproduction; they each offer a distinct set of supporting reasons. While some New Natural Law philosophers have begun to distance themselves from this moral condemnation, there are not many similarly ameliorative efforts within Old Natural Law. I argue for the bold conclusion that Old Natural Law philosophers can accept the basic premises of Old Natural Law without also being committed to morally condemning sexual activity between people of the same sex. I develop an argument from analogy that shows how we can draw metaphysically distinct subcategories based on someone’s capacity to experience the unitive goods of sex. This unitive capacity constitutes the sub-category and provides a distinct principle for evaluating how members of that sub-category (X) act as members of that sub-category, rather than as acting as defective members of another category (Y). Even though my argument is ‘internal’ to Old Natural Law, I conclude by showing how these conclusions can also address some of the objections to same-sex sex in New Natural Law."
Historical Development in Catholic Teaching on Contraception
Catholic doctrine on contraception has evolved, reflecting historicity without complete reversal. Katie Grimes, in Butler Interprets Aquinas: How to Speak Thomistically About Sex, notes:
"When Catholics embrace the essentially eschatological and therefore unfinished character of the process of natural law knowledge, they realize that the reliability of the tradition is neither destroyed nor diminished by its errors. In this way, the discovery of the humanity of homosexuality does not overturn the authority of the man who once condemned it. Heterosexual Catholics need no longer fear the ecclesial inclusion of lesbians and gays while lesbian and gay Catholics need no longer fear the Thomistic texts that have been so expertly used against them. Misrepresented as an author who underwrites magisterial terror, Aquinas reveals himself to be a source of lesbian and gay Catholic empowerment."
John T. Noonan, Jr., in Contraception: A History of Its Treatment by the Catholic Theologians and Canonists, summarizes:
"The recorded statements of Christian doctrine on contraception did not have to be read in a way requiring an absolute prohibition. The doctrine had been molded by the teaching of the Gospels on the sanctity of marriage; the Pauline condemnation of unnatural sexual behavior; the Old Testament emphasis on fertility; the desire to justify marriage while extolling virginity; the need to assign rational purpose and limit to sexual behavior. The doctrine was formed in a society where slavery, slave concubinage, and the inferiority of women were important elements of the environment affecting sexual relations. The education of children was neither universal nor expensive. Underpopulation was a main governmental concern. The doctrine condemning contraception was formulated against the Gnostics, reasserted against the Manichees, and established in canon law at the climax of the campaign against the Cathars. Reaction to these movements hostile to all procreation was not the sole reason for the doctrine, but the emphases, sweep, and place of the doctrine issued from these mortal combats. The environmental changes requiring a reconsideration of the rule accumulated only after 1850. These changes brought about a profound development of doctrine on marriage and marital intercourse: love became established as a meaning and end of the coital act. Before women were emancipated and marriages in the West came to be based on personal decision, writing like that of Von Hildebrand, Doms, Haring, Suenens, Fuchs, Ford, and Kelly would have seemed chimerical. Their work responded to the change in conditions. Their teaching on marriage was in many ways different from that of older theologians. Huguccio would have marveled at the teaching of Ford and Kelly, Jerome would have been astounded at Haring. Suppose the test of orthodoxy were, Would Augustine or Thomas be surprised if he were to return and see what Catholic theologians are teaching today? By this criterion, the entire development on the purposes of marital intercourse would have been unorthodox. But it is a perennial mistake to confuse repetition of old formulas with the living law of the Church. The Church, on its pilgrim's path, has grown in grace and wisdom. That intercourse must be only for a procreative purpose, that intercourse in menstruation is mortal sin, that intercourse in pregnancy is forbidden, that intercourse has a natural position - all these were once common opinions of the theologians and are so no more. Was the commitment to an absolute prohibition of contraception more conscious, more universal, more complete, than to these now obsolete rules? These opinions, now superseded, could be regarded as attempts to preserve basic values in the light of the biological data then available and in the context of the challenges then made to the Christian view of man. At the core of the existing commitment might be found values other than the absolute, sacral value of coitus. Through a variety of formulas, five propositions had been asserted by the Church. Procreation is good. Procreation of offspring reaches its completion only in their education. Innocent life is sacred. The personal dignity of a spouse is to be respected. Marital love is holy. In these propositions the values of procreation, education, life, personality, and love were set forth. About these values a wall had been built; the wall could be removed when it became a prison rather than a bulwark."
Thompson adds:
"Sex within the ‘safe period’ of the woman’s ovulatory cycle is generally permitted in Catholic moral teaching because the failure to conceive at that time is part of nature’s limitation, rather than the result of a direct attempt to do something unnatural."
Noonan elaborates:
"At the most on four days a month is the union of intercourse and fertility normal. If we seek to understand the divine plan from what nature has given humanity, we must infer that it is for a brief part of any life that fertility is intended, and that nature has designed man so that many acts of intercourse will be sterile. […] The reason a sterilizing act is wrong is that it asserts man's dominion over the generative process and effects the disruption of the natural nexus. But when steps are taken to assure that intercourse is not fertile in a period not intended by nature to be fertile, man acts in subordination to the divine plan and does not effect any disruption of the sacred link between love and fertility. Further, the directly intended act is the assurance of natural sterility. [...] But at those times when nature intends no procreation, there is no interference in the structure or signification of the sexual act when means are used increasing the probability that the natural rhythm will hold."
David Bradshaw, in What Does it Mean to be Contrary to Nature?, notes:
"Perhaps most interestingly, a physician who played a leading role in the development of the Pill, John Rock, argued vigorously that the Pill fit comfortably within existing Catholic teaching. He reasoned that since it uses a naturally occurring hormone, progesterone, to extend a woman's infertile period, it is effectively no more than an aid to the rhythm method."
Conclusion
These critiques underscore that Thomistic natural law falters as a standalone philosophical framework, relying instead on unbridgeable logical gaps and ecclesiastical authority for its normative force. The adaptability of Catholic teaching on contraception illustrates natural law's non-static nature, highlighting its responsiveness to new insights and societal changes.
