Home » Homosexuality and the “Unnaturalness Argument”

Homosexuality and the “Unnaturalness Argument”

by Burton M. Leiser (From Usenet’s public gay forum)

[The alleged “unnaturalness” of homosexuality] raises the question of the meaning of nature, natural, and similar terms. Theologians and other moralists have said that [homosexual acts] violate the “natural law,” and that they are therefore immoral and ought to be prohibited by the state.

The word “nature” has a built-in ambiguity that can lead to serious misunderstandings. When something is said to be “natural” or in conformity with “natural law” or the “law of nature,” this may mean either (1) that it is in conformity with the descriptive laws of nature, or (2) that it is not artificial, that man has not imposed his will or his devices upon events or conditions as they exist or would have existed without such interference.


The laws of nature, as these are understood by the scientist, differ from the laws of man. The former are purely descriptive, whereas the latter are prescriptive. When a scientist says that water boils at 212 Fahrenheit or that the volume of a gas varies directly with the heat that is applied to it and inversely with the pressure, he means merely that as a matter of recorded and observable fact, pure water under standard conditions always boils at precisely 212 Fahrenheit and that as a matter of observed fact, the volume of a gas rises as it is heated and falls as pressure is applied to it. These “laws” merely describe the manner in which physical substances actually behave.

They differ from municipal and federal laws in that they do not prescribe behaviour. Unlike manmade laws, natural laws are not passed by any legislator or group of legislators; they are not proclaimed or announced; they impose no obligation upon anyone or anything; their “violation” entails no penalty, and there is no reward for “following” them or “abiding by” them. When a scientist says that the air in a tire “obeys” the laws of nature that “govern” gases, he does not mean that the air, having been informed that it ought to behave in a certain way, behaves appropriately under the right conditions. He means, rather, that as a matter of fact, the air in a tire will behave like all other gases.

In saying that Boyle’s law “governs” the behaviour of gases, he means merely that gases do, as a matter of fact, behave in accordance with Boyle’s law, and that Boyle’s law enables one to predict accurately what will happen to a given quantity of gas as its pressure is raised; he does not mean to suggest that some heavenly voice has proclaimed that all gases should henceforth behave in accordance with the terms of Boyle’s law and that a ghostly policeman patrols the world, ready to mete out punishments to any gases that “violate” the heavenly decree.

In fact, according to the scientist, it does not make sense to speak of a natural law being violated. For if there were a true exception to a so-called law of nature, the exception would require a change in the description of those phenomena, and the “law” would have been shown to be no law at all. The laws of nature are revised as scientists discover new phenomena that require new refinements in their descriptions of the way things actually happen. In this respect, they differ fundamentally from human laws, which are revised periodically by legislators who are not so interested in describing human behaviour as they are in prescribing what human behaviour should be.


On occasion when we say that something is not natural, we mean that it is a product of human artifice. My typewriter is not a natural object, in this sense, for the substances of which it is composed have been removed from their natural state – the state in which they existed before men came along – and have been transformed by a series of chemical and physical and mechanical processes into other substances. They have been rearranged into a whole that is quite different from anything found in nature. In short, my typewriter is an artificial object.

In this sense, the clothing that I wear as I lecture before my students is also not natural, for it has been transformed considerably from the state in which it was found in nature; and my wearing of clothing as I lecture before my students is also not natural, in this sense, for in my natural state, before the application of anything artificial, before any human interference with things as they are, I am quite naked. Human laws, being artificial conventions designed to exercise a degree of control over the natural inclinations and propensities of men, may in this sense be considered to be unnatural.

Now when theologians and moralists speak of homosexuality, contraception, abortion, and other forms of human behaviour as being unnatural, and say that for that reason such behaviour must be considered to be wrong, in what sense are they using the word unnatural? Are they saying that homosexual behaviour and the use of contraceptives are contrary to the scientific laws of nature, are they saying that they are artificial forms of behaviour, or are they using the terms natural and unnatural in some third sense?

They cannot mean that homosexual behaviour (to stick to the subject presently under discussion) violates the laws of nature in the first sense, for, as we have pointed out, in that sense it is impossible to violate the laws of nature. Those laws, being merely descriptive of what actually does happen, would have to include homosexual behaviour if such behaviour does actually take place. Even if the defenders of the theological view that homosexuality is unnatural were to appeal to a statistical analysis by pointing out that such behaviour is not normal from a statistical point of view, and therefore not what the laws of nature require, it would be open to their critics to reply that any descriptive law of nature must account for and incorporate all statistical deviations, and that the laws of nature, in this sense, do not require anything.

These critics might also note that the best statistics available reveal that about half of all American males engage in homosexual activity at some time in their lives, and that a very large percentage of American males have exclusively homosexual relations for a fairly extensive period of time; from which it would follow that such behaviour is natural, for them, at any rate, in this sense of the word natural.

If those who say that homosexual behaviour is unnatural are using the term unnatural in the second sense, it is difficult to see why they should be fussing over it. Certainly nothing is intrinsically wrong with going against nature (if that is how it should be put) in this sense. That which is artificial is often far better than what is natural. Artificial homes seem, at any rate, to be more suited to human habitation and more conducive to longer life and better health than caves and other natural shelters. There are distinct advantages to the use of such unnatural (i.e. artificial) amenities as clothes, furniture, and books.

Although we may dream of an idyllic return to nature in our more wistful moments, we would soon discover, as Thoreau did in his attempt to escape from the artificiality of civilisation, that needles and thread, knives and matches, ploughs and nails, and countless other products of human artifice are essential to human life. We would discover, as Plato pointed out in the Republic, that no man can be truly self-sufficient. Some of the by-products of industry are less than desirable; but neither industry itself, nor the products of industry, are intrinsically evil, even though both are unnatural in this sense of the word.

Interference with nature is not evil in itself. Nature, as some writers have put it, must be tamed. In some respects man must look upon it as an enemy to be conquered. If nature were left to its own devices, without the intervention of human artifice, men would be consumed with disease, they would be plagued by insects, they would be chained to the places where they were born with no means of swift communication or transport, and they would suffer the discomforts and the torments of wind and weather and flood and fire with no practical means of combating any of them. Interfering with nature, doing battle with nature, using human will and reason and skill to thwart what might otherwise follow from the conditions that prevail in the world, is a peculiarly human enterprise, one that can hardly be condemned merely because it does what is not natural.


Homosexual behaviour can hardly be considered to be unnatural in this sense. There is nothing “artificial” about such behaviour. On the contrary, it is quite natural, in this sense, to those who engage in it. And even if it were not, even if it were quite artificial, this is not in itself a ground for condemning it.

It would seem then, that those who condemn homosexuality as an unnatural form of behaviour must mean something else by the word unnatural, something not covered by either of the preceding definitions. A third possibility is this:


If this is what is meant by those who condemn homosexuality on the ground that it is unnatural, it is quite obvious that their condemnation cannot be accepted without further argument, for the fact that a given form of behaviour is uncommon provides no justification for condemning it. Playing viola in a string quartet is no doubt an uncommon form of human behaviour. I do not know what percentage of the human race engages in such behaviour, or what percentage of his life any given violist devotes to such behaviour, but I suspect that the number of such people must be very small indeed, and that the total number of man-hours spent in such activity would justify our calling that form of activity uncommon, abnormal (in the sense that it is statistically not the kind of thing that people are ordinarily inclined to do), and therefore unnatural, in this sense of the word.

Yet there is no reason to suppose that such uncommon, abnormal behaviour is, by virtue of its uncommonness, deserving of condemnation or ethically or morally wrong. On the contrary, many forms of behaviour are praised precisely because they are so uncommon. Great artists, poets, musicians, and scientists are “abnormal” in this sense; but clearly the world is better off for having them, and it would be absurd to condemn them or their activities for their failure to be common and normal. If homosexual behaviour is wrong, then, it must be for some reason other than its “unnaturalness” in this sense of the word.


Every organ and every instrument-perhaps even every creature-has a function to perform, so some people argue, one for which it is particularly designed.

Any use of those instruments and organs that is consonant with their purposes is natural and proper, but any use that is inconsistent with their principal functions is unnatural and improper, and are to that extent, evil or harmful.

Human teeth, they give as example, are admirably designed for their principal functions-biting and chewing the kinds of food suitable for human consumption. But they are not particularly well suited for prising the caps from beer bottles. If they are used for the latter purpose, which is not natural to them, they are

liable to crack or break under the strain. The abuse of one’s teeth leads to their destruction and to a consequent deterioration in one’s overall health. If they are used only for their proper function, however, they may continue to serve well for many years.

Similarly, they offer, a given drug may have a proper function. If used in the furtherance of that end, it can preserve life and restore health. But if it is abused, and employed for purposes for which it was never intended, it may cause serious harm and even death. The natural uses of things are good and proper, but their unnatural uses are bad and harmful.

What we must do, then, is to find the proper use, or the true purpose, of each organ in our bodies. Once we have discovered that, we will know what constitutes the natural use of each organ, and what constitutes an unnatural, abusive, and potentially harmful employment of the various parts of our bodies. If we are rational, we will be careful to confine our behaviour to our proper functions and to refrain from unnatural behaviour. According to those philosophers who follow this line of reasoning, the way to discover the “proper” use of any organ is to determine what it is peculiarly well suited to do. The eye is suited for seeing, the ear for hearing, the nerves for transmitting impulses from one part of the body to another, and so on.

What are the sex organs peculiarly suited to do? Obviously, they are peculiarly suited to enable men and women to reproduce their own kind. No other organ in the body is capable of fulfilling that function. It follows, according to those who follow the natural-law line, that the “proper” or “natural” function of the sex organs is reproduction, and that strictly speaking, any use of those organs for other purposes is unnatural, abusive, potentially harmful, and therefore wrong. The sex organs have been given to use in order to enable us to maintain the continued existence of mankind on this earth. All perversions – including masturbation, homosexual behaviour, and heterosexual intercourse that deliberately frustrates the design of the sexual organs – are unnatural and bad. As Pope Pius XI once said, “Private individuals have no other power over the members of their bodies than that which pertains to their natural ends.”

But the problem is not so easily resolved. Is it true that every organ has one and only one proper function? 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. A woman’s eyes are well adapted to seeing, it is true. But they seem also to be well adapted to flirting. Is a woman’s use of her eyes for the latter purpose sinful merely because she is not using them, at that moment, for their “primary” purpose of seeing?


Our sexual organs are uniquely adapted for procreation, but that is obviously not the only function for which they are adapted. Human beings may – and do ­use those organs for a great many other purposes, and it is difficult to see why anyone use should be considered to be the only proper one. The sex organs, for one thing, seem to be particularly well adapted to give their owners and others intense sensations of pleasure. Unless one believes that pleasure itself is bad, there seems to be little reason to believe that the use of the sex organs for the production of pleasure in oneself or in others is evil. In view of the peculiar design of these organs, with their great concentration of nerve endings, it would seem that they were designed (if they were designed) with that very goal in mind, and that their use for such purposes would be no more unnatural than their use for the purpose of procreation.

Nor should we overlook the fact that human sex organs may be and are used to express, in the deepest and most intimate way open to man, the love of one person for another. Even the most ardent opponents of “unfruitful” intercourse admit that sex does serve this function. They have accordingly conceded that a man and his wife may have intercourse even though she is pregnant, or past the age of child bearing, or in the infertile period of her menstrual cycle.

Human beings are remarkably complex and adaptable creatures. Neither they nor their organs can properly be compared to hammers or to other tools. The analogy quickly breaks down. The generalisation that a given organ or instrument has one and only one proper function does not hold up, even with regard to the simplest manufactured tools, for, as we have seen, a tool may be used for more than one purpose-less effectively than one especially designed for a given task, perhaps, but “properly” and certainly not sinfully. A woman may use her eyes not only to see and to flirt, but also to earn money – if she is, for example, an actress or a model. Though neither of the latter functions seems to have been a part of the original “design,” if one may speak sensibly of design in this context, of the eye, it is difficult to see why such a use of the eyes of a woman should be considered sinful, perverse, or unnatural.

Her sex organs have the unique capacity of producing ova and nurturing human embryos, under the right conditions; but why should any other use of those organs, including their use to bring pleasure to their owner or to someone else, or to manifest love to another person, or even, perhaps, to earn money, be regarded as perverse, sinful, or unnatural? Similarly a man’s sexual organs possess the unique capacity of causing the generation of another human being, but if a man chooses to use them for pleasure, or for the expression of love, or for some other purpose – so long as he does not interfere with the rights of some other person – the fact that his sex organs do have their unique capabilities does not constitute a convincing justification for condemning their other uses as being perverse, sinful, unnatural, or criminal.


If a man “perverts” himself by wiggling his ears for the entertainment of his neighbours instead of using them exclusively for their “natural” function of hearing, no one thinks of consigning him to prison. If he abuses his teeth by using them to pull staples from memos–a function for which teeth were clearly not designed – he is not accused of being immoral, degraded, and degenerate. The fact that people are condemned for using their sex organs for their own pleasure or profit, or for that of others, may be more revealing about the prejudices and taboos of our society than it is about our perception of the true nature or purpose or “end” (whatever that might be) of our bodies.

To sum up, then, the proposition that any use of an organ that is contrary to its principal purpose or function is unnatural assumes that organs have a principal purpose or function, but this may be denied on the ground that the purpose or function of a given organ may vary according to the needs or desires of its owner. It may be denied on the ground that a given organ may have more than one principal purpose or function, and any attempt to call one use or another the only natural one seems to be arbitrary, if not question-begging. Also, the proposition suggests that what is unnatural is evil or depraved. This goes beyond the pure description of things, and enters into the problem of the evaluation of human behaviour, which leads us to the fifth meaning of “natural.”


When one condemns homosexuality or masturbation or the use of contraceptives on the ground that it is unnatural, one implies that whatever is unnatural is bad, wrongful, or perverse. But as we have seen, in some sense of the word, the unnatural (i.e., the artificial) is often very good, whereas that which is natural (i.e., that which has not been subjected to human artifice or improvement) may be very bad indeed.

Of course interference with nature may be bad. Ecologists have made us more aware than we have ever been of the dangers of unplanned and uninformed interference with nature. But this is not to say that all interference with nature is bad. Every time a man cuts down a tree to make room for a home for himself, or catches a fish to feed himself or his family, he is interfering with nature. If men did not interfere with nature, they would have no homes, they could eat no fish, and, in fact, they could not survive. What, then, can be meant by those who say that whatever is natural is good and whatever is unnatural is bad?

Clearly, they cannot have intended merely to reduce the word natural to a synonym of good, right, and proper, and unnatural to a synonym of evil, wrong, improper, corrupt and depraved. If that were all they had intended to do, there would be very little to discuss as to whether a given form of behaviour might be proper even though it is not in strict conformity with someone’s views of what is natural; for good and natural, being synonyms, it would follow inevitably that whatever is good must be natural and vice versa, by definition.

This is certainly not what the opponents of homosexuality have been saying when they claim that homosexuality, being unnatural, is evil. For if it were, their claim would be quite empty. They would be saying merely that homosexuality, being evil, is evil – a redundancy that could as easily be reduced to the simpler assertion that homosexuality is evil. This assertion, however, is not an argument. Those who hold that homosexuality and other sexual “perversions” are “evil” on the ground that they are “unnatural” are saying that there is some objectively identifiable quality in such behaviour that is unnatural; and that that quality, once it has been identified by some kind of scientific observation, can be seen to be detrimental to those who engage in such behaviour, or to those around them; and that because of the harm (physical, mental, moral, or spiritual) that results from engaging in any behaviour possessing the attribute of unnaturalness, such behaviour must be considered to be wrongful, and should be discouraged by society.

“Unnaturalness” and “wrongness” are not synonyms, then, but different concepts. The problem with which we are wrestling is that we are unable to find a meaning for unnatural that enables us to arrive at the conclusion that homosexuality is unnatural or that if homosexuality is unnatural, it is therefore wrongful behaviour. We have examined four common meanings of natural and unnatural, and have seen that none of them performs the task that it must perform if the advocates of this argument are to prevail. Without some more satisfactory explanation of the connection between the wrongfulness of homosexuality and its alleged unnaturalness, the argument must be rejected.