A Reading of Nagel on Sexual Perversion

Article Preface:

As you no doubt gathered from the title of this article, this article will be about sex. The main focus of the essay and therefore article is about paraphilias, which is sort of synonymous with “sexual deviancy.” In other words, the article will make mention—it will not delve into, only make mention—of sex with animals and sex with children. There will be mentions of masochism, sadism, and rape.

1. If these are subjects that disturb you, either because they are gross, profane, or taboo, or because you are offended at their discussion in the first place, do not proceed.

2. If you do not wish to acquire the intricate details (not really that much) of the present Author’s sexual experiences, then do not proceed.

3. I should mention that this article is nothing really beyond a personal response to Nagel’s essay. In performing this written review, I myself can come to a better understanding of what Nagel is talking about. It also allows me to formulate my own thoughts on the subject, and that is a large part of what you will read below.

4. The book we are reading is Philosophy & Sex by Robert Baker and Frederick Elliston. You’ll only see me refer to it a few times (I forgot how many) in the essay before I just abbreviate it as PAS, or completely drop it from the reference pages.

A Reading of Nagel on Sexual Deviancy

An Overview, and First Thoughts

It was interesting to discover that the mind-body philosopher so famous for his [What Is It Like to Be a Bat?](https://en.wikipedia.org/wiki/What_Is_It_Like_to_Be_a_Bat%3F) had ventured into the realm of sexual experience—specifically the subdomain of sexual perversion. (What exactly is that? I guess we’ll find out shortly.) I didn’t expect it. For example, the Wikipedia article for Thomas Nagel (as it stands at the time of this writing) has mention after mention of his work in the philosophy of mind; it is only after doing a dedicated Ctrl + F search for the keyword “sex” that one finds his 1969 essay Sexual Perversion .

Of course, as I believe, the question and analysis of sexuality, and specifically that of paraphilias, has the utmost sensitivity to the tanglings of the outstanding mind-body debacle. With contemporary scientific literature probing the variety of related phenomena, such as the physiology and neurology of orgasms, the genetic, psychological, and social bases for sexual orientation, and the psychology, neuroscience, and anthropology of the whole mess of attraction, desire, love, and sexual intercourse, the tension surrounding a resolution to these questions continues to increase—not to make any sort of allusion, of course. Nevertheless, despite so much attention converging from so many angles to this domain of human activity, concrete answers continue to elude us. And in a social climate in which various sub-behaviors of human sexual expression are repressed, we may not be able to conduct the research and analysis necessary to provide a thoughtful explanation for this aspect of our lives—it is difficult enough to recruit individuals to participate in a study on, say, how one experiences masturbation.

Thomas Nagel in the essay proposes a “psychological account of sexual perversion” (p. 248 in Philosophy & Sex). Therein, he outlines a heuristic model for how sexual perversion and deviance may arise. I find the psychoanalytic model compelling. It’s interesting, to say the least. On the other hand, he does not offer much empirical evidence from the fields of “hard science” such as neurobiology, the field of which itself is composed of multiple other disciplines such as cellular biology, neuroscience, immunology, endocrinology, psychology, and the list goes on. And, of course, human sex is between humans, and one must do well to keep in mind that the social components of this interpersonal behavior are just as important as, if not more important than, the lower-level biological components. Take, for example, the male orgasm: It is well understood at the anatomical and biological level; it has only been relatively recently discovered that perhaps more than half of the “stuff of orgasm” in fact takes place in the brain. That is, we can mechanistically outline in detail the peristalsis of the pelvic muscles and the mixture of the sperm with semen to produce the ejaculate which is forced out of the penile urethral opening. But certainly (most) men are not having orgasms on the daily commute to work, at the gym, or when making breakfast; that orgasms are highly correlated with a particular kind of social context makes it enormously difficult to even suggest a decoupling of biology, psychology, and sociology. Consider that there are phenomenological accounts (case studies) of people (biological women) thinking themselves to the point of orgasm. In other words, no physical stimulation was required to achieve an orgasm of equal intensity.

As I have stressed many times before—though I find myself with each time not exasperated but rather enthralled—it is precisely within this realm of human experience, namely sexual activity and its broad scope, that the largest collision of scientific and cultural commentary on the subject occurs. And yet we find ourselves not well-equipped in the slightest to make claims about the inner workings of our sexual identities. To further complicate the mission, the most dramatic of all challenges in this realm is the understanding of paraphilias, or sexual deviancy. I claim that the existence of paraphilias throws yet another wrench into any contemporary approach at understanding sexual orientation, sexual behavior, and thereby back-includes human psychology and behavior.

To think that all of these dimensions and aspects of human experience are at play whenever we lay down to have sex is so inconceivable that they often go completely unnoticed—at least until after orgasm, and we are all familiar with the notion of “pillow talk.” And of course it should: we’re having sex! That’s fun, as the main premise of the book entitled book:[This Is Supposed to Be Fun] reminds us. But does it not give you pause to consider the dissonance: In the heat of the moment, we are so enveloped in the passion of sex that all of the elements that enabled its practice go unnoticed. That the social dynamics of attraction and love and sex provoke such potent biological desire and behavior, all of course embedded in our vast, interconnected central nervous system, have wound us up here, feeling each other’s body—or, in the case of paraphilia, perhaps just feeling a shoe.

Nevertheless, the essay was a pleasure to read and learn from! Many other essays in the collection Philosophy & Sex have read as verbose and constipating, but it is a pleasure to read Nagel. In fact, it appears that he himself is aware of how poetically abstruse past philosophers can be, as he provides a quotation from Jean Paul Sartre, after which he remarks, “The view I am going to suggest—I hope in less obscure language—is related to Sartre’s…” (p. 252 in PAS). Not only that, but he has fluency in the way of analogy, as those who have read What Is It Like to Be a Bat? certainly are acquainted with. In the present essay, he analogizes sexual desire to a human appetite, with specific emphasis on so-called gastronomical appetite (i.e. eating food).

In addition to his analogies, he provided a grounding physical scenario as an example of how his psychoanalytic model might manifest in the real world. This “room of mirrors” scene was wonderful, if not slightly complicated near the end (“unobserved observation and even mutual unobserved observation” (p. 253 in PAS)). Admittedly, I found myself feeling a little hot and bothered during that scene, though the scene was not particularly fleshed out in a narrative sense or descriptive sense. (And what’s reading about the philosophy of sex without a little fan service, right?) For me, it is certainly the notion that you can observe someone by not looking directly at them as aided by a labyrinth of mirrors. I have these kinds of thoughts every so often when I go to the gym and accidentally catch myself gazing in a direction that happens to empty out onto an unsuspecting individual (“unobserved observation”). I also have them on the bus when I realize that I am not just looking out the window but also seeing the reflection of another passenger sitting farther up the aisle. Just consider the passage itself: “But now, cleverly calculating the line of her stare without actually looking her in the eyes, he realizes that [her stare] is directed at him through the mirror on the opposite wall” (p. 253 in PAS). Yes, indeed: in the game of eye contact, one cannot abdicate the importance of strategy and calculation: who is looking at whom at what time and when? And how can I catch a glimpse without being caught?

What is sexual perversion?

As per usual, Nagel’s excellent writing does not leave anything up to the imagination. In a subject as entangled as sexual experience, let alone something on the periphery of the experience, clarity of prose is in high demand. So, we do not have to guess what Nagel believes the origin of perversion is: “I believe that various familiar deviations constitute truncated or incomplete versions of the complete configuration and may therefore be regarded as perversions of the central impulse” (p. 256). The “central impulse” here refers to the recursive, meta-cognitive dynamic that he spends the essay outlining. It spontaneously reminds me of the TCP handshake between a client and a server: The client sends the server SYN, the server sends back SYN ACK, and then the client establishes the ACK, and starts transferring data: If the server you are connecting to does not send you the SYN ACK, you cannot begin to transfer data. That is, you must be aware that the other person is aroused due to your arousal due to them! “I am turned on by you,” you wish to say out loud, but you can sense that they have already acknowledged your feeling this—and they themselves have become aroused because of that.

Now, equipped with this model, we can all think of things that may reign as sexually deviant: attraction to infants, animals, and sadomasochism. Nagel’s theory enables us to determine if indeed these traditional paraphilias can be understood to be such.

Let us take, for example, sexual attraction to an object that is not animate—understanding this example is essential for approaching an understanding of fetishes because, according to a paragraph on the Wikipedia article for sexual fetishism, “Originally, most medical sources defined fetishism as a sexual interest in non-living objects, body parts or secretions.” Since, Nagel says, the object that is not animate cannot partake in any social dynamic of mutual sexual excitement, then “…the experience is reduced entirely to an awareness of one’s own sexual embodiment” (p. 256). So, that there is no reciprocity between the sexual participant and the inanimate object, we can classify this behavior as a paraphilia.

He covers sexual attraction to animals and small children in the same breath: “Small children and animals permit awareness of the embodiment of the other, but present obstacles to reciprocity, to the recognition by the sexual object of the subject’s desire as the source of his (the object’s) sexual self-awareness” (p. 256). (The words “animals and small children” are of course and without a doubt referring to animals and human children, but note that the language used did not disambiguate!) It is interesting that Nagel considers animals and human children in the same breath, because there is a major difference between them: human children become human adults. If the “reciprocity” that Nagel referring to here is more easily achievable between adult humans, then Nagel silently prescribes a developmental detail here: children, unlike animals, can transition from an inability to participate in social reciprocation to an ability to do so. In other words, children who grow up somehow learn along the way to recognize that their sexual desire is sourced by seeing the sexual desire for them in someone else. (If everything goes well, of course.) But the point here is that he does not differentiate between children animals and adult animals—he simply treats both all animals and small children in one breath: “small children and animals.” Since animals “present obstacles to recipocity,” he does not prescribe any developmental details for how animals may acquire a meta-cognitive awarness of their sexual embodiment; rather, they just do. So, (adult) humans sexually attracted to animals should find themselves never receiving SYN ACK.

Nagel’s explanation of sadistic behavior was a little weak to me. Nagel essentially claims that a sadist is so overwhelmed in the sexual pursuit that he cannot uncover the required awareness that he is also a participant in the mutual sexual exchange: “…the sadist’s engagement is itself active and requires a retention of deliberate control that impedes awareness of himself as a bodily subject of passion in the required sense” (p. 256). It reads weak to me because he added several new ingredients to the sexual interplay that are not explored in the same essay: self-control, exertion of power, deliberacy, and so on. This issue is precisely the one that I commented on in the introduction: In order to holistically understand these issues of sexuality, and especially sexual perversion, one must delve deeply into, for example, virtually all the issues of the human psyche. Of course, in a generous manner, one can read Nagel’s essay and acquire the gist of it easily—but only if they’re willing to accept the oh-so-evident universality of human experience.

Nagel’s explanation of masochism is also slightly confusing to me. The idea behind masochism as classifying as a sexual deviation is that the attention of the masochist is not directed in the fashion that enables the required reciprocity for sexual “success”; their attention is self-directed, as they objectify only themselves, failing again to reach across the aisle to acknowledge mutual sexual interest. But, like the commentary on sadism, Nagel throws out another complicated dynamic for us to consider, namely that of pain. He has not provided a “psychology of pain” that enables us to understand precisely how it interacts with sexual excitement. But I did find a fascinating phrase in the section on masochism: “pain causes people to contract rather than dissolve” (p. 257). In other words, to participate in the meta-cognitive handshake inexorably invites us to “dissolve [into] another,” that the boundaries between you and your sexual partner momentarily turn from solid lines to dashed lines. (It’s quite romantic, actually. I love it!)

Now, one of the corollaries of Nagel’s model is actually that sexual perversion in polygamous or open relationship-type interactions is… complicated! His crystal clear writing enables us to see immediately that these kinds of multiple-partner sexual interactions are only as “successful” as its participants can process the multi-layered meta-cognitive aspects of their interaction. “If one considers how difficult it is to carry on two conversations simultaneously, one may appreciate the problems of multiple simultaneous interpersonal perception that can arise in even a small-scale orgy. It may be inevitable that some of the component relations should degenerate into mutual epidermal stimulation by participants otherwise isolated from each other” (p. 257). Remember: The model would prescribe that maintaining the structure of mutual awareness increases in difficulty as the number of participants increases. (There have also been recent murmurs about the human’s fundamental inability to multitask, the most recent excitation of this probably manifesting in David Epstein’s new book :[Inside the Box: How Constraints Make Us Better]. Are we to dangerously associate the inability to conduct two simultaneous conversations as a notion of “multitasking?”) The addition of a third person to a pair of sexual partners requires adding another meta-cognitive ball to juggle. To what extent does this third participant become merely another object to the other two, to be the giver of epidermal stimulation?

One of the major implications that seems to follow from Nagel’s theory is that many kinds of sexual activities are not actually sexual deviations in the slightest despite their seemingly-evident appearance; as long as the “multilevel interpersonal awareness” is established, then “a liberal platitude about sex is upheld” (p. 257). What are some taboo sexual activities that make us shirk in disgust that must now find their liberation from (potentially discriminatory) classification as deviant? Oral intercourse is not generally perversion; anal intercourse is not generally perversion; and, crucially, from a historical perspective, homosexuality is not sexual deviancy.

Let’s now comment on homosexuality. Nagel’s theory enables us to clearly determine that same-sex sexual orientation does not fall under sexual perversion! He most certainly recognizes this: “…some version of the full range of interpersonal perceptions seems perfectly possible between two persons of the same sex” (p. 258). He acknowledges in his essay that homosexual sexual activity has different “mechanics” than heterosexual activity, and at the outset it seems to pose a challenge in identifying the so-called “sexual roles” of the two sexual partners. However: “one relevant observation is that a good deal of deviation from these roles occurs in heterosexual intercourse” (p. 258) as well. For example, a woman “pegging” a man (anally penetrating a man using a strap-on dildo) is one route to flip the “sexual roles” of heterosexual sex. Does it sound “perverted,” in the sense of revolting or taboo? Nagel’s theory does not classify it as such, but retains that the sexual relationship still be heterosexual. In other words, the account gives us no structural reason to categorize homosexual desire as perverse merely because the participants are of the same sex.

(Why is this point important to belabor? Because a common “criticism” of homosexual behavior is that it is “not right.” In the sense that I often hear, “right” is used to classify the behavior is deviant, perverted, dangerous, gross, or perhaps even suggest a product of mental illness. Now, if a behavior is classified as “not right,” it can frequently find itself disfavored or even criminalized by law. Is premeditated murder of another human “right” or “not right?” Is it legal or illegal in the United States?

If I may add one more thought to the one above, consider now that we have, more than ever, entertained the possibility of conducting sexual activity with AI-technology. The primitive example of this activity is perhaps the infamous blow-up doll… would Nagel describe sexual behavior between a human and a blow-up doll as sexual perversion? Now skip to the consideration of a human and a large-language model sexting? Hopefully, here we remind ourselves of why philosophy is quite important to engage in rather than abdicate the haste so encouraged by contemporary living standards. We now can understand why the philosophy of sex, especially, remains extremely relevant despite its incredibly sparse coverage.)

So, what is fascinating to me is that his theory requires us to abandon the suggestive, synonymous association of “perversion” with “gross,” and invite us to examine sexual perversion at the psychological level, the level that is often effectively incorporeal to our everyday experience. Sexual expression, then, is much more founded in what constitutes a person’s internal psychological dispositions rather than their external, outward character. It is difficult to believe that one’s sexual interests simply cannot be inferred based on any outward data, especially because there are now cultural identifiers for LGBT+ individuals. Ultimately, though, sexual deviancy is almost independent of the type of sexual behavior that sexual partners engage in; what is ultimate is their intact, meta-cognitive handshake. Is it possible, and will it ever be possible, for spectators of a sexual activity between consenting sexual partners to aptly characterize (or merely describe) what type of sexual activity is occurring?

There is one final implication that I wish to comment on: Rape clearly is classified as sexual deviancy. The victim of rape does not willingly participate in any kind of reciprocity. And here we find ourselves with another conundrum: Is sadism the same as rape? Nagel was quick to classify sadism as sexually deviant, so that perhaps the notion that we are so confident is already bad is promptly returned to its cave whence it came. However, there may be carefully-constructed social contexts in which the sadist’s desire in fact acts as the source of arousal for their sexual partner; no doubt would the sadist recognize this arousal in their partner and become more aroused. After all, many people have a rape fantasy. This observation must be acknowledged while simultaneously condemning rape. If, say, two sexual partners agree to stage a rape scene—“scene” here standing in contrast to non-consensual rape—it still would not be classified as sexual deviancy under Nagel’s theory.

Now, I mention rape only because I believe that there still exists a notion in our culture that those with sexual fetishes are aberrant, in the sense of revolting, abnormal, or, at worst, mentally ill. The most common type of sexual fetish that I hear circulate in popular culture is the “foot fetish.” Known clinically as “podophilia,” it has become a popular joke to incriminate somebody of having podophilia because it’s sort of embarrassing: Haha! You’re attracted to feet?! (In fact, I have been a victim of this joke about ten thousand times now.) However, the sexual arousal induced by the sight of feet cannot easily escape its primordial source: the foot belongs to another person. In that regard, if one of two sexual partners finds sexual allure with their partner’s feet, would Nagel’s theory classify this sexual interaction as deviancy? For the “owner” of the foot is aware that it is still their body that is the source of arousal for their partner. But the remaining question is the following: Does the foot-owner begin to feel aroused because of that awareness? If the foot-owner is repulsed by this observation, only then (in Nagel’s theory) is the behavior sexually deviant. Ultimately, what I wish to convey, then, by bringing up rape, is that foot fetishism is actually “safe” from classification of sexual deviancy while rape is further condemned to it.

Janitorial Duties

Now, I have mentioned to many of my friends before that I often feel like the “janitor” of argumentation. That is, once a sound argument is made, which is typically done within a particular context, I attempt to apply the argument to novel contexts to determine what else may be concluded. I have practiced this kind of lateral thinking frequently within physics, but it is actually harder to do because the basis of reasoning in physics is fundamentally mathematical; philosophy, though, which is frequently conducted using informal language upon an assumed analytical structure of logic, allows one to more readily insert novel words and phrases into the structure of the argumentation.

Here, we wish to apply Nagel’s model to contexts outside of sexual or pre-sexual interactions. Let me simply advance the likely possibility that virtually any social interaction between two or more people involves this kind of meta-cognition. For example, what makes me happy in a conversation—about nothing necessarily sexual—with a friend of mine? One thing that makes me happy is to see my friend! That’s the first step. The second step is to assess their reaction to seeing me. In fact, if my friend does not appear to be happy to see me, then I instinctively begin wondering what has gone wrong. I might think, Have I done something wrong? If not this question, I will still be plagued by other questions, some about our interpersonal relationship status: Are we still friends? I might nervously wonder.

In fact, this way of processing during interpersonal communication, this back-reactive, higher-order cognitive ping-pong, is a theme in the science of human communication—Charles Duhigg calls it the “matching principle.” Specifically, what makes a human conversation ebb and flow is the matching of each other’s valence and arousal (not sexual arousal—“arousal” is a scientific term here). So, of course, there must be some immediate assessment of your conversant’s reaction to your presence.

Indeed, Nagel does mention that this dynamic is typically at play in human interaction: “The general schema is important, however, and the proliferation of levels of mutual awareness it involves is an example of a type of complexity that typifies human interactions” (p. 254). Nagel then immediately provides an example related to aggression, but I actually found this example to fall flat. He continues, “If I am angry with someone, I want to make him feel it, either to produce self-reproach by getting him to see himself through the eyes of my anger and to dislike what he sees, or to produce reciprocal anger or fear by getting him to perceive my anger as a threat or attack” (p. 254).

If I am angry with someone, there is sometimes no telling what I want out of it, if the notion of “want” here is even defined; one merely ought to remember the existence of the phrase “blind anger” to recognize that being angry does not correlate in any sense with an ultimate objective to provoke a targeted emotion from the recipient of that anger. Sometimes, we are just so furious and out-of-mind that there cannot be any end-all objective to fulfill. Indeed there might be times when our anger is targeted in a sense—but it is not always like that. For example, Nagel likens sexual desire to an “appetite”… so is anger an appetite?

The main point here, though, is that Nagel deserves credit for reminding us that there are indeed “levels of mutual awareness” that typify human interactions. But he ought to delve into those other interactions… otherwise, it is us, the Readers, who are tasked with the janitorial duties. In that regard, one critique of Nagel’s theory is that it is too general. If this mutual awareness element of human interaction is quintessential to human conversation and connection, then it must permeate throughout all types of these interactions, including sexual ones. The most specificity he offers us is “Sex has a related structure [of mutual awareness]: it involves a desire that one’s partner be aroused by the recognition of one’s desire that he or she be aroused” (p. 255). Or, in simplified words, “I want you to be aroused by the fact that I am aroused by you.” That is, what distinguishes a sexual interaction from any other kind of interaction is the mutual awareness of sexual arousal and sexual desire.

But, then, what kind of mutual awareness is at play when we’re playing Football, or when we’re working together to debug a piece of code? And—here’s the interesting corollary—what, in these other scenarios, are the corresponding “perversions?” Perhaps we are forced to consider the existence of a “social perversion,” in which an individual has unfortunately been victim to the truncation of this meta-cognitive handshake but in regards to a particular social interaction rather than a sexual one: If it does not make me happy to see that you’re happy, I am no longer correlated with your valence, and thus I suffer from a so-called “socio-philia.” If your elation about your recent workplace promotion leads me to feel jealousy rather than proud of you, am I incriminated of truncating the participation in Duhigg’s meta-cognitive matching principle, and thus am classified as a “jealous-ist?”

Could that help us re-conceptualize narcissists, sociopaths, and psychopaths? Although that suggestion initially sounds quite enticing, it is not evident that these terms stand in any relation to our nascently-invented “social perversions” as a masochist stands in relation to masochism. While we may acknowledge that the coinage of the term “narcissist” derived from repeated observations of a particular social behavior, we must ask ourselves if it is in this manner that the term “masochist” was derived. And how about for a more exotic paraphilia, the list of which is potentially infinite and whose length dwarfs that of the Dark Triad?

Parting Words

Nagel has provided a wonderfully-digestible piece of philosophical writing. I had an excellent time digesting it and thinking about how it might be applied in practice. I certainly learned a lot, and he has given me a lot more to think about. He most certainly has not provided a holistic account of paraphilia, which of course philosophy cannot do alone. Many of my “criticisms” of his writing are really just spontaneous thoughts that I had while I was reading it, rather than calculated, scathing rebuttals aimed to topple his account. As I mentioned in the Introduction, we’ll probably need to combine the efforts from various domains of empirical science with philosophical inquiry to work out the entire story. But we need to also ask ourselves if that is something we really wish to plunge into. Are there some secrets about the human experience that are better left buried?

Let us now see who else has written about paraphilias.

Notes/References:

1. Thomas Nagel is a philosopher working on what’s called the “Mind-Body Problem” in philosophy. One of his most famous essays (on the subject, too) is entitled What Is It Like to Be a Bat? . Consider reading it! It’s an excellent read, and it will readily inaugurate you to the subject of the Mind-Body Problem. If you prefer a video representation of this essay, consider listening to Jeffrey Kaplan’s excellent YouTube video reviewing the essay, entitled What is it Like to be a Bat? - the hard problem of consciousness.

2. “…mind-body debacle…” I’ll use these words ten million times in this article and future ones. It is probably a good idea to get some initiation with the Mind-Body Problem or the so-called Hard Problem of Consciousness. A good way to become initiated in the discussion is to simply read up on the various writings that tangle with this particular issue. To come up with an exhaustive list right now would be exhausting. So, I will once again encourage you to take a look at how Jeffrey Kaplan introduces the subject.

3. “…there exists phenomenological accounts of people thinking themselves to the point of orgasm…” The case study was reported in an academic paper entitled A Case of Female Orgasm Without Genital Stimulation. Have a read! It’s quite fascinating. If you’d like a decent summary of what developed, here is a good sentence from the conclusion: “…it is clear that [orgasms] can be induced without genital stimulation in a ‘top-down’ fashion that reflects both sensory and motor memory and may be activated by dreams, fantasy, and erotic imagery…”

4. “Charles Duhigg calls it the ‘matching principle’” in his book Supercommunicators .

5. The words “valence” and “arousal” are also discussed in Supercommunicators . Roughly speaking, two speakers have a more enjoyable and fulfilling conversation if they match each other’s “valence” (a feeling between happiness and sadness) and “arousal” (energy/intensity of the conversation).

6. “Football” here really means Soccer, but it is time to get with the rest of the world on this (like the Metric System and Celsius) and start calling what it really is: Football. Again, not to make any allusions, of course.

Updates:

1. 2026-09-04: Got this peer-reviewed for release.