Sex is a function of the body, isn’t it? It’s all biology. 

Just biology, nothing more?

Without your body you can’t have sex.

Indeed, but without your body you can’t speak – and yet speaking is more than biology. Without your body you can’t draw – and yet drawing is more than biology. Without your body you can’t sing…

Alright, alright. So you are saying that a sexual act also has… has what?

Meaning. Speaking is not just making sounds, but sounds that have a meaning. Drawing is not just making shapes, but shapes that mean something.

So a sexual act is a bodily action that has some meaning?

Maybe. It’s worth finding out, isn’t it?

What kind of meaning?

Now, that’s a good philosophical issue.

The promise and failure of sex
Jean-Paul Sartre (1905-1980) was an important French existentialist philosopher, political activist, novelist and playwright. In his student years, while studying philosophy and other fields at École Normale Supérieure, he met Simone de Beauvoir, who became his life-long companion and lover. The two maintained an ongoing open relationship, and developed philosophies that were close in spirit. In World War II Sartre was drafted by the French army, and was taken prisoner by German forces. On his return to Paris, he participated with other intellectuals in underground activities, and also published his main philosophical book Being and Nothingness (1943). At different times in his life he was actively involved in various social causes such as communism, anti-colonialism, and human rights. In 1964 he was awarded the Nobel Prize for literature, but declined it. He died in 1980 from a lung condition. 
    
The following text is adapted (and slightly simplified) from the chapter “Concrete Relations with others” in Sartre’s book Being and Nothingness (1943). For Sartre, sexual desire wants to “appropriate” the lover, in other words to catch and possess the lover – not just the lover’s body (the objective facts, the “flesh”) but also the lover’s free consciousness. In this limited sense, sexual desire promises the possibility of encountering the entire person, but this promise is doomed to fail. You cannot possess a free consciousness.
       In sexual desire, Sartre explains, I am becoming “incarnated.” I am now a consciousness in my body and through my body. Moreover, in sexual desire I am inviting the other to be incarnated too. This means that when my body meets the lover’s body, we are not objectifying each other, we are not making each other into things. We relate to each other’s consciousness through the body.
       But this, Sartre says, cannot succeed. As soon as we start acting on this desire, as soon as we engage in sexual acts, I am no longer a consciousness incarnated in the body. Either I become a consciousness or I become an object. If I focus on my pleasure, then I make my lover an instrument for my pleasure. In contrast, if I focus on giving pleasure, then I objectify myself as an instrument for my lover’s pleasure. (Or, of course, I can alternate between the two.) In this sense, sex is necessarily a “perversion.” The extreme form of this perversion is either sadism – making the other an object of pleasure, or masochism - making myself an object.

 
In desire, I make myself flesh in the presence of the Other in order to appropriate the Other’s flesh. This means that it is not just a question of my grasping the Other’s shoulders or thighs, or of my pulling a body closer against me. It is also necessary for me to apprehend her body through this particular instrument which is my body as it produces the sexual desire. In this sense, when I grasp these shoulders, it can be said not just that my body is a means for touching her shoulders, but also that through her shoulders I discover my own body in a fascinating revelation of facticity [pure facts] – in other words, my own flesh. Thus, desire is the desire to appropriate a body, and this appropriation reveals to me my body as flesh.
[…]

Desire is an attitude that aims to enchant. Since I can grasp the Other only as an objective fact, the problem is to catch her freedom within this facticity. […] So the Other’s consciousness must be expressed on the surface of her body, and be extended throughout her body, so that by touching her body I will finally touch her free subjectivity. This is the true meaning of the word “possession.” I certainly want to possess the Other’s body, but I want to possess it as “possessed” by consciousness, in other words, her consciousness when it is identified with her body. This is the impossible ideal of desire: to possess the Other’s free consciousness as pure consciousness – and at the same time as a body.
[…]
Desire is an invitation to desire. Only my flesh knows how to find the road to the Other’s flesh, and I put my flesh next to her flesh in order to awaken her to the meaning of flesh. When I caress her, when I slowly put my inert hand against her side, I am making her side feel my flesh, and this can be achieved only if it makes itself flesh. […]
       Nevertheless, desire is doomed to failure. […] Pleasure (just like a pain that is too strong) creates reflective consciousness [consciousness of itself] which is “attention to pleasure.” But pleasure is the death and the failure of desire. It is the death of desire because it is not only the fulfillment of desire but also its limit and its end. […] Pleasure closes the door on desire because it creates a reflective consciousness of pleasure, whose object becomes reflective enjoyment. In other words, the attention to the incarnation of consciousness is now being reflected upon, and therefore consciousness forgets the Other’s incarnation. This is because consciousness, by incarnating itself, loses sight of the Other’s incarnation, and its own incarnation absorbs it to the point of becoming its ultimate goal. In this case, the pleasure of caressing is transformed into the pleasure of being caressed. […] Immediately there is a rupture of contact, and desire misses its goal.
[…]
Yet conversely, desire is at the origin of its own failure when it is a desire of taking and of appropriating. […] Desire is the desire to appropriate this incarnated consciousness. […] But by the very fact that I now attempt to grab the Other’s body, to pull it toward me, to hold it, to bite it, my body stops being flesh and its becomes again the synthetic instrument which I am. And in the same way, the Other stops being an incarnation. She becomes again an instrument in the world which I apprehend in terms of its situation. Her consciousness, which played on the surface of her flesh and which I tried to taste with my flesh, disappears under my sight. […] This does not mean that I stop to desire, but that desire has lost its content. It has become abstract. It is a desire to handle and take. I insist on taking the Other’s body, but this insistence makes my incarnation disappear.

Sexuality as a language
Robert Solomon (1942-2007) was an American philosopher. He taught philosophy at several universities, mainly at the University of Texas. He wrote many books and articles about 19th-20th European philosophy, emotions, and love. Some of his writings were written together with his wife, also a philosophy professor. He died at the age of 64 from pulmonary hypertension. 
    
The following text is adapted (with some sentences simplified) from Solomon’s article “Sex and perversion” (1975), in which he argues against the concept of “sexual perversion.” To understand Solomon’s rejection of this concept, we should note that he has a “cognitivist” approach to emotions. As he argues in many of his writings, emotions are not opposed to cognition and rationality. Love is not a blind force, because it expresses thinking, choosing, learning, as well as cultural ideas. The same applies to sexuality: It is not a blind natural appetite or instinct. Sexuality should be seen as a language, as a form of communication. This is why it doesn’t make sense to talk about certain sexual acts as “perversion” – after all, perversion means going against what is “natural,” but sexuality is not just something natural. It is much more than physical acts because it also expresses meaning. Since sexuality is a form of communication, it can be in good taste or bad taste, vulgar or subtle, offensive or pleasing, communicative or disruptive, but not a perversion of nature. What people regard as a perversion is usually communication failure due to incompatible languages.

 
Sexuality is primarily a means of communicating with other people, a way of talking with them. It is essentially a language, a body language, in which we can express gentleness and affection, anger and resentment, superiority and dependence – and we can do so much more briefly than in a verbal form, where expressions are necessarily abstract and often clumsy. If sexuality is a means of communication, it is not surprising that it is essentially an activity performed with other people. And, if it is our best means to express dominant feelings and relationships that are often difficult to verbalize, then it is not surprising that sexuality is one of the most powerful forces in our lives.
[…]
The basic vocabulary of body language is the gesture, which might be an activity, but it is usually an expression or a position. The gesture is the bodily equivalent of a sentence. […]  Body language, like verbal language, expresses a capacity that is not equally shared by everyone. Some people are inarticulate, even retarded, others are brilliant and creative. […] Most people, needless to say, like in speech, know only the elements of language that are most common, most easily articulated, least committal, and least personal. Some people, including dancers by profession, articulate their body language with such perfection that every gesture is an exact and perfect expression.

Whatever else sexuality might be, and for whatever purposes it might be used or abused, it is first of all a language. When spoken, it tends to result in pregnancy, in scandal, in jealousy and divorce. It is a language that, like verbal language (but sometimes more effectively), can be used to manipulate people, to offend and flatter them. It can be enjoyable, not just because of its phonetics – which are neither enjoyable nor meaningful in themselves, but because of WHAT is said. One enjoys not just the tender caress, but also the message which it carries. And one welcomes a painful push or bite not because of masochism, but because of the meaning.
[…]
Like dancing, sexuality is an expression and development of everyday movements, which is capable of open-ended refinement and individual variation, like poetry of the body. But while dancing relates to the audience as anonymous and its message is impersonal, sexuality is always personal and deeply revealing. One might argue that sexuality is much less refined, must less an “art” than dancing. But this, I would counter in response, is a sign of our general vulgarity and lack of self-consciousness in all things important. Nothing can or should be a more human form of art than intimate communication.
[…]
Vulgarity, as in every art form, can be charming in small quantities but offensive when it is over-done. Since sex is a language which demands subtlety and artfulness, too much frankness and vulgarity are, if not perversions, at least gross abuses of the language, just as very bad poetry can still be considered poetry. This explains, for example, why explicit sexual propositions and subway exhibitionism are in general offensive, something which would not be understandable if we regarded sex, as most people do, as an “appetite.” […] Sexuality is very different from the “animal” instinct in us, and it appears only in those human activities where considerable refinement is possible. Sexuality permits vulgarity only because it is a matter of refinement. Thus, direct sexual propositions and subway exhibitionism are offensive, not because they deviate from some “normal sexual aim” but because they are vulgar. They are like an anti-poetry poet who writes an entire poem that consists of a single vulgar word, or a comedian who has to explain his obscene jokes explicitly. Similarly, sexuality lies in subtlety.

Male and female sexualities shaped by society
Simone de Beauvoir (1908-1986) was a French existentialist philosopher, writer, and political activist. During her studies she met Jean-Paul Sartre and the two became life-long friends, intellectual companions, as well as lovers who maintained an open erotic relationship. She wrote many novels and essays, and was also involved in the French women’s liberation movement. She died of pneumonia at the age of 78, and was buried next to Sartre in Paris. 
    
The following text is adapted from Simon de Beauvoir’s famous book The Second Sex (1949), an influential philosophical work on woman’s condition. A major theme in this book is that woman has been shaped by society to become an Other – defined not by herself but in relation to man, as being the creature who is different from man, as the “second” sex. She has also been forced to give up her subjectivity, her “transcendence” – the human capacity to go beyond the facts and freely give meaning and value to things in life.
        All this applies to sexuality too. Differences between man’s sexuality and woman’s sexuality are not the result of biological factors but of complex social processes which shape woman and her sexuality. Of course, biological differences exist, but the crucial question is how society interprets and treats these differences. De Beauvoir analyzes in detail the development of these two sexualities, and the following text contains a few examples of the process. Whether or not we accept her specific analysis, on a more general level she offers a provocative idea: that your sexuality is not simply the result of your personal tastes or urges, but of social factors that shape your identity and sexuality.

 
From Book 2, Chapter 12: Childhood
       One is not born a woman, but rather becomes a woman. No biological, psychological, or economic fate determines the character of the human female in society. Civilization as a whole produces this creature who is between male and eunuch, and who is described as feminine. Only the intervention of somebody else can establish an individual as an Other.
[…]
Anatomically, the boy’s penis is suitable for this role. It projects free from the body and seems like a little natural toy, a kind of puppet. Adults will give value to the boy, then, when they give value to his “double” [his penis with which he identifies]. […] For the little girl, things are very different. Mothers and nurses feel no reverence or tenderness toward her genitals. They do not direct her attention toward that secret organ, invisible except for its covering, that cannot be grasped by hand. In a sense, she has no sex organ. She does not experience this absence as a lack; evidently, her body is quite complete for her. But she finds herself situated in the world differently from the boy, and a constellation of factors can transform this difference, in her eyes, into an inferiority.
[…]
Thus, the passivity that is the characteristic of the “femenine” woman develops in her from the earliest years. But it is wrong to assert that a biological fact is concerned. It is, in fact, a destiny imposed upon her by her teachers and society. The great advantage enjoyed by the boy is that his mode of existence in relation to others leads him to assert his subjective freedom. […] In woman, on the contrary, there is from the beginning a conflict between her autonomous existence and her objective self, her “being-the-Other.” She is taught that to please she must try to please, she must make herself an object. She should therefore renounce her autonomy. She is treated like a live doll and is refused liberty.

 

From Chapter 14: Sexual initiation
       Sexual pleasure in woman, as I have said, is a kind of magic spell. It demands a complete letting go. […] She longs to abolish the separateness that exists between her and her male. She longs to melt with him into one. As we have seen, she longs to remain subject while she is made object. Since she is more profoundly beside herself than man, since her whole body is moved by desire and excitement, she retains her subjectivity only through union with her partner. Giving and receiving must combine in both of them. If the man limits himself to taking without giving, or if he gives pleasure without receiving, the woman feels that she is being maneuvered, used. Once she realizes herself as the Other, she becomes his non-essential Other, and then she has to deny her otherness.
       This explains the fact that the moment when the two bodies separate is almost always distressing for the woman. After coition, the man always dis-owns the flesh, regardless of whether he feels happy or depressed, the victim of nature or the conqueror of woman. He becomes once more an honest body. He wants to sleep, take a bath, smoke a cigarette, go out for fresh air. The woman wants to prolong the bodily contact […] “Was it enough? You want more? Was it good?” – the fact that he asks such questions emphasizes the separation, it changes the act of love into a mechanical operation directed by the male. And that is, indeed, why he asks them. He really seeks domination much more than fusion and mutuality.
[…]
The erotic experience dramatically reveals to human beings the ambiguity of their condition. Through it they are aware of themselves as flesh and as spirit, as the Other and as the subject. The conflict has a more dramatic shape for woman, because at first she feels herself to be object and she does not immediately realize a sure independence in sex enjoyment. She must regain her dignity as a transcendent and free subject, while assuming her bodily condition – this enterprise is full of difficulty and danger, and it often fails. But the difficulty of her position protects her from the traps into which the male easily falls. He is an easy victim of the deceptive privileges given to him by his aggressive role, and by the lonely satisfaction of the orgasm. He hesitates to see himself fully as flesh. Woman lives her love more authentically.