Viewed at the biological level, sex is a differentiation that occurs in animals of the higher types and renders each individual either male or female. The male organism is equipped to produce spermatozoa, and the female to produce ova; spermatozoa and ova are in turn ordered to the begetting of offspring. In some lower animals, known as hermaphrodites, male and female characteristics can be exhibited by one and the same individual. In humans, the differences are determined at the time of fertilization and are recognizable, through life, by distinctive physiological, biochemical, and psychological features.

This article is not concerned primarily with the biology, psychology, or sociology of sex, but rather with its philosophy and theology as these are viewed by Catholics. It explains the sex instinct in man, its peculiarly human character, its place in marriage, and its teleology with respect to the individual and to the procreation of the human race,

Sexual Instinct. An unprejudiced analysis of the biological phenomenon of sex reveals its radical difference from other instincts. It has first a kind of depth that neither thirst nor hunger, nor the need to sleep, nor any desire for other bodily pleasure possesses. The charm of the opposite sex, as well as bodily sexual desire, or even *lust, all affect man's personal life in a way completely different from other instincts. They have a mysterious character, something radiating into man's psychical life, that is shared neither by the desire to eat nor by the pleasure that the satisfaction of this desire procures. Above all, sexual ecstasy goes to the very depth of bodily existence; it has in its overwhelming power something extraordinary, to which terrible bodily pains are alone a counterpart.

Apart from its depth, sex possesses an extraordinary intimacy. Every disclosure of sex is the revelation of something intimate and personal; it is the initiation of another into one's secret. In a sense, sex is the secret of each individual; it is for this reason that the domain of sex is also the sphere of *shame in its most noble sense. This again explains the central position of sex in the human personality. It is a voice from the depths, the utterance of something central and of utmost significance. In and with sex, man in a special sense gives himself.

A further mark distinguishing sex from other instincts is the fact that it tends toward contact with another person, that it has, so to speak, a dialogistic character. The sexual desire implies a direction toward the sexual satisfaction of the partner. Aiming at something surpassing one's own bodily realm, it has a definite communal character. Closely linked with this is the uniting element in the shared experience of orgasm, rooted in the very nature of the sex act.

Love and the Beloved. Because of these characteristics, sex is able to become an expression of conjugal *love and to constitute an ultimate personal union, It is not only able to do so, but it is meant to become incorporated into this love; it is destined to serve the mutual self-donation to which spousal love aspires. Indeed, to understand the true-nature of sex, its meaning, and its value, one must start with the glorious reality of the love between man and woman, the love of which the Vulgate says: "If a man gave all the substance of his house for love, he would despise it as nothing" (Ct 8.7).

Just as it is wrong to reduce all types of love to sex, as pansexualist psychologists attempt to do, so it is also erroneous to think that love between man and woman differs from other types of love only through its connection with sex. The specific quality of this love is apparent even before one takes note of the sexual instinct.

It is true that spousal love can only exist between men and women. Yet man and woman are not only different biologically or physiologically; they are also different expressions of human nature, The specific feminine and masculine features of human personality show a complementary character. Man and woman are spiritually ordered toward each other, being created for each other.

In this love, the beloved is more thematic than in any other love, becoming in fact the great human theme. Such a theme expresses itself also in the intentio unionis; although common to all categories of love, this assumes in man its highest tension and its furthest extension. The lover longs for union with the very being of the beloved; he longs for a common life, and the requital of his love assumes an incomparable importance,

Of this spousal and enamoured love Pope Pius XII said: "The charm exercised by human love has been for centuries the inspiring theme of admirable works of genius, in literature, in music, in the visual arts; a theme always old and always new, upon which the ages have embroidered, without ever exhausting it, the most elevated and poetic variations" [Address to Newlyweds (Oct. 23, 1954) Pope Speaks, 21]. Such love, aspiring to bodily union as a specific fulfillment of total union, is a unique, deep, and mutual self-donation. If someone loves another person with this love, he realizes fully the mystery of the bodily union and aspires to it simply because he loves the beloved.

Sex in Marriage. But one must also realize the tremendous commitment implied in this union. It is a self-donation that cannot be separated from marriage, from the will to enter into lasting union with the beloved. The will to be permanently united in marriage results organically from the very nature of spousal love. In sex man gives himself. The conjugal act involves so deep and radical a self-donation that it itself actualizes the indissoluble union to which spousal love aspires. The becoming "one flesh," of the very nature of this reciprocal gift, clearly presupposes not only love, but consensus, i.e., the solemn will of the spouses to bind themselves forever.

The role of sex in spousal love extends, however, much farther than the conjugal act. It manifests itself in the entire realm of intimacy granted to the spouses, in a symphony of effusions of tenderness culminating in this act. The fact that sexual desire often arises without being embedded in spousal love, and that sex can also, when isolated, exert a tremendous fascination, is no argument against its intrinsic relation to spousal love and to marriage. As a consequence of *original sin, the sphere of sex can become a pure actualization of *concupiscence and assume a completely different aspect. Yet the possibility of abuse and perversion of a thing in no way alters its true meaning and essence. For example, it is no proof against the mission, nature, and essence of man's intellect to grasp truth that many are attracted by intellectual activity as a mere display of dexterity or to satisfy pride. Similarly the tendency to isolate sex is no objection against its authentic mission and meaning.

Sex in Isolation. Sex possesses a tender, mysterious, and ineffably uniting quality only when it becomes the expression of something more ultimate, namely, wedded love. As soon as sex is isolated and sought for its own sake, its qualities are reversed. The depth, the seriousness, the mystery disappear, to make room for a fascinating, exciting, and befuddling charm that excludes anything beyond. Wherever sex is encountered in an unlawful form as a temptation, there is heard the siren song of lust, with its honeyed poison. The sublime joy of ultimate surrender—touching, chaste, intimate, and mysterious—that accompanies sex under other circumstances, is then completely absent. Sex is always extraordinary, but its characteristic extraordinariness assumes diametrically opposite forms. At one time, it is awe-inspiring, mysterious, noble, chaste, and free; at another, illegitimate, intoxicating, and befogging.

In sex, there is an element of promise, linked with a vague expectation of happiness. As long as this promise does not tend toward isolated satisfaction, but remains in a reverent submission, awaiting its future as embedded in deep, spousal love, it itself is true. As soon as it is detached from such love—as when one expects the delights of paradise from sex as such—the promise becomes a treacherous one.

Whereas the fascination of isolated sex in its befogging aspect results from original sin, today man is confronted with another deception, viz, the modern approach to sex from a hygienic point of view, as if it were a mere biological need. This amounts to a complete misunderstanding of the sexual sphere. Sex is either a hallowed mystery or a mystery of iniquity; it is never a morally neutral need. So intrinsically is sex connected with the moral sphere that as soon as one tries to deprive it of its moral significance, he also deprives it of its extraordinariness. The amoral approach is thus as sinful as the immoral approach; what is more, the former implies a radical blindness to the nature of sex, and leads to hopeless boredom.

Those who treat sex as the primary reality that can be understood in itself without recurring to spousal love thus fall prey to a fatal error. They are blind both to the nature of love and to the nature of sex. Ironically enough, in trying to reduce everything to sex, they fail to understand the nature of sex itself.

Teleology of Sex. An important mark distinguishing sex from other instincts and biological appetites is the type of finality it involves, All instincts, it should be noted, have teleological meaning. They serve as a means for an extrinsic end, and in so doing also fulfill their intrinsic or subjective finality. Instinctive desires tend toward their satisfaction as toward a subjective or experienced end. Thirst, for example, tends toward the satiety offered by drinking. But thirst also serves the body's need for water. The subjective end serves the objective end; one could say that the former is ultimately a means to the latter, as extrinsic to it.

In sexual desire such a twofold finality is also found. The subjective, experienced finality tends toward sexual satisfaction; the objective finality is directed toward procreation. When dealing with animals, one can consider sex as an exclusive means for procreation; where man is concerned, the relationships between sex and procreation become subtler and deeper.

Intrinsic Finality. With man, the subjective teleology in the sexual instinct is deeply involved with psychical and spiritual experiences. By its very nature it is ordered toward conjugal love, and toward the consensus organically resulting from this love. This gives human sex a twofold immanent or subjective teleology: one tending toward the experience of orgasm; the other directed toward the opposite sex. The longing for sexual pleasure is typically a bodily experience, whereas the attractiveness of the other sex, the charm of sex, is a psychical experience. Each is normally linked to the other, and the marks of depth, centrality, and intimacy apply to both. Both are ordered to serving as expressions of spousal love and as fulfillments of the marriage bond. Both are necessarily misunderstood in their real meaning when they are seen as self-contained instincts.

Just as the direction toward orgasm can only reveal its true character when formed by spousal love and absorbed by its function to effect marital union, so also the attractiveness of the opposite sex attains its authentic meaning only in spousal love. For the true lover, all the general charm of femininity or masculinity actualizes itself in the individuality of the beloved. For him, the unique and individual personality of the beloved embodies the general charm in all its psychophysical plenitude and depth. The beloved person is the theme: the attraction of femininity or masculinity is completely incorporated in mutual self-donation.

Moreover, Christ has endowed marriage with the character of a Sacrament, making it something holy and a source of special graces. This confers a completely new dignity on the bodily union. Though marriage is validly established by the consensus, it is consummated only by the marriage act, assuming through it the character of a strictly indissoluble union. Its essential role in the consummation of the Sacrament clearly reveals the dignity to which the conjugal act has been elevated.

Extrinsic Finality. To this sublime union God has confided the coming into being of a new man, a cooperation with His divine creativity. Such deep mystery calls for reverence and awe. It is no accident that God has invested an act of this kind with creative significance. As God's love is the creative principle in the universe, so love is everywhere creation. Thus there is profound significance in the nexus—at once symbol and reality—whereby, from the creative act in which two become one flesh, both from love and in love, a new human being proceeds. This mystery of the profound link between love and procreation sets forth the gravity of artificial birth control in a new light.

The difference between the finality of other instincts and the one linking sex to procreation thus begins to disclose itself. The finality between the conjugal act and procreation is superabundant, and not merely instrumental. This becomes clearer on examining the nature of the principle of superabundance and its difference from mere instrumentality.

It cannot be denied that one end of knowledge is to enable man to act; his entire practical life presupposes knowledge. Yet a still more sublime end of knowledge is to enable him to attain the moral perfection and sanctification that is requisite for his eternal welfare. While knowledge of itself has a meaning and value of its own, its relation to the ends it serves has the character of superabundance. Its orientation differs markedly from the instrumentality incorporated into a surgical instrument as a means for operating, or into money as a means for procuring goods, or into teeth as a means for masticating food. In instrumental finality, the end is the exclusive explanation of the means; in superabundant finality, the good serving the end has also a justification and a value in itself.

The conjugal act furnishes a unique fulfillment of spousal love in mutual self-donation. The same act, in itself constitutive of the union, is superabundantly the source of procreation. Thus one must speak of procreation as the end of sex in a sense different from that of mere instrumental finality.

Christian View of Sex. The Christian perceives the true mystery of sex; he perceives its depth, its seriousness, and its intimacy. He understands implicitly its ordination to serve the ultimate union in marriage, and the coming to be of a new human being, He is aware of the high value that it embodies as effecting mutual self-donation in wedded love, and as source of procreation, He clearly perceives the fearful profanation that every abuse of sex represents, the deadly poison defiling the soul and separating it from God; this is what sexual pleasure generates when treated as its own end. He shrinks from any contact with sex as soon as it is thus isolated and rendered poisonous. He possesses a deep reverence for its mystery, remaining at a respectful distance when not called by divine vocation to enter its domain. His is not a Puritanical or Manichean despisal of sex; for him, the conjugal act is neither something lowly, tolerated in marriage for the sake of procreation; nor is it merely a "normal" claim of the body finding in marriage its legitimate outlet.

The Christian understands that an ultimate interpenetration of sex and conjugal love takes place in mutual self-donation; sexual experience is thus not something parallel to love, but is absorbed and elevated by this love. Moreover, the Christian understands that sex belongs in a special manner to God, and that he may make such use of it only as explicitly sanctioned by Him. Only with God's express permission may he eat of the fruit of this tree. The awareness of this fact engenders a reverence that pervades his approach to sex even within the marriage bond, This enables him clearly to understand the sinfulness of artificial birth control, with its irreverent severing of the deep link between the ultimate love union and procreation. He understands the tremendous dignity with which the conjugal act is endowed by marriage's being a Sacrament. This implies that his very love calls for being transformed in Christ. He is aware of the fact that only in Christ and through Christ can he live up to the full glory and depth to which this love by its very nature aspires. As Pius XII has stated:

But what new and unutterable beauty is added to this love of two human hearts, when its song is harmonized with the hymn of two souls vibrating with supernatural life! Here, too, there is a mutual exchange of gifts; and then . . . through natural affection and its impulses, through a spiritual ration and its delights, the two beings who love each other identify themselves in all that is most intimate in them, from the unshaken depths of their beliefs to the highest summit of their hopes. [Ibid.]

See also CHASTITY; CONTINENCE; EMOTION; LOVE; MODESTY; VIRGINITY.

Bibliography: D. VON HILDEBRAND, In Defense o/ Purity (New York 1931; repr. Baltimore 1962); "Marriage and Overpopulation," Thought 36 (1961) 81-100. F. WALTER, Der Leib und Sein Recht im Christentum (Donauwörth 1910). Pius XII, The Pope Speaks, ed. M. CHINIGO (New York 1956).

[D. VON HILDEBRAND]