The unmistakable feeling that we call love in English seems to descend on us out of nowhere when we least expect it, even though we may not want it, since it alters how we will subsequently live our lives. It is an irresistible inner force. Unlike the set of biological urges that we call sex, and which we can indulge and gratify through carnal activities, love keeps us on an emotional leash that defies common sense. Of course, love and sex often go together, with one influencing the other, physiologically and emotionally. Since the beginning of time people have nonetheless constantly conceptualized love as being separate from sex, and thus, a departure from our animal instincts—that is, as something unique that transcends our biology. In many species, sexual desire is stimulated by signals emitted during estrus (a recurring period of sexual receptivity and fertility). People experience desire outside of any fixed biological period, which induces them to pursue sexual activities at any time. In acknowledgment of the universal differentiation felt to exist between love and sex, Italian Renaissance philosopher Marsilio Ficino coined the term “Platonic love,” alluding to love as a divine or spiritual force that is different from sex and that can exist separately from it.¹

Animals may also experience a form of love, but we can never be sure what “love” in different species means because we tend to interpret emotional responses in animals in human terms. Charles Darwin wrote about chimpanzees displaying courtship behaviors that seemed very similar to human romantic ones.² However, it is a stretch to assume that the two are identical, although they certainly are comparable. In her classic book, In the Shadow of Man, the renowned primatologist Jane Goodall writes about two apes as follows: “I saw one female, newly arrived in a group, hurry up to a big male and hold her hand toward him. Almost regally he reached out, clasped her hand in his, drew it toward him, and kissed it with his lips.”³ Again, the description makes sense in human terms, unconsciously assuming an equivalency between humans and apes. Different species share certain life schemas with humans, and these may involve overlapping emotional qualities. But equating them is risky. As the biologist Jakob von Uexküll argued in his pivotal work on the animal mind, we can never really know what animals truly think and feel; we can only compare their behaviors to ours and make projections and analogies.⁴ Animals display astounding intelligence, emotions, creativity, and other traits that sometimes appear to overlap with human ones. And they may indeed possess a form of love that is analogous to human love. But all we can do is compare it to ours, interpreting it on our own terms, not on their behalf.

Many of the ancient mythic stories dealt expressively with the emotional tug between love and sex in ways that implied that this opposition was directive of human destiny. For instance, Aphrodite, the Greek goddess of love and beauty (Venus in Roman mythology), represented the interplay between spiritual love and sexual seduction through the various stories told about her. In Homer, Aphrodite was married to Hephaestus, the blacksmith of the gods. But many other stories give her other lovers, including Ares, the god of war, and the Trojan prince Anchises. In later myths, she was also portrayed as the mother of the love god Eros. Her counterpart was Diana, the moon goddess representing various aspects of women’s lives, including childbirth. Diana symbolized chastity and modesty. When Actaeon saw her bathing—a voyeuristic sexual act—she took revenge on him by changing him into a stag. He was immediately attacked and killed by hounds, an act of divine retribution for violating the purity of love. Aphrodite and Diana are mythic figures standing for the intrinsic opposition, yet intricate relation, between sex and love, sensuality and tenderness, the sacred and the profane.

The early myths begged an abiding question that still plagues human consciousness: What is love? Even finding a surface definition is virtually impossible. All we can do, plausibly, is document and examine the multitude of expressive artifacts (words , symbols, stories, myths, poetry, etc.) it has enfolded throughout time. In its romantic sense—which is the one that is of interest in this book—it stands for a feeling of intense, passionate desire toward someone. It is perceived commonly as irrational, impelling individuals “in love” to act in ways that are unconventional and even perilous. The ancient Greek philosophers actually identified six forms of love—eros (sexual love), philia (love of friends), ludus (playful love), agape (spiritual love), pragma (longstanding love), and philautia (love of the self). It was the opposition and interconnection between eros and agape that found its way into the plots of many of the early stories. Pragma also played a role in them, but not as prominently. As the late psychoanalyst Erich Fromm cogently argued, we have always assigned too much importance to “falling in love,” rather than pragma , or “standing in love,” thus failing to make an effort to give love rather than just receive it.⁵ Of course, it could well be that pragma emanates from agape , at least when it “works out,” to use a common metaphorical depiction of this truly enigmatic emotion.

One of the most widely-known myths based on the love-sex opposition is the story of Cupid in Roman mythology, identified with the Greek god Eros. Cupid was one of Venus’ sons, and in one version his story is all about the antagonistic emotional tug between love and sex, cruelty and joy. Cupid’s cruelty is manifest in his treatment of his wife, the beautiful princess Psyche. He forbade her ever to try seeing what he looked like, refusing to be with her except at night in the dark. One night, as Cupid slept, Psyche lit a lamp so she could take a look at him. He awoke and fled in anger, abandoning his beloved, becoming heartbroken and taking out his anger on others, by either uniting or dividing them romantically with his arrows, allowing fate to determine which of the two would be realized. The myth of Cupid is essentially an ancient imaginative treatise on the ambiguities, incongruities, and contrastive vicissitudes that we associate with love and sex. As D. H. Lawrence once put it, our tales of love are antidotes to our disappointments and delusions: “And what’s romance? Usually, a nice little tale where you have everything As You Like It, where rain never wets your jacket and gnats never bite your nose and it’s always daisy-time.”⁶

Along with the story-tellers, the ancient philosophers became intrigued with the meaning of love and especially how it may have originated in our species. In the fifth century BCE, Empedocles saw love as a physical force that causes the elements in the universe to come together as compounds, counteracting a force that he called “strife,” which causes the compounds to break up. He believed that the universe undergoes a continuous cycle from complete unification under the domination of love to complete separation under strife, and that this cycle occurs in humans as well after they experience love and its delusions.⁷ Some philosophers saw love, instead, as a form of madness—a perception that extends right through to modern times, as can be seen in our popular discourse about love (“madly in love,” “crazy in love,” “to lose one’s mind,” etc.). In Plato’s Symposium, written between 385 and 370 BCE,⁸ love is portrayed as an obsession by the guests at Plato’s imaginary banquet, since it arouses irrational passions that could lead to illogical self-immolating behaviors. At the banquet, the playwright Aristophanes ascribes love to a revenge of the gods. Originally, he claims, humanity had a tripartite nature—some people were male, some were female, and others half male and half female. This made humanity strong and resistant to the will of the gods. As a result, the latter intervened to set the conditions that defined our fallible sexual nature—males searching for males, females searching for females, and males and females searching for each other.

The theme of love-as-an-obsession w...