In Fred Hoyle's classic science fiction novel, ''The Black Cloud" (1957), a super-intelligent, intergalactically roaming gas cloud passes through our solar system. Contact is briefly established with a primitive planetary population (i.e., us). After effortlessly and instantaneously ingesting the entirety of human knowledge, the cloud asks amiably: ''Will you please resolve this paradox? A very large proportion of your literature -- forty percent, I estimate -- is concerned with what you call 'love.' Yet nowhere in literature could I find out what 'love' consists of. This led me to assume that 'love' must be something rare and remarkable. Can you imagine my surprise when at last I learned from medical textbooks that 'love' is a very simple, ordinary process, shared by a great variety of other animals?"
Not simple at all, according to the philosopher C.D.C. Reeve. Animals may experience some sort of intimacy or relatedness, but nothing as complicated and demanding as ours. Because gestation and infantile dependence last so much longer in humans than in animals, we have an unconscious life. This is where Reeve begins his subtle account of love's confusions.
''Love is whatever develops from, and somewhat recapitulates, a child's relationship with his mother." That sounds reductive, but it's not. Infants think as well as feel; and infantile thinking underlies adult thinking, just as infantile sexuality underlies adult sexuality. Somehow -- we don't yet know how, and Reeve's Freudian account, though plausible, is not fully convincing -- an infant forms images, first of itself and then of the outside world. These images are the characters (''inner-baby," ''inner-Mommy") in a drama that takes place in the infant imagination. The plot elements in this drama are the infant's needs and the mother's help and approval. As the plot thickens -- with the mother's occasional disapproval, absence, even neglect, the infant's answering hatred, and eventually the father's competing, threatening presence, as well as new infantile needs (for bodily control, not merely food) -- new characters are added (''bad inner-baby," ''bad inner-Mommy," ''inner-Daddy," etc.), along with new plot twists. The infant's dramaturgy is called ''fantasy"; enumerating its techniques is one main function of psychoanalytic theory.
''We are actors," Reeve writes, ''playing roles for actors playing roles for us." The scripts are continually revised, of course, but elements of the primal drama, the original script, keep reappearing. Reeve has also found a clever new metaphor: ''The love story which is woven from the materials about love in the files our society attaches to the word 'love' we may call 'conventional love.' When we love, we -- improvising to some extent -- act it out. In the files each of us ends up attaching to that word as a result of our earliest lessons in love, however, lies a different story: 'infantile love.' Unlike its conventional descendant, infantile love is learned in a context of total helplessness and dependence on another. But such life-and-death situations heighten and intensify experience and make it more memorable: in wars, and the games that simulate them, the heart beats faster. If, as we live out the complex story encoded in both files, both sorts of love are being played . . . simultaneously, reality somewhat satisfies our infantile desires, our experience is infused with the intense pleasures of infancy, and we feel vigorous and alive."
Understanding the persistence of the past is only the first of the rewards of ''Love's Confusions." Reeve is also good -- good enough to make an honest reader squirm, at times -- on anxiety, envy, jealousy, sentimentality, narcissism, and pornography. And it's a pleasure watching him engage with great texts, not only of philosophy -- Plato's ''Symposium," Augustine (there's a thrilling description of orgasm from ''The City of God"), Kant, Kierkegaard, Iris Murdoch -- but also literature: Homer (Reeve astutely explains why Odysseus gave up Calypso to return to Penelope, which many a shallow male, including this writer, has undoubtedly asked himself), Proust (of course), Junichiro Tanizaki, Philip Larkin, Milan Kundera, and Norman Rush's magnificent ''Mortals."
The past returns again in ''Love, Sex and Tragedy." Classics professor Simon Goldhill tells us that the point of his book was summed up pithily by Cicero: ''If you do not know where you come from, you will always be a child." Politically, philosophically, and artistically, Greece and Rome are where we come from, as Goldhill has no trouble showing. But what about love? Do we really have anything to learn from the ancients? After all, ''Greek love" was very peculiar and is now extinct; and as for the Romans -- well, didn't they behave rather . . . unspeakably?
What we can learn is what the Greeks called ''the care of the self." That sounds like contemporary narcissism, but it's not. It's a rigorous, austere discipline of self-cultivation, intellectual, emotional, and physical, as far from mere hard bodies as from Southern California sybaritism. It's the yoga of the West. The fact that it has been so thoroughly lost sight of is perhaps one more explanation of contemporary American childishness.
Rather than end on so unloving a note, here's a happy idea. By my estimate (wholly unreliable, and, in fact, just made up), the average lover will spend $25.15 on his or her beloved this Valentine's Day. That (an extraordinary coincidence!) is exactly the price, including Massachusetts sales tax, of ''Love's Confusions." Not only is the book less fattening than chocolates; it's also, in my opinion, more aphrodisiac.
George Scialabba is a regular contributor to the Globe Books section.