Novels are arguably about two subjects: sex and death. This isn’t an original or unorthodox observation; Leslie Fiedler famously propagated it in Love and Death in the American Novel, which was published in 1960. The reasons why we’re drawn to those subjects over and over again are less well-developed, but some good answers come from evolutionary biology. Going back to Darwin and The Descent of Man, and Selection in Relation to Sex, we’ve known that organisms need to do two things to propagate themselves: survive and reproduce. Not coincidentally, those two items map neatly onto the fascination in narrative fiction with death (and who should be killed and under what circumstances) and sex (and who it should be had with and under what circumstances).

Novels ceaselessly interrogate and illuminate both fields. I think people are drawn to those subjects because the stakes are inherently high for us, our genes, and our communities. If we die, our genes go with us, and, according to Richard Dawkins’ The Selfish Gene, we’re the result of a long chain of ancestors who managed to send out genes into the future. Viewed in one light, we’re simply vehicles for propagating those genes successfully. One could argue from there that our communities are platforms—in the sense Steven Berlin Johnson develops in Where Good Ideas Come From—that allow us to survive and reproduce successfully. Communities that are more successful as platforms tend to spread; those that aren’t, whither, or are overtaken by communities that do. Historically speaking, this has often happened in the context of violence, cruelty, slavery, and the like, especially on behalf of the west against peoples of other cultures, as Jared Diamond points out in Guns, Germs, and Steel: The Fates of Human Societies.

But for my argument regarding the novel, I want to focus on individuals, small groups, and genres. Regarding the latter, one can essentially map tragedies onto stories dealing with death and comedies onto stories dealing with sex and sex mores. The content of those stories change—what tragedy meant to Shakespeare is probably somewhat different than what it means to, say, Cormac McCarthy. And the sex comedies of Jane Austen, with their primness, their refusal to name the act itself, and their distaste for contemplating the act of intercourse outside of marriage (how shocking it is when Lydia absconds in Pride and Prejudice!) are quite different from those in Bridge Jones’ Diary or Alain de Botton’s On Love, both of which assume sex before marriage is normal and that marriage isn’t an essential part of life. The content of the stories change while their overall thrust and the fundamental subjects remain the similar. Unless humanity reaches a technological singularity (which seems unlikely to me; as Tyler Cowen likes to say, it’s 2011 and we still have web browsers that crash), I doubt we’re going to see a shift away from novels that focus on sex and death as the greatest issues that humans face. We’re fascinated by the shifting, dialectical rules surrounding both sex and death and how they may be deployed because they have such profound consequences for us and our genes.

So why don’t more people discuss this explicitly in novels?

Evolutionary biology offers some of the tools we need to analyze what drives humans in terms of sexuality and survival. I’m surprised more literary critics don’t want to or try to cross pollinate with evolutionary biology, since, as stated in the first sentence of this paragraph, evolutionary biology gives us another set of methodological principles with which to interrogate texts. The set of tools literary critics need has started to be developed by William Flesch in Comeuppance: Costly Signaling, Altruistic Punishment, and Other Biological Components of Fiction. But fundamental questions remain unanswered—like how individual variation functions within an amorphous system without definite boundaries. As with psychoanalytic criticism, however, we can still take overall ideas (like: “males and females differ in their average mating strategies because women bear the greater cost of childbirth and childrearing”) and work to apply them to literature.

This doesn’t mean that we should automatically assume a one-to-one correlation between any action a character in fiction undertakes, or that characters (or their authors) are even aware of their own motivations; when Emma is trying to set up everyone in Highbury, she’s partially trying to maintain the class structure of her time, but she’s also trying to maximize the reproductive success of the individuals she knows (and herself) through finding “appropriate” matches. Since Freud, the idea that people (or characters) understand their motivations has been a suspect premise anyway. And since Derrida, if not earlier, the idea that one can neatly create separate categories like “death” and “sex” has become suspect. But that both drive characters and intertwine in unusual, fractal, and unpredictable ways is true. We need to track, understand, and evaluate those ways better. Psychoanalytic criticism gives us a set of tools to do so.

Characters’ underlying drives can’t be ignored. Nor can what readers find most rewarding in fiction be ignored. When in doubt, ask what is at stake regarding sex, death, or both. It would be a mistake to create a reductive algorithm that merely says, “everything a character does is related to their biological reproduction or their survival.” It would also be a mistake to think that every character interprets the drive to survive and reproduce in the same way, or that evolutionary biology itself has a single, underlying set of rules: its own rules are under constant interrogation as new evidence emerges to support or refute existing claims. But the answers that emerge from asking questions about why characters are so tuned in to the sexuality of others goes beyond economic exchange, mate value, and culture, and into what a given character thinks a set of rules will do to his or her own chances at reproducing and thriving.

To use Emma again, the characters in that universally or almost universally believe that marriage is in their best interests and therefore the best interests of those around them. They do not question the value of the institution, as later writers will do; by the time we come to George Eliot and Flaubert, novelists have begun to do so in earnest (as Tony Tanner points out Adultery in the Novel: Contract and Transgression). By now, novels are asking questions about what happens to relationships when marriage is an option, not a given, and when virtually any life course is open to people as far as sexuality is concerned. If you write a contemporary novel that deals solely with the momentous decisions around who a woman will marry (as in Jane Austen), you won’t be engaging the world in which contemporary Western characters live. You’re dealing with sex, but not in a way that resonates with the social fabric for most people. The drive (“reproduce successfully”) remains even if the means have changed. Whether you’re analyzing or writing novels, you better pay attention.