The Atheist's Guide to Reality_ Enjoying Life Without Illusions - Alex Rosenberg [65]
Long ago, nature provided mammals with emotions. Darwin was among the first naturalists to study them carefully. One of his last books was titled The Expression of the Emotions in Man and Animals. He recorded there the remarkable similarity between human, primate, and canine expressions of emotion. Emotions must go back very far into our evolutionary tree. In humans, natural selection has co-opted emotions to enforce norms. These norms that emotions enforce are often good for our genes but not for us. We honor them in spite of the disservice they do to our interests. Love and jealousy are good examples. Both are strong emotions and are often very high in short-term costs for guys and highly beneficial to the maximization of their (long-term, multigenerational) genetic fitness.
Let’s start with love and the design problem it solves for males. A male won’t get sexual access to a female unless the male can convince her that he’ll be around to share some of his resources with her and the kids he is going to produce. Since females have been selected for not being fooled by mere expressions of fidelity, they demand stronger assurances before they will allow males to have their way with them. As the Hollywood producer Samuel Goldwyn noted, a verbal contract is not worth the paper it is written on. A male’s promise is unenforceable. Females can’t rely on it because for a male it would be irrational to keep. With millions of sperm, the male’s best strategy is to promise, get sexual access, and renege. The mammalian female has only a few hundred eggs and a limited number of ovulatory cycles. She can’t afford to guess wrong about a reliable mate. What will reliably guarantee unenforceable promises about the future when it would be irrational for any male to keep them? One thing that would do it is a sign of irrational commitment to the female and to her interests that could not be faked.
Why must the sign signal irrational commitment? Because females recognize that it’s irrational of males to commit resources to one female. So the sign the male sends the female really has to be one of irrational commitment. Why must the sign be unfakable? Because a fakable sign of commitment is just that, fakable, and therefore not credible. Love is irrational and unfakable, by males at any rate. In nature’s search through design space for a strategy that will secure males’ sexual access, the emotion of love looks like it will just do the trick.
Irrational love does not fully solve the male’s design problems. After pairing up, the male faces another issue: the uncertainty of paternity. To convey resources to his mate’s offspring, he needs assurance that the kids are really his. This is an uncertainty problem females don’t have (unless kids get switched after birth). The male needs to reduce the uncertainty as much as possible. One way to do this is to pose a credible threat to anyone suspected of taking advantage of any absence from his partner’s bed. To make this threat credible, the male must be motivated to carry it out even when it is crazy to do so. And often it is crazy, since it’s the strong, the powerful, and the rich who usually try to take advantage of the weaker. The emotion of uncontrollable jealousy fits the bill perfectly. Revenge must be a credible threat; males must convince everyone that they will take measures to punish cheating wives and/or their lovers no matter how great the cost to themselves. Overpowering jealousy does the job, though it makes the occasional male actually sacrifice his own short-term and long-term interests. In the overall scheme, the fact that every male is prone to feel such emotions maintains a norm among men and women that effectively reduces the uncertainty of paternity and so enhances most males’ fitness. (Of course, female jealousy isn’t selected for reducing the uncertainty of maternity. There is little to reduce. But the emotion’s unfakable and irrational force deters