A Darwinian Genealogy of Morals
A Darwinian Genealogy of Morals
According to the Darwinian account, given the contingencies of the evolutionary landscape—i.e., the circumstances of survival—certain behaviors are adaptive; and so, any propensity for such behaviors will also be adaptive. Such explains the flight instinct in the pronghorn, the spawning instinct in the cutthroat salmon, and my instinctual aversion to insulting Harley riders in biker bars. Insofar as such propensities are genetic (at least the first two examples would seem to qualify here), they are heritable and thus likely to be passed down to offspring.
Imagine, for example, a time in the early history of hominids when the circumstances of survival prompted an early patriot (and kite-flying inventor perhaps) to advise, “We must all hang together, or assuredly we shall all be torn apart by ravenous wolves.” Insofar as such cooperation depends on heritable dispositions of group members, those dispositions will confer fitness.
Darwin speaks of “social instincts” that are at the root of our moral behavior. These include a desire for the approbation of our fellow humans and a fear of censure. They also include a general sympathy for others. He explains:
In however complex a manner this feeling may have originated, as it is one of high importance to all those animals which aid and defend one another, it will have been increased through natural selection; for those communities which included the greatest number of the most sympathetic members, would flourish best, and rear the greatest number of offspring.1
A favored “complex manner” of the origin of such feelings involves an appeal to two varieties of altruism: kin altruism is directed at family members, chiefly one's offspring; and reciprocal altruism is directed at nonfamily members and even to strangers. The former is an other-regarding attitude and behavior, particularly concerning one's own children but extending in descending degrees to other family members, that does not seek any returns. The advantage, of course, is in the reproductive success. The sense of parental duty that is possessed by, say, a female sea turtle ensures only that she lay her eggs somewhere above the high tide mark. From there her relatively self-sufficient offspring are on their own against daunting odds—something like a 1 in 10,000 chance of reaching maturity. Those odds are offset by the sheer numbers of hatchlings so that a fraction manage to survive the elements and elude myriads of predators.
Such a numbers strategy would hardly work for the human species, given the utter helplessness of the human infant. Babies tend to suffer an inelegant fate if left untended. The probability that a human infant will die if left to his own resources at, say, just above the high tide mark, is a perfect 1. And those same odds would prevail for each of 10,000 similarly abandoned babies. (Word would spread quickly in the wild: “Hey, free babies!”) Human parents possessed of no more parental instinct than sea turtles would find that their line came to an abrupt end. Thus, a strong sense of love and concern is adaptive and heritable and has the same function, a means to reproductive success, among humans that hatchling self-sufficiency and sheer numbers have among turtles.
Reciprocal altruism, on the other hand, is rooted in a tit-for-tat arrangement that ultimately confers greater reproductive fitness on all parties involved. Consider, for instance, the symbiotic relationship that exists between grouper and cleaner shrimp. Though the shrimp would certainly make a nice snack for a hungry grouper when it is busily flossing the fish's teeth from the inside, the benefit of long-term hygiene (Whiter teeth! Fresher breath!) outweighs that of short-term nourishment, and so the fish is programmed to pass on the prawn. The shrimp, of course, benefits from a delectable meal of the gunk otherwise responsible for halitosis in grouper.
Similarly, there is benefit to be gained from cooperative and altruistic behavior among humans. For example, Darwin observes “A tribe including many members who, from possessing in a high degree the spirit of patriotism, fidelity, obedience, courage, and sympathy, were always ready to aid one another, and to sacrifice themselves for the common good, would be victorious over most other tribes; and this would be natural selection.”2 And membership in such a victorious tribe has its advantages. To attempt a metaphor, when a baseball team functions like a well-oiled machine, say, with a Tinker, Evers, and Chance infield, the likelihood that all of the members will sport World Series rings is increased.
Thus, the human moral sense, conscience, is rooted in a set of social instincts that were adaptive given the contingencies of the evolutionary landscape. Of course, there is more to the moral sense than the instincts Darwin had in mind. All social animals are possessed of such instincts, but not all are plausibly thought of as moral agents.3 According to Darwin, conscience emerges out of a sort of “recipe.” It is the result of the social instincts being overlaid with a certain degree of rationality. He writes:
The following proposition seems to me in a high degree probable—namely, that any animal whatever, endowed with well-marked social instincts, the parental and filial affections being here included, would inevitably acquire a moral sense or conscience, as soon as its intellectual powers had become as well, or nearly as well developed, as in man.4
Wolves in a pack know their place in the social hierarchy. A lower ranked wolf feels compelled to give way to the alpha male. Were he endowed with the intellectual powers that Darwin had in mind, then, presumably his “moral sense” would tell him that obeisance is his moral duty. He would regard it as a moral fact that, like it or not, alpha interests trump beta or omega interests. And our grouper, if graced with rational and moral autonomy, might reason, “It would be wicked of me to bite down on my little buddy here after all he has done for me!”
Of course, such a “recipe” is precisely what we find in the human species, according to Darwin. We experience a strong prereflective pull in the direction of certain behaviors such as the care for our children or the returning of kindness for kindness; and, on reflection, we conclude that these are our moral duties.