Evolution Doesn’t Select for Ethics

Evolution Doesn’t Select for Ethics February 29, 2012

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The second most incorrect thing people say about evolution is that it is the survival of the fittest.  (The most incorrect award has to go to the claim it doesn’t exist).  The problem with this framing is that it sets up a picture of evolution-as-craftsman, carefully scrutinizing genetic variations and selecting and nurturing the most promising variant.

But evolution isn’t selecting for, it’s selecting against.  Instead of survival of the fittest, it’s the persistence of the just barely workable.  If an organ or a social structure is stable, it has the potential to last.  Put simple, evolution favors local maxima.

If you want to get to the higher peak, you need something more directed than evolution or some pretty brutal selection pressures.  So even if we believed that evolution was favoring moral improvement, it would be easy for progress to come to a halt far short of its potential.

But it’s worse than that.  The z-axis in the graph above isn’t ‘goodness of group dynamics’ or ‘considerate feelings for others.’  It’s simply successful reproduction.  Evolutionary psychologists can come up with elaborate explanations of how altruism could be part of a local maxima (or a Nash equilibrium, if we’re talking game theory), but that’s a long way from claiming it’s a necessary property of all local maxes or just the global max.

It’s easy to find counterexamples of stable evolutionary strategies that strike us as morally abhorrent.  This one comes from Science as excerpted by TYWKIWDBI, and concerns gelada baboons:

If a newcomer ousts the chief monkey, it’s bad news for the group’s females. A wave of death sweeps through the unit, as the new male kills all the youngsters whom his predecessor fathered… But that’s not all. Eila Roberts from the University of Michigan has found that the new male’s arrival triggers a wave of spontaneous abortions. Within weeks, the vast majority of the local females terminate their pregnancies. It’s the first time that this strategy has been observed in the wild…

It’s obvious why the incoming males kill any existing infants. Female geladas don’t become fertile until they stop raising their existing children. Assuming no abortions, they go for three years between pregnancies. That’s longer than the typical reign of a dominant male. So, a newcomer, having finally won the right to mate, has few opportunities to actually do so. To make things worse, his females are busy raising someone else’s children. His solution: kill the babies. The quicker he does this, the sooner the females become fertile again, and the sooner he can father his own children.

But why would a pregnant female abort her own foetus? Roberts thinks that it’s an adaptive tactic in the face of a new male’s murderous tendencies. Since the male would probably kill the newborn baby anyway, it’s less costly for the female to abort than to waste time and energy on bringing a doomed infant to term. Her future offspring, conceived more quickly and fathered by the incumbent king of the hill, will stand a better chance of survival.

It’s stable states like these that mean I have little patience for evolutionary psychology or some spins on natural law as a foundation for ethics and obligation.  Evolution is a wholly amoral process, so why would I expect that it would preserve and amplify whatever signal points us to the Good and the True?

Some atheists seem to think evolutionary psychology will excuse us from thinking about metaphysics, and some natural law proponents think that by studying our own physical bodies, we can intuit their form and proper function.  I’d love to hear commenters on either side explain how they can distill moral instruction from a blind process that can’t take ethics into account.

The one counterargument I want to dispatch in this post is the idea that evolution promotes moral behavior because it has given us an intelligence to recognize moral behavior and to modify ourselves appropriately.  This is just saying that evolution has brought us to the point where we can actively and deliberately subvert evolution.  This is true, and I’m glad to welcome you to the transhumanist club, but it does not suggest evolution is directed towards moral behavior or reflection.

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  • anodognosic

    Leah, when you talk about us evolving to be able to recognize moral behavior, what is your metaethics here? That is, what kind of independent ethical system could a blind, amoral process bring us to recognize? I have trouble coming to any answer but a largely species-relative one, because it seems to me that terminal values are largely contingent on evolution. If evolution might have easily landed us at a different local maximum (about which I agree with you), doesn’t that create a problem for moral realism? To me, that provides a serious difficulty to truly universal objective morality. Personally, I’m more or less comfortable accepting a certain humanist chauvinism that says that yes, things might have been otherwise if we had evolved differently, and our morality radically different, but I am still going to call (terminal) human values “right”. How do you square moral realism with this objection?

  • I’m curious as to what basis for morality you’re drawing from. If it doesn’t take into account the operations of nature, isn’t it just arbitrary?

  • Mat

    “But evolution isn’t selecting for, it’s selecting against.”

    How can you do one without doing the other?

    • anodognosic

      Don’t get too bogged down in semantics. The takeaway point is that evolution doesn’t select the best of the best, it just tends to remove the not-good-enough to survive and reproduce.

    • keddaw

      As a simple example, imagine you have a gene where if you have no copy you get two limbs, one copy will give you three and two copies means you have four. Three limbs may restrict movement whereas two or four can be compensated for so predators would naturally kill off those with 3 limbs. Over time you’d be left with a population of 2 and 4 limbed animals with few/no 3 limbed ones. Nature isn’t selecting for more, or fewer, limbs, simply against 3 limbs.

      • Jonathan

        But it’s easy to come up with equally valid situations where you can describe “selection for”. It’s a pointless distinction to make.

      • Mat

        I see what you are saying, but isn’t it easier to think in terms of “selecting for” when considering how sexual selection gives rise to traits like large antlers on deer? Certainly you can say that “antlers that are not large enough are being selected against” but it seems more natural to say that larger and larger antlers are being “selected for” and to think of the selective pressure as driving change in a very specific direction.

        • Alex

          Do you really want to have a pointless semantics debate? I can’t think of any other reason for quibbling over arbitrary word choice. The point being made is this. Natural selection does not look for the absolute best possible traits in an organism and then make sure that populations gradually move towards that ideal, rather it weeds out organisms that don’t make the cut.

        • keddaw

          I defer to Leah’s more comprehensive post, but I’d just like to point out there is a phenomenally large difference between sexual selection and natural/ecological selection. Sexual selection can easily get caught in a loop that is ultimately a genetic dead end, whereas natural selection has a feedback loop that keeps modifications beneficial for both survival AND reproduction.

      • leahlibresco

        Jonathan, Mat, and Alex, I’ve just written a new post trying to address the objections you’re raising: Evolution isn’t on Our Side.

  • When proponents of natural law talk about deriving moral rules from observations of biology, two things should be kept in mind: 1) they don’t mean that all, or even most, moral rules have any biological grounding, and 2) they have no interest in the evolutionary of biological facts.

    Most Christians would agree with you Leah, that the evolution of species doesn’t aim at morality. (Well, a Catholic might insist that evolution is under divine direction, but this would be in the same way that the atheist-making earthquake in Lisbon was under divine direction, and would not be a complacent retreat to faith but an invitation to wrestle with the idea of providence — which here is not our subject.)

    What natural lawyers care about is not the evolutionary origin of biological features, or whether or not animals exhibit homologous behaviors to those under discussion. Their inquiry is after the conditions that allow for human flourishing, and inasmuch as humans are biological objects (if you insist, Leah, I’ll add “at least for now”), biological facts about humanity are not irrelevant when we think about what sort of state counts as flourishing.

    Even a natural lawyer would agree, however, that this is inadequate to give rise to what we might call “social morality.” The examples of moral attitudes that you give (“goodness of group dynamics,” “considerate feelings for others”) might sometimes be motivated by self-interest, but don’t have any necessary link to the physical flourishing of a human organism. Here a natural lawyer would abstract from individual people, and think about what conditions lead to the flourishing of a community — and at this point biological concerns are largely irrelevant.

    Additionally: even Catholic natural lawyers (I mean the real ones, not the dime-store kind that you tend to run into online) are aware that it is very difficult to derive exceptionless moral norms from considerations of physical (or social) flourishing alone. Drugs, for example, tend not to conduce to human flourishing, and there are lots of examples of people that have been wrecked by drugs. At the same time, though, it’s not like everyone who experiments in college continues through life as a maimed organism. Similarly, a Catholic might agree with Santorum that contraception has wrought serious social harms, while acknowledging that lots of people use condoms without ruining the lives of their children.

    To make the move from correlations that suggest things to avoid, to blanket prohibitions, something more than observation of nature is necessary. Modern Catholics tend to use “divine command” to make this leap; traditionally it was done through the highly-developed Catholic theory of the common good. But in either case some additional logical step has to be taken.

    • anodognosic

      This seems like a vacuous conception of natural law–just dressed-up rule utilitarianism with divine command tacked on to give it the proper gravitas.

      • Oh, it’s much richer than that. I only meant to bring up the role biology as such plays in Catholic moral thought: which is indeed a minor role, and which could in itself serve as the basis only of a somewhat “vacuous” moral code.

        The foundations of Catholic ethics — vacuous or otherwise — lie elsewhere. But this is to get into territory that is contested even among Catholics, and has been for centuries, whereas (among literate Catholics at least) there’s a fairly consistent way of thinking about the moral value of biological data.

  • Lukas

    “We talk of wild animals but man is the only wild animal. It is man that has broken out. All other animals are tame animals; following the rugged respectability of the tribe or type.”
    ― G.K. Chesterton

    You wrote, “some natural law proponents think that by studying our own physical bodies, we can intuit their form and proper function.”
    Bulimia is a moral/psychological disease. One of the signs that it is a disease is that it thwarts that natural digestive function in a way that it is harmful to the person’s health. Agree or disagree?
    Of course not all things which are “unnatural” are immoral – the tongue is designed for eating and speaking, but it can used to lick postage stamps. The capacity for artifice is a part of human nature.

  • butterfly5906

    “Evolutionary psychologists can come up with elaborate explanations of how altruism could be part of a local maxima (or a Nash equilibrium, if we’re talking game theory), but that’s a long way from claiming it’s a necessary property of all local maxes or just the global max.”

    I’m no fan of evolutionary psychology, but I just wanted to point out that they don’t have to claim that altruism is part of every local or global maximum, just that it is a part of the one we’re on.