Skip to content

Podcast brief

Is Human Altruism Real, or Just Evolved Hypocrisy?

Barry Lam questions evolutionary psychologist Michael McCullough and philosopher Kieran Setiya about whether a kidney donated to a stranger can be explained by evolution at all.

A Stoa brief of an episode from Hi-Phi Nation

The Selfless Kidney Donor

With Michael McCullough, Penny Lane, and Kieran Setiya Published 41 min

Listen to the original episode

The episode belongs to its makers. This page summarizes its arguments in Stoa's words and points to the moments where they are made. Brief updated .

The brief

The conversation asks whether an act like donating a kidney to a stranger, with no benefit to the donor, can be explained by evolution, or whether it shows evolutionary explanations of human morality are missing something. Host Barry Lam uses the real case of a filmmaker who gave a kidney to someone she never met to press evolutionary psychologist Michael McCullough on this question, then calls in philosopher Kieran Setiya to test the answer.

McCullough's case starts with a contrast: vampire bats share blood with unrelated bats, but only because sharing tracks reciprocity, the bats that get fed are the ones who fed others before. Human strangers-helping-strangers, by contrast, cannot be explained by kin selection or by reciprocity, since the recipient can never repay the favor. McCullough argues that human reasoning, itself a naturally selected capacity, went on to discover an impartial moral code, one that treats comparable sacrifice as obligatory regardless of relationship or distance. He extends this to claim that societies built on this kind of generosity, meeting basic needs and extending concern to strangers, will outcompete narrower, nepotistic ones.

Lam is not convinced. He points out that altruistic kidney donors are vanishingly rare, and that most people, confronted with the same choice, reach for reasons not to act. If almost no one does it, he asks, what exactly is evolution supposed to be explaining. Setiya sharpens the objection by splitting the question in two: explaining why humans value and praise altruism in others is easy on a broadly Humean view, since it pays to associate with generous people, but explaining why humans are motivated to be altruistic themselves is a much harder problem, one that rare cases like kidney donation do little to settle.

The disagreement is not resolved so much as relocated. Lam ends up conceding Setiya's distinction: humans may genuinely value altruism without being moved to practice it, a pattern he calls evolved hypocrisy rather than selfishness. Setiya's parting note is a qualified openness that this gap between what we praise and what we do need not be permanent. The question worth sitting with is which side of that gap describes your own last opportunity to help.

Strongest arguments

Vampire bats show reciprocity, not true altruism

1:04

Vampire bats share blood with non-relatives, which initially seems evolutionarily puzzling. Researchers find the best predictor of sharing is whether the recipient had previously reciprocated, showing that even seemingly selfless animal behavior tracks self-interest through exchange, which sets up the contrast with human cases.

McCullough argues a new impartial moral code has emerged in humans

9:58

Michael McCullough argues that altruistic kidney donation and modern welfare states cannot be explained by kin selection or reciprocity, since donors help strangers who can never repay them. He proposes that human reasoning ability, itself a product of natural selection, produced a distinctively human, impartial moral code exemplified by principles like comparable sacrifice.

Reasoning itself is a naturally selected adaptation that discovers moral truths

18:22

McCullough claims humans evolved superior reasoning to solve practical problems like tracking prey or weather, and that this same capacity later discovered genuine ethical insights, such as universal human dignity. He treats this as a two-step story: selection for better reasoning first, then that reasoning uncovering impartial moral truths.

McCullough predicts altruistic societies outcompete selfish ones

21:22

Pressed by Lam on whether his view makes a testable prediction, McCullough argues that societies which meet everyone's basic needs and extend concern to strangers are more commercially and even militarily competitive than nepotistic, purely reciprocal societies. He rejects the intuition that keeping workers needy motivates harder work.

Lam argues altruism is rare and people rationalize refusing to donate

26:19

Barry Lam observes that altruistic kidney donors are statistical outliers, comparable to the tiny share of GDP given as foreign aid, and that ordinary people confronted with the filmmaker's example generate rationalizations for why they personally cannot donate. He concludes this looks like rationalizing rather than genuine moral reasoning, and that there may be no general human trait of altruism for evolution to explain.

Setiya distinguishes altruistic motivation from altruistic values

33:29

Kieran Setiya proposes separating the evolution of altruistic motivation from the evolution of altruistic values, arguing the latter is much easier to explain. On a Humean, spectatorial view of ethics, moral judgment functions to identify who is good to associate with, so praising altruism in others is self-interested even if one is not personally motivated to act altruistically.

Lam concludes humans evolved to be hypocrites

36:51

Building on Setiya's distinction, Lam concludes that humans evolved to value and praise altruism in others, so as to benefit from associating with altruistic people, while not being motivated to be altruistic themselves. He frames hypocrisy, not selfishness or selflessness, as the trait best explained by evolution.

Disagreements

Whether evolution explains rare altruistic behavior

29:21

Michael McCullough argues that a distinctively human, evolved capacity for impartial moral reasoning explains altruistic acts like kidney donation and the welfare state. Barry Lam and Kieran Setiya are both skeptical that an evolutionary fitness explanation can account for behavior this rare, calling it an outlier phenomenon rather than a general trait to be explained.

Whether humans are altruistic or merely value altruism

32:38

Barry Lam initially assumes there is no meaningful difference between humans knowing altruism is right and humans actually being altruistic, concluding humans are not altruistic in either sense. Kieran Setiya pushes back, arguing humans likely do have genuine altruistic values even though they largely lack altruistic motivation, a distinction Lam comes to accept as less cynical but still pessimistic.

Concepts discussed

  • altruism Behavior that benefits another at a cost to oneself, with no expectation of return.
  • evolution The process by which heritable traits become more or less common in a population due to differential survival and reproduction.
  • comparable sacrifice A moral principle stating that one must prevent a very bad outcome for another if doing so does not require sacrificing something of similar significance.
  • moral reasoning The cognitive process by which a person works out what is morally required or permissible in a situation.
  • reciprocal altruism An evolutionary strategy in which organisms help others who are likely to help them back in the future.
  • impartial morality The ethical view that moral consideration should not depend on kinship, community membership, or the possibility of reciprocation.
  • kin selection The evolutionary theory that organisms are more likely to help genetic relatives because doing so still propagates shared genes.
  • moral judgment The act of evaluating actions, character, or people as good, bad, right, or wrong.

Philosophers and works discussed

  • Michael McCullough
  • Kieran Setiya
  • The Kindness of Strangers: How a Selfish Ape Invented a New Moral Code By Michael McCullough.

Questions this episode answers

  • Why do vampire bats share blood with unrelated bats?

    2:45

    Vampire bats regurgitate blood to hungry roost mates, and researchers found the best predictor of who gets fed is whether that individual had previously fed the helper, showing the behavior tracks reciprocity rather than pure altruism.

  • Can evolution explain why some humans donate kidneys to strangers?

    9:58

    Michael McCullough argues that human reasoning, itself naturally selected, generated an impartial moral code that explains altruistic kidney donation, since it cannot be explained by kin selection or reciprocity. Barry Lam and Kieran Setiya are skeptical, noting that such donation is a rare outlier behavior, which makes it a poor fit for a general evolutionary explanation.

  • What is the principle of comparable sacrifice in ethics?

    12:07

    The principle holds that if you can prevent something very bad from happening without sacrificing something of comparable significance, you are obligated to do it, regardless of your relationship to the person harmed or their distance from you. It is used to explain both everyday duties, like calling for help in an emergency, and radical acts like donating a kidney to a stranger.

  • What is the difference between altruistic motivation and altruistic values?

    33:29

    Kieran Setiya distinguishes explaining why humans are motivated to act altruistically from explaining why humans value and praise altruism in others. He argues the latter is easier to explain evolutionarily, since praising and associating with altruistic people benefits you even if you are not motivated to make sacrifices for strangers yourself.

  • Does a Humean view of ethics explain why we praise altruism in others?

    34:00

    Setiya describes a broadly Humean, spectatorial view where the point of ethical judgment is to evaluate who is good to associate with, rather than to guide one's own action. On this view, praising altruistic people is self-interested because it helps identify good associates, making the evolution of altruistic values less mysterious than the evolution of altruistic motivation.

  • Are humans naturally selfish, altruistic, or something else according to evolutionary theory?

    36:51

    The conversation concludes that humans may have evolved to value and praise altruism in others without being motivated to act altruistically themselves, a trait the host calls hypocrisy rather than selfishness or selflessness. Kieran Setiya adds that human motivational nature is historically changeable, so this incongruence between values and behavior could shift over time.

Sources

  1. Hi-Phi Nation, The Selfless Kidney Donor Podcast episode, original episode