In the opening pages of Plato's Republic, Cephalus suggests that what justice requires is speaking the truth and paying one's debts. But Socrates immediately offers a thought experiment to show that Cephalus's account of justice is not correct:

When Cephalus agrees, Socrates concludes that “speaking the truth and paying your debts” is not an adequate account of justice.

Philosophy has changed in many ways in the 2,400 years since Plato wrote the Republic, but the method Plato uses in this passage is still one of the most basic tools in the philosopher's toolkit. Although there is some debate about how, exactly, the method should be characterized, the basic outlines are clear enough. A philosopher describes a real, or more often an imaginary, situation and asks his audience whether the people or objects or events described have some philosophically important property or relation: Is the agent's action unjust? Was it morally wrong to push the large man off the footbridge to stop a trolley that would otherwise kill five people? (Thomson Reference Thomson1976) Does the person who holds a ticket in a lottery where the odds are one in a thousand know that the ticket won't win? (Kyburg Reference Kyburg1961, p. 197; see also Hawthorne Reference Hawthorne2004). Does the “Chinese Room” understand the story? (Searle Reference Searle1980) When things go well (as they always did in Plato's dialogues!), the audience will agree that the answer is intuitively obvious, and the philosopher will conclude that the content of these intuitive judgments is probably true. If it is intuitively obvious that it is wrong to push the man off the footbridge, and that is what the philosopher's theory entails, then this counts as evidence for his theory. If it is intuitively obvious that the Chinese Room does not understand the story or have other intentional states, but a philosopher's theory entails that it does, this counts as evidence against his theory.

The overwhelming majority of philosophers who use this method are WEIRD. Moreover, as reflected in my choice of pronouns, the majority of those who teach in North American and European philosophy departments are male. And, of course, on at least one dimension, professional philosophers are extreme outliers among WEIRD people, as most of them have undergone five or more years of training and vetting in one of the 30 or 40 leading graduate programs. About a decade ago, as we became acquainted with the emerging literature reviewed by Henrich et al., my colleagues and I began to wonder whether these WEIRD philosophers might have weird philosophical intuitions – intuitions that differed from those of people who did not share their cultural and educational background. To find out, we did something philosophers often do – we scoured the literature. We also did something that philosophers rarely do: We designed and ran our own experiments aimed at finding out whether people who were not WEIRD shared the intuitions that play such a central role in Western philosophy.

Although this work is still in its infancy, I think it has begun to provide an important addendum to Henrich et al.'s survey suggesting that, in a number of areas of philosophy, the intuitions of philosophically trained, WEIRD males are indeed quite different from the intuitions of people in other cultural groups. Space does not permit an exhaustive discussion of the literature, but here are some of the highpoints.