In an article titled "Philosophy's Great Experiment," David Edmunds and Nigel Warburton (hosts of one of my favorite podcasts, Philosophy Bites) consider the recent rise in what has come to be known as "experimental philosophy" or "x-phi." Experimental philosophy is exactly as it sounds: a form of inquiry that makes at least partial use of quantitative research (i.e., measurable experiments) to answer philosophical questions. According to Edmunds and Warburton, there are three basic types of x-phi: (1) when philosophers use new brain-scanning technology to look for patterns in neural activity in subjects who are presented with philosophical problems, (2) when philosophers devise (social-science-ish) questionnaires and head out into the streets with a clipboard to interview people about their reasoning and intuitions, and (3) when philosophers go out and conduct "field" experiments, observing how people behave in certain situations, where that behavior may bear on philosophical speculations. If you're thinking that x-phi-(1) sounds awfully similar to regular old neuroscience, x-phi-(2) sounds like psychology, and x-phi-(3) sounds like sociology/anthropology... you're not alone.
Defenders of x-phi qua "philosophy proper" claim that it's long past time we put the kibosh on the dominant (Anglo-American) trend of armchair, unverified-intuition-driven, empirico-phobic speculation. Critics of x-phi respond that we're giving up the autonomy of philosophy as a unique domain of inquiry just to get our grubby paws on some of the scientists' (seemingly unlimited) research funding. There are, of course, merits to both sides of this debate. And neither side has the "history of philosophy" wholly on its side, either. Although there is a long tradition of philosophy as "pure" analysis or speculation, it's not always been that way. Descartes, Locke and Hume all performed their own philosophical "experiments," and there's no prima facie reason to dismiss the advantages of interdisciplinary work with natural and social scientists when we seem so comfortable working with all the products of historians, political theorists, artists, authors and the rest of the non-quantitative literati.
One of the truly booming areas of x-phi is in moral philosophy, partly a result of the explosion in "applied ethics" in the last half-century, but also led in part by American Philosophical Association Chair, Kwame Anthony Appiah (author of Experiments in Ethics). Moral philosophy is the home of many great "thought experiments": hypothetical situations involving some ethical conflict that are intended to aid in the articulation of moral reasoning and the formulation of moral norms. One of the most famous of these thought experiments is the "Trolley Problem." As everyone who teaches ethics knows, the Trolley Problem is eminently useful in drawing out the distinctions between different moral intuitions and models of moral reasoning (utilitarianism, deontology, virtue ethics, egoism, relativism, etc.). Now, neuroscientists and moral psychologists have jumped on the Trolley wagon, collecting extensive quantitative information on how people's minds and brains actually do think through the dilemma, sometimes in spite of what they may claim in terms of an ethical/philosophical position. And some x-philosophers are persuaded that the scientists' contributions to Trolley-ology are worth considering. What if your answer to the Trolley Problem, in fact, says less about your moral reasoning or moral norms than it does about the integrity of your prefrontal cortex, the obesity trends in your community, or whether or not you play too much Grand Theft Auto? What self-respecting philosopher could ignore those obviously relevant variables? And how can philosophers possibly know those variable without getting out of the office and going into the laboratory, or the streets, to measure them?
Edmunds and Warburton don't really come out in favor or against the merits of x-phi, though they do offer the following:
A philosophical problem is not an empirical problem, a fact is not an interpretation, an “is” is not an “ought,” a description of how we actually behave and think is not a rationale for how we should behave and think. Yet despite the critics, the clipboards and scanners are multiplying, with sometimes surprising effects on ancient debates.
I think it's absolutely critical that we don't lose sight of the meta-question here. We should keep asking "to what extent is x-phi 'philosophy'?" and "at what point does x-phi become a total derivative of the natural and social sciences with which it is collaborating?". Our discipline is notorious for its lead-footed slowness in keeping up with developments in other intellectual domains, which is probably why x-phi seems so strange to so many of us, and also why too many philosophers have chosen to bury their heads in the sand with regard to this obviously growing trend rather than to engage the very difficult question "what is philosophy?" again. But it cannot be ignored, and if philosophy wants to retain some kind of independent space in the liberal arts, it's going to have to carve out a proper space for x-phi.
It's here, it's queer, let's deal with it.