There is a small symposium in the New York Times today about the recent trend in analytic philosophy towards “experimental philosophy”:http://www.nytimes.com/roomfordebate/2010/8/19/x-phis-new-take-on-old-problems/unconvincing-results.

As some of the contributors note, it’s easy to overstate the trend that’s going on here. It’s not that for the 20th Century, philosophers used only armchair methods, and with the dawning of the 21st century they are going back to engaging with the sciences. When I was in grad school in the 90s, it was completely common to rely on psychological studies of all of uses, especially studies on dissociability, on developmental patterns, and on what was distinctive about people with autism or with “Capgras Syndrome”:en.wikipedia.org/wiki/Capgras_delusion. And the influence of Peter Singer on work in ethics meant that purely armchair work in ethics was out of the question, whatever one thought of Singer’s conclusions.

This was hardly a distinctive feature of philosophy in south-eastern Australia. Indeed, we were probably more armchair-focussed than contemporary American philosophers. As Ernie Sosa notes in the entry linked above, 20th century metaphysics is shot through with arguments from results in 20th century physics. The importance of objective chance to contemporary nomological theories is obviously related to the role of chance in different branches of physics and biology, and “modern theories of it”:http://plato.stanford.edu/entries/chance-randomness/ involve a lot of attention to various sciences. And I’ve lost count of the number of debates I’ve been in in philosophy of language where appeal has been made at one stage or other to cross-linguistic data, which is presumably not armchair evidence unless we assume that the person in the armchair knows every human language. So it’s a bit of a stretch to say, as Joshua Knobe does, that in that time “people began to feel that philosophy should be understood as a highly specialized technical field that could be separated off from the rest of the intellectual world.” I’m really not sure which of the great philosophers of the 20th century could be characterised this way. (Perhaps if you included mathematics in philosophy and not the “rest of the intellectual world” you can get a couple of great 20th century philosophers in. But I doubt it would get much beyond that.)

That’s not to say there’s nothing new that’s been happening in the last fifteen years or so. In fact I think there are three trends here that are worth noting.

One purely stylistic, and actually rather trivial, trend is that philosophers are now a bit more inclined to ‘show their workings’. So if I want to rely on “Daniel Gilbert’s”:http://www.wjh.harvard.edu/~dtg/gilbert.htm work on comprehension and belief, I’ll throw in a bunch of citations to his work, and to the secondary literature on it, in part to give people the impression that I know what’s going on here. You won’t see those kind of notes in, say, J. L. Austin’s work. But that’s not because Austin didn’t know much psychology. I suspect he knew much much more than me. But because of very different traditions about citation, and because of differences in self-confidence between Austin and me, his philosophy might look a bit further removed from empirical work.

A more interesting trend is picked up by Ernie Sosa – philosophers are doing a lot more experiments themselves than they were a generation ago. This is presumably a good thing, at least as long as they are good experiments!

The university that Ernie and I work at, Rutgers, has a significant causal role in this. We encourage PhD students to study in the cognitive science department while they are at Rutgers, and many of them end up working in or around experimental work. That’s not to say I’m at all responsible for this – I’m much more sedentary than my median colleague. But “many of my colleagues”:http://ruccs.rutgers.edu/ruccs/people_faculty.php have done a lot to encourage students interested in experimental work.

The third trend, and this one I’m less excited about, is the reliance on survey work in empirical work designed to have philosophical consequences. It seems to me that surveying people about what they think about hard philosophical questions is not a great guide to what is true, and isn’t even necessarily a good guide to what they think. We certainly wouldn’t take surveys about whether people think it should be legal for an Islamic community center to be built around the corner from “here”:http://www.kaffe1668.com/ to be significant to political theory debates about freedom of religion.

A slightly more interesting result comes from a survey that “Matthew Yglesias”:http://yglesias.thinkprogress.org/2010/08/things-people-believe/ posted this morning. If you trust “Gallup”:http://www.gallup.com/poll/16915/three-four-americans-believe-paranormal.aspx, only 26% of Americans believe in “the power of the mind to know the past and predict the future”. This is a more than a little nuts, at least as interpreted literally. I know that I had blueberries with breakfast, and I can confidently and reliably predict that the Greens will not win the Australian election currently underway. And I know these things in virtue of having a mind, and in virtue of how my mind works. There’s the power of the mind to know the past and predict the future in action!

Of course, the 74% of people who apparently denied that the mind has the power to know the past and predict the future probably don’t really deny that I have these powers. The survey they were asking was about paranormal phenomena generally. And I left off part of the question they were asked. It asked whether they believed in clairvoyance, which they ‘clarified’ as the power of the mind to know the past and predict the future. Presumably at least some of the people who answered ‘no’ (or ‘don’t know’) interpreted the question as not being about the power of the mind to know stuff through perception, memory and inference, but through some more extraordinary method.

It’s in general extremely hard to understand just what qustion people are answering in surveys. And this makes it hard to know how much significance we should place on different surveys. This matters to some live puzzles. For instance, as Jonathan Schaffer “recently wrote”:http://el-prod.baylor.edu/certain_doubts/?p=2019, there is an “emerging consensus in experimental philosophy, according to which … the magnitude of the stakes does not affect intuitions about knowledge.” (By ‘the stakes’ he means the stakes faced by a person about who we’re asking whether they know that p, when the person has to make a decision to which p is relevant.) This consensus is largely because the experimenters asked subjects whether certain fictional characters, some facing trivial decisions and some facing quite momentous decisions, knew that p, where p is something that would be important in their deliberations. Generally, they didn’t find a difference in the responses.

But there is quite a bit of evidence, including “a lot of experimental evidence”:http://www.erin.utoronto.ca/~jnagel/Knowledge&Stakes.pdf (PDF), that differences in stakes in this sense really do matter to cognitive states. In particular, what it takes to have settled the question to one’s own satisfaction of whether p is true, depends on what is at stake, and if you ask them the right way, survey respondents agree that it depends on what is at stake. Assuming, as everyone in this debate does, that knowledge requires settling questions to one’s own satisfaction, this means we have empirical evidence that stakes matter to knowledge. What does this mean for the consensus that Schaffer reports? I suspect it means, like in the Gallup survey, that different people are interpreting the survey questions differently, but there are lots of alternative explanations. In any case, I’d want a lot more evidence than surveys though before I overturned a well established result in experimental psychology.