Sunday, February 26, 2012

Lunch Chat (3/1): Thought Experiments

Breaking Philosophical News!: Famous Philosopher Faked Results of Thought Experiments!

So reports the new, hilarious Philosophy "News" Blog, FauxPhilNews — a sort of philosophical analog of The Onion. The parody got me thinking, though: how important are thought experiments to philosophy? — or to science, for that matter? How, exactly, do they differ from mere intuitions?

In a way, this picks up on the game, . . . er, discussion from last week about counterfactual conditionals: we often decide what to do based on thinking about how things would go if we acted in a different way. I decide not to give in to my craving for a third slice of pizza because I know that if I did, I'd feel sick. Perhaps something similar goes on when physicists use thought experiments. One famous example is Einstein's "Elevator" thought experiment. Here's the best video I can find on it (though there must be better ones — anyone?):



But the worry here is pretty obvious: if we find that in reasoning about certain counterfactuals absurd (as in the "Big Bang Theory" game), how can we be assured that thought experiments won't lead us astray? Brown and Fehige summarize this worry nicely in their article on thought experiments in the Stanford Encyclopedia of Philosophy:

How can we learn about reality (if we can at all), just by thinking? More precisely, are there thought experiments that enable us to acquire new knowledge about the intended realm of investigation without new data? If so, where does the new information come from if not from direct contact with the realm of investigation under consideration? Finally, how can we distinguish good from bad instances of such thought experiments? These questions seem urgent with respect to scientific thought experiments because most philosophers and historians of science “recognize them as an occasionally potent tool for increasing man's understanding of nature. […] Historically their role is very close to the double one played by actual laboratory experiments and observations. First, thought experiments can disclose nature's failure to conform to a previously held set of expectations. In addition, they can suggest particular ways in which both expectation and theory must henceforth be revised.” (Kuhn, 1977, p. 241 and 261) The questions are urgent regarding philosophical thought experiments because they play an important role in philosophical discourse. Philosophy without thought experiments seems unthinkable (see e.g., Myers, 1968).
So that's what I'd like to talk about on Thursday over pizza. Hope to see you there!