it seems obvious to me that I have free will. When I have just made a decision, say, to go to a concert, I feel that I could have chosen to do something else. Yet many philosophers say this instinct is wrong. According to their view, free will is a figment of our imagination. No one has it or ever will. Rather our choices are either determined--necessary outcomes of the events that have happened in the past--or they are ­random.

Our intuitions about free will, however, challenge this nihilistic view. We could, of course, simply dismiss our intuitions as wrong. But psychology suggests that doing so would be premature: our hunches often track the truth pretty well [see “ The Powers and Perils of Intuition ,” by David G. Myers; Scientific American Mind , June/July 2007]. For example, if you do not know the answer to a question on a test, your first guess is more likely to be right. In both philosophy and science, we may feel there is something fishy about an argument or an experiment before we can identify exactly what the problem is.