What is the difference between a wink and a blink? The answer is important not only to philosophers of mind, for significant moral and legal consequences rest on the distinction between voluntary and involuntary behavior. However, "action theory" -- the branch of philosophy that has traditionally articulated the boundaries between action and non-action, and between voluntary and involuntary behavior -- has been unable to account for the difference.

Alicia Juarrero argues that a mistaken, 350-year-old model of cause and explanation -- one that takes all causes to be of the push-pull,...