This paper examines Aristotle’s account of the individuation of causal powers, which dominated much of scholastic thought about powers, and argues that John Buridan rejected it. It contends that Buridan criticizes Aristotle’s account on two counts. First, he attacks Aristotle’s view that we ought to individuate powers by appeal to their respective activities. Second, Buridan objects to Aristotle’s “single-track” account, which correlates one type of power with only one type of activity. Against this, it is argued, Buridan adopts a multi-track (...) approach, according to which a single power type may be correlated with many different types of activities. The paper claims that the basic idea of Buridan’s multi-track view is still defensible today, and can be viewed as a viable alternative to the contemporary single-track account of power individuation defended, for instance, by Jonathan Lowe. (shrink)