Abstract

Contemporary metaphysics, and especially neo‐Aristotelian metaphysics, tackles many of the same problems as Avicenna did. One of these problems is the possibility of substantial kind change. For instance, is it possible for an animal to change its species? Aristotle and Avicenna both regarded species to be eternal, but their metaphysics might allow for individuals to change their kinds—what is important is that one kind cannot change into another kind. From a contemporary perspective, this may seem odd, given what we know about the evolution of species. Moreover, phenomena like beta decay seem to suggest that a given sample of an element may change into another element, so one might think that contemporary science allows both changing kinds and substantial kind change. Yet, I suggest that the essentialist metaphysics that has developed from Aristotle to neo‐Aristotelian metaphysics, via Avicenna, may already possess the necessary tools to accommodate all this.