Abstract
Leibniz took pride in the Pre-established Harmony as an account of mind-body union. On the other hand, he sometimes claimed that he did not have a good account of such a union. I explain the tension by distinguishing between two importantly different issues that concern the union: body-soul interaction and the per se unity of the composite. Leibniz's positive evaluation concerns the issue of interaction rather than per se unity, R.M. Adams proposed that Leibniz did have the philosophical resources to account for a per se unity of the body-soul composite, in the form of Aristotelian scholastic solutions to that problem. I argue, by contrast, that Leibniz's notions of body and soul were too far removed from their scholastic predecessors for him to be able to deploy those resources in a compelling way.