On Good and Bad Reasons for Endorsing Mereological Hylemorphism

Hylemorphism is the view that an object’s essence is—at least in part—determined by what is called the object’s form. According to the mereological version of hylemorphism, an object’s form is also a proper part of the object alongside its physical parts. Whether there are good reasons for this assumption depends not least on the background assumptions about forms and their role in the composition of objects. In the case of contemporary mereological hylemorphists, this background is provided by what I call vertical hylemorphism. I shall first argue that, as long as vertical hylemorphism is accepted, there are no good reasons for endorsing mereologism. Then, I shall point out that there is an attractive, alternative version of hylemorphism—horizontal hylemorphism—which provides good reasons to endorse mereologism.