An encyclopedia entry which covers various revisionary conceptions of which macroscopic objects there are, and the puzzles and arguments that motivate these conceptions: sorites arguments, the argument from vagueness, the puzzles of material constitution, arguments against indeterminate identity, arguments from arbitrariness, debunking arguments, the overdetermination argument, and the problem of the many.

Revisionary ontologies seem to go against our common sense convictions about which material objects exist. These views face the so-called Problem of Reasonableness: they have to explain why reasonable people don’t seem to accept the true ontology. Most approaches to this problem treat the mismatch between the ontological truth and ordinary belief as superficial or not even real. By contrast, I propose what I call the “uncompromising solution”. First, I argue that our beliefs about material objects were influenced by evolutionary (...) forces that were independent of the ontological truth. Second, I draw an analogy between the Problem of Reasonableness and the New Evil Demon Problem and argue that the revisionary ontologist can always find a positive epistemic status to characterize ordinary people’s beliefs about material objects. Finally, I address the worry that the evolutionary component of my story also threatens to undermine the best arguments for revisionary ontologies. (shrink)

An overview of contemporary part-whole theories, with reference to both their axiomatic developments and their philosophical underpinnings.