Abstract
The paradox of coincidence, a paradox about the relation between a material object and its stuff, has been paid a great attention to in recent metaphysics. In this paper, I compare two influential approaches to this paradox; sortalism and fourdimensional worm theory, and defend sortalism. I give the following two arguments. (1) Worm theory, like sortalism, must introduce sortal concepts to resolve the paradox. So both approaches owe the (almost) same theoretical burden to explain how sortal concepts work. (2) Worm theory, unlike sortalism, introduces sortal concepts in a very problematic way.
