What are physical objects like when they are considered independently of their causal interactions? Many think that the answer to this question involves categorical properties- properties that make contributions to their bearers that are independent of any causal interactions those objects may enter into. In this paper, I examine two challenges that this solution poses to Physicalism. The first challenge is that, given that they are distinct from any of the scientifically described causal powers that they happen to convey, categorical properties will not qualify as being 'physical' properties. Given the right definition of 'physical', this challenge can be overcome. I argue, however, that the only way we can have a positive grasp of the nature of categorical properties is via 'acquaintance'- a non-physical relation. This second challenge to Physicalism cannot be overcome.