 Since the physical properties of different neural events are different, transitivity of identity prohibits claiming identity of mental properties with any of the physical properties whose instantiation realizes those mental properties. In a body of work stretching over many years, Jaegwon Kim (1993, 2005, e.g.) has argued that this division of mental from physical properties leads to exclusion of mental properties from playing a causal role. After all, it is widely accepted that the physical properties of neural events, together with a person’s state of neural connectivity, are sufficient to produce later neural events. Since behavior depends on muscle contractions that depend on neural innervation, it seems that physical events and structures, and the physical laws that apply to them, are quite enough to bring about our behavior. There is nothing left for mental properties to do.