<p>The antonyms “occurrent” and “standing” are used in philosophy of mind to distinguish two types of mental state, but the terms have been interpreted in various conflicting ways. I argue for what I consider the most theoretically useful interpretation: occurrent states are functionally engaged, whereas standing states are not. In brief, a functionally engaged mental state is one that is causally interacting with other mental states and/or subpersonal input or output states. My account thus defines a mental state’s occurrency as a type of external activity. In contrast, Gary Bartlett (2018) construes occurrency as internal activity (i.e., processiveness) that consists of salient fluctuations in the state’s neural properties. I contend that defining occurrent states as functionally engaged as opposed to processive has two advantages: (1) rendering those states functionally analyzable, via the notion of an enacted functional role; and (2) affording occurrent states psychological significance, namely, constituting mental activity as opposed to mental makeup.</p>