 It is usual to note that etiological (teleological) functions are distinct from the causal-role functions involved in what is standardly called “functionalism” in philosophy of mind. Causal-role functions are often defined as a select subset of a trait’s actual causal dispositions, and functionalism is often defined as the view that mental states are individuated or classified into types on the basis of such dispositions (see, e.g., Block 1986). If causal-role functions are a subset of dispositions actually possessed by token traits then they do not permit the possibility of an important kind of malfunctioning because a trait cannot have the causal-role function to Z and at the same time lack the disposition to Z.