In recent philosophical work on attention, several authors have employed versions of an argument purporting to show that attention is not identical to any cognitive process. Others have criticised this argument. The present article addresses their various criticisms, and shows the original argument to be a valid one. It also shows that this argument cannot be resisted by taking attention to be a disjunction of several processes, by taking it be a genus of process that is composed of various species, (...) nor by taking it to be a process-determinable, for which particular cognitive processes are determinates. The metaphysical position that most readily accommodates this argument’s conclusion is a version of adverbialism. It should be understood as making a claim about the essence of attention. Some of the confusions in this area are shown to originate in the difficulty of glossing such a claim in modal terms. (shrink)