Some authors have argued that, in order to give an account of weakness of the will, we must assume that the mind is divisible into parts. This claim is often referred to as the partitioning claim. There appear to be two main arguments for this claim. While the first is conceptual and claims that the notion of divisibility is entailed by the notion of non-rational mental causation (which is held to be a necessary condition of weakness of the will), the (...) second is explanatory and claims that the notion of divisibility is required for the causal explanation of weak-willed action. In this paper I want to argue that the partitioning claim remains unsupported, no matter how it is interpreted, and that weakness of the will can be made perfectly good sense of without the idea that the mind is divisible into parts. In fact, there are available various explanatory models each of which characterizes different psychological mechanisms that may be involved in weakness of will, none of which depends on any claims about mental division. I describe three familiar mechanisms and argue that weakness of will may occur as the result of any one of them. (shrink)