Anscombe and the difference rationality makes

Anscombe famously argues that to act intentionally is to act under a description , and that ‘it is the agent’s knowledge of what he is doing that gives the descriptions under which what is going on is the execution of an intention’. Further, she takes ‘knows’ to mean that the agent can give these descriptions herself. It would seem to follow that animals cannot act intentionally. However, she denies this, insisting that although animals cannot express intentions, they can have them. But how can we speak without equivocation of humans and animals acting intentionally while maintaining that linguistic expressibility is an essential characteristic of only human action? I argue that whereas animal intentions are immanent in their behavior, human action is an actualization of a capacity to make judgments about what is to be done and that this confers on human intentions the kind of independence from behavior.