 But people, Korsgaard claims, are not just like chairs. (Actually, there’s a subplot in which she argues that chairs are more like people than you’d think, but here I’m going to leave it to one side.) Chairs don’t dissolve into their parts when they’re not seating anyone, whereas an agent constitutes itself by acting, or ceases to be an agent entirely. Imagine that Invasion of the Body Snatchers had it almost right: as in the film, pod creatures from outer space are eliminating us one by one, and replacing us with pod-grown impersonators; it is just that the films have gotten the size of the pods wrong. Instead of being as large as a person, each pod is roughly the size of a peapod, and so it takes a great many pod creatures working together to impersonate a single Earthling. (The illustration adapts the argument of Korsgaard 1996, ch. 13, to fit her later use of group agency as a model for individual agency.) If a colony of pod creatures is going to succeed in fooling the remaining Earthlings, it will have to behave as a single person, and to do that, the activities of the different pod creatures must be closely coordinated; after all, if the pod creatures making up the feet go off in one direction, and the pod creatures making up the torso go off in a different direction, no one will be fooled. When the pod creatures act together, and pull off the deception, they make themselves into a collective agent. (One mark of this is the first-person indexical, as when they whisper to each other, ‘We’re now going to go off to the left’; their coordination induces a point of view which is not that of any particular one of them.) That’s why action has to be generated by you-as-a-whole, rather than your psychic parts. 