Purposive action is seen as proving that you exist in a metaphysically significant way so that you are worth the trouble of inquiring into, of going in search of. Without the former, why bother? This is quite a strange recursion. You want to prove that you exist in the image of the self and of the presence, of the self-presence, that accompanies purposive action or willing. Will requires an object, external or internal, possible or impossible - it doesn't matter if its object is achievable, what matters is the act of will. Somehow the thought 'I am doing this' is an always implicit component of purposive action, but not necessarily through either the purpose or the action. Purposes may be picked up and dropped for the sake of intersecting purposes, they correspond to rôles and exist in a complex nested structure in which we can rapidly shift focus from one to another. They sustain identification, but it is the act or effect of identification that is important, not the details - although much literature and psychology can be made mapping purposes/rôles against each other. As for actions, these are not only nested but are largely executed unconsciously.