  However, Berkeley recognizes that these philosophers have an obvious response available to this argument. This response blocks Berkeley’s inference to (3) by distinguishing two sorts of perception, mediate and immediate. Thus, premises (1) and (2) are replaced by the claims that (1′) we mediately perceive ordinary objects, while (2′) we immediately perceive only ideas.  From these claims, of course, no idealist conclusion follows. The response reflects a representationalist theory of perception, according to which we indirectly (mediately) perceive material things, by directly (immediately) perceiving ideas, which are mind-dependent items. The ideas represent external material objects, and thereby allow us to perceive them.