If perception is the foundational fact for a philosophical account of presence, perception and presence are nevertheless far from being coextensive. A little reflection on a number of familiar facts about our mental life can help us to see why this is so. When I see an airplane fly low over my house, I may actually have it in view for only a few seconds, but after it has disappeared I may still go on thinking about it, for whatever reason, and later in the day (or the month or the year) I may recall this incident and give an account of it to others. Normally we say that on such subsequent occasions we recall what happened at the earlier time; and memory, as our ability to do this, is held to be one of the great departments of mental activity, alongside perception and some others that we have yet to take up. What I remember is that an airplane flew low over my house; and with due modification of the tense of the verb, this is also what I perceived earlier. At the time of remembering, of course, the plane is no longer in view; it may be thousands of miles away or it may even no longer exist. But although it is absent in the sense that it is at least no longer visible, in this absence it is nevertheless, on these occasions of remembering, what I am thinking about. It is accordingly, as we say, present to my thoughts. There is thus, at least in the idiom of everyday life, a recognized sense in which things can be present even when they are absent.