Aristotle thinks that in order to remember, (1) one must be cognizant of aphantasmaused as a copy of that of which it is a phantasma,and (2) one must be cognizant of the time at which the original (i.e. now remembered) experience occurred (449b22–3, 450b25–451a8). In De Memoria1, he uses the first half, (1), of this schematic account in order to explain certain kinds of mis-rememberings. For instance, he says that mad people sometimes conjure up fantastic images and take them to be memories of past experience; such episodes are mis-remembering, because these people use that which is not a copy as if it were a copy (451a8-l 1). In De Memoria2, Aristotle returns to the topic of mis-remembering (although it may now be more accurate to call it mis-recollecting1) and here he uses the second half, (2), of his schematic account, together with the first, in order to explain additional sorts of mistakes. He claims that we sometimes recall the image of an event and properly use it as a copy, but we get the time wrong (thinking, for example, that an event occurred a week ago, when actually it occurred yesterday), and thus we fail to remember; further, he claims that we sometimes get the time right, but fail to use an image as a copy of the events which occurred during that time. In each case we fail to remember; for in order to remember we must both use an appropriate copy as a copy and (more or less) accurately cognize the time (452b27–9).