memory the retention of, or the capacity to retain, past experience or previously acquired information. There are two main philosophical questions about memory: (1) In what does memory consist? and (2) What constitutes knowing a fact on the basis of memory? Not all memory is remembering facts: there is remembering one’s perceiving or feeling or acting in a certain way – which, while it entails remembering the fact that one did experience in that way, must be more than that. And not all remembering of facts is knowledge of facts: an extremely hesitant attempt to remember an address, if one gets it right, counts as remembering the address even if one is too uncertain for this to count as knowing it. (1) Answers to the first question agree on some obvious points: that memory requires (a) a present and (b) a past state of, or event in, the subject, and (c) the right sort of internal and causal relations between the two. Also, we must distinguish between memory states (remembering for many years the name of one’s first-grade teacher) and memory occurrences (recalling the name when asked). A memory state is usually taken to be a disposition to display an appropriate memory occurrence given a suitable stimulus. But philosophers disagree about further specifics. On one theory (held by many empiricists from Hume to Russell, among others, but now largely discredited), occurrent memory consists in images of past experience (which have a special quality marking them as memory images) and that memory of facts is read off such image memory. This overlooks the point that people commonly remember facts without remembering when or how they learned them. A more sophisticated theory of factual memory (popular nowadays) holds that an occurrent memory of a fact requires, besides a past learning of it, (i) some sort of present mental representation of it (perhaps a linguistic one) and (ii) continuous storage between then and now of a representation of it. But condition (i) may not be conceptually necessary: a disposition to dial the right number when one wants to call home constitutes remembering the number (provided it is appropriately linked causally to past learning of the number) and manifesting that disposition is occurrently remembering the fact as to what the number is even if one does not in the process mentally represent that fact. Condition (ii) may also be too strong: it seems at least conceptually possible that a causal link sufficient for memory should be secured by a relation that does not involve anything continuous between the relevant past and present occurrences (in The Analysis of Mind, Russell countenanced this possibility and called it ‘mnemic causation’). (2) What must be added to remembering that p to get a case of knowing it because one remembers it? We saw that one must not be uncertain that p. Must one also have grounds for trusting one’s memory impression (its seeming to one that one remembers) that p? How could one have such grounds except by knowing them on the basis of memory? The facts one can know not on the basis of memory are limited at most to what one presently perceives and what one presently finds self-evident. If no memory belief qualifies as knowledge unless it is supported by memory knowledge of the reliability of one’s memory, then the process of qualifying as memory knowledge cannot succeed: there would be an endless chain, or loop, of facts – this belief is memory knowledge if and only if this other belief is, which is if and only if this other one is, and so on – which never becomes a set that entails that any belief is memory knowledge. On the basis of such reasoning a skeptic might deny the possibility of memory knowledge. We may avoid this consequence without going to the lax extreme of allowing that any correct memory impression is knowledge; we can impose the (frequently satisfied) requirement that one not have reasons specific to the particular case for believing that one’s memory impression might be unreliable. Finally, remembering that p becomes memory knowledge that p only if one believes that p because it seems to one that one remembers it. One might remember that p and confidently believe that p, but if one has no memory impression of having previously learned it, or one has such an impression but does not trust it and believes that p only for other reasons (or no reason), then one should not be counted as knowing that p on the basis of memory.
See also EPISTEMOLOGY, PERCEPTION , SKEPTICIS. C.G.