Why sensation should compel our belief of the present existence of the thing, memory a belief of the past existence, and imagination no belief at all, I believe no philosopher can give a shadow of reason, but that such is the nature of these operations. They are all simple and original, and therefore inexplicable acts of the mind.
Philosophers indeed tell me, that this immediate object of my memory and imagination in this case, is not the past sensation, but an idea of it, an image, phantasm, or species of the odour I smelled; that this idea now exists in my mind or in my sensorium; and the mind contemplating this present idea, finds it a representation of what is past, of what my exist, and accordingly call it memory, or imagination.(from An Inquiry into the Human Mind, on the Principles of Common Sense by Thomas Reid)
Writing in her essay on Memory and the Past Elizabeth Anscombe:
Then what makes my state or act of consciousness memory of the thing. Is it the mere fact that the thing happened and that I witnessed it? In that case there is nothing in the memory itself that makes it refer to the actual past event. And if so, why should the experience of memory have anything to do with actual past events or show one what it means for something to have happened?
She then in her consideration of the phenomenon of memory examines the present experience of which memory is supposed to be.
But if I consider some present thing (which can, if you like, be a state of mind) and my future ability to speak of it, it is brought out more clearly how difficult it is to make out that anything I may attribute to my future mental state will make what I say refer to this.
Is she moving towards a Reidian rejection of ‘ideas’ or the perhaps lesser claim that representations cannot bear the weight of memory. It is significant that the pramana theory of the means of valid knowledge does not accept memory as a free-standing means of knowledge. That is a side issue, I merely bring it up as a link to the concept of the pramana as an irreducible means of knowledge. In this system Perception stands on its own. Inference cannot be reduced to an instance of perception. Each pramana is irreducible.
Further down she writes:
In general we must fail if we try to explain the sense of statements about the past by means of present memory, consciousness of meaning, quality of images, or anything else of the kind. For either we have left out all reference to the actual past, or we have surreptitiously introduced it into an explanation that proposed to do without it.
Even though the focus of her paper is on the reality of the past, one can see that here she is pointing towards the Bergsonian idea that a memory of a past event is not got through an image. A memory is of the past but is not of the past through the memory. There is an irreducible aspect to memory and that is mysterious. Just this oddness of what we take for granted is philosophy is doing its work.