I've been studying Locke's An Essay Concerning Human Understanding for an empiricism class this semester and I stumbled upon a particularly interesting epistemological problem in reading the section about sensitive knowledge. Locke says that sensitive knowledge is knowledge of the existence of particular things. So I have sensitive knowledge when I perceive anything to exist. This kind of knowledge is limited to immediate sensory experience. Locke also thinks that our memory of the existence of particular things constitutes knowledge beyond all doubt provided that our memory remains intact and unchanged. That seems a bit problematic to me though. I don't even think a person could know whether or not their memory has remained true to fact. So it looks like the knowledge gained at the time of some immediate sensory experience is very strictly limited to immediate sensory experience. It's not like I have any way of verifying whether my memory of some experience is correct or not. Of course, in a large class of cases one's memory of a certain experience can be compared to the other peoples' memory of that same experience. So maybe the testimony of other people is a criterion of objectivity in such cases, and there are other ways testimony comes into the picture even in cases where the question is concerning an experience that only one has had. I haven't thought too much about that one. I'll provide an excerpt from something I wrote to get my point across. My argument uses the case of one person's experience. The experience involves an instance of a bird flying by. Assume that in the world where I am having this experience I have never seen a bird and neither has anyone else. Just to clarify something, the point about the description not being some arbitrary name might have been stated differently. What I probably should have said is that even if the description is being used referentially, acknowledging that in no way makes it any clearer that I would be referring to that bird that I saw on that day. It's not as if I am just using the description referentially. I am referring to something which I think exists and which satisfies the description. So the description can't act as a name and it has its truth condition necessarily. Anyway, my point is, how do you confirm that your memory of something, particularly some private experience, is true to fact? Any thoughts on this? I'm not too familiar with the subject so I'm not sure if the same problem's been brought up before but I think it's interesting. Maybe, as I suggested earlier, testimony and shared or similar experience is a criterion of objectivity.