Hi Mohan

As Jim Stone said earlier in the thread, perhaps you are assuming presentism -- the view that past entities no longer exist in any sense at all.  But that's a pretty radical view with many counter-intuitive consequences.  For example, it has the consequence, barring desperate remedies, that it is not now true that Caesar once crossed the Rubicon. 

I think it is important to distinguish between things in the past and facts about things in the past. I'm saying that the past doesn't exist in the present, by definition. In the case of Caesar, I would indeed say that both the man himself, and his crossing of the Rubicon, are things which no longer exist in any sense at all. I don't think that this is a radical position - it doesn't contradict any statement about the existence, in the past, of Caesar, and the occurrence, in the past, of his crossing of the Rubicon.

Do you want your theory of perception to rest on a metaphysical thesis of this sort?  I would much rather argue for representationalism on cognitive-science grounds ...

I don't actually think of the argument as being metaphysical - to me, it's just an argument about the nature of perception which relies on basic knowledge about both the perception process and the nature of the past and present. However, a cognitive science argument would be preferable in that it would be a more direct argument, if you'll excuse the pun.

With best wishes

Derrick