Impression of "Self"

David Hume said we have no "self". If we have a "self", we should have an impression of it, but he went into his mind and try to find "self", all he could find is memories and other impressions. Therefore, there's no "self", and self is an imagination.

Sounds logical, but here is a problem. In Hume's way of saying, do we really have an impression of apple? We have impressions of apples, but all apples are different, how can we define one is an apple although our impression of it varies from the impression we have of the apples we saw previously? What "real" impression we have that as a combination create the whole impression of an apple? Colour? Shape? Smell? No two apples have absolute identical colour, shape and smell, that means we never have one single impression of an apple. This problem may show clearer on dogs. You see a little thingy walking running around with his tongue out, you never see this breed of dog, but then you just realise it is a dog. How does your existing impression of "a dog" have in your mind help you to identify it is a dog? How do you know it is not something else? Do we ever have a single impression on something, or eventually all we know are bundles of impressions and memories about something?

There is another problem, let me explain this in an analogy. If something exists physically, my left pointer finger should be able to point to it. Maybe that thing is too far, but if you bring it closer, I can always point to it. Maybe it is on my left pointer finger, but if you bring it away my left pointer finger I should be able to point to it. However, my left pointer finger cannot point o one thing -- which is my left pointer finger. Does this means my left pointer finger does not exist? If there is a "self", then "I" would have an impression of it, but I can't find the impression of it, so thereis no "self". Well, who is the one would have or should have the impression? Isn't that what your "self" is?