Abraham and Jewish History?!?

[solja247]

I have spent a bit of time looking at the historicity of the Bible, mostly Moses, Abraham and other patriachs. I was reading a lot of skeptic 'mainstream' archaeology and history, saying that Abraham did not exist and was a fabrication, I went to a friend of mine, a biblical scholar, and he asked me a powerful question; Why should we not believe Abraham existed? People want evidence for Abraham's existence, but isnt that absurd? Should we expect evidence? My skeptic mind had no answer, after all, there are large gaps in history, massive gaps, perhaps we should be a little more careful when dismiss historical characters, such as Abraham?
Another thing to take into consideration, is the fact that the Jews had a very very very strong oral tradition. We should NOT dismiss oral, espicially if there is no reason too. Oral tradition is what people used, a fine example of this is the rainbow serpent, in Aboriginal's mythology they believe a rainbow serpent created Australia (or the world?) we know they believe this through oral tradition, they didnt write, they drew and had symbols. Never the less, relied HEAVILY on oral tradition and we take their oral traiditions as being credible, being passed down from generation to generation for thousands of years. However, for some reason, people dismiss the Bible as quick as they can, and largely have no reason why, they dismiss Jewish history (Although they dont dismiss other culture's history) as being 'made up' by the Religous leaders, being copied from the Epic of Gilgamesh and other sacred mythological texts. Is this a reasonable conclusion to come too? Why should we believe that Abraham did not exist?