The movie Proof

What is the whole idea of the movie...what was the thought behind it?

Why does the blind photographer (Hugo Weaving) behave the wat he does with the housekeeper?

What does he want from life..is it that he does nto want to feel helpless and so does not give in to developing relationships easily? He does not trust anyone?

But if someone loves him (like the housekeeper does) why doesn the allow that..isnt he too lonel;y.

My point...what is the director point of view...the essence of the story which triggered the film in the first place?

Anyone here who can surmise that??