Nature is everything, nurture is nothing except where it interferes with natural development. By this I mean, if you starve a child, the child's brain won't develop naturally, and the child will have a lower IQ than he should have had, according to his genetics. If you lock a child in a dark room every day and never talk to him, he will not learn to speak because his brain is not exercised. This is nature being impeded by environmental factors. But in themselves, environmental factors contribute nothing. They can only take away, never give.