I've always viewed genetics and talent as essentially your maximum potential. Lots of ways to drag you down from being all that you can be (lead, malnutrition,

I've always viewed genetics and talent as essentially your maximum potential. Lots of ways to drag you down from being all that you can be (lead, malnutrition, a good knock on the head), but given a sufficiently good environment, genetics (or perhaps inherent ability might be better) then become the limiting factor on how far you can go. Your random guy on the street ain't going to be Newton, no matter how much he studies or loves math. Similarly, the man born with muscular dystrophy isn't going to be setting marathon records. This is a simplification of course, but I hope it conveys the point.