Where would Newton stand on the nature v. nurture debate?

I don't believe Newton's work on physics has any bearing on the
question of "nature v. nurture".

I think you will find that Newton was quite religious so you will
probably find that he believed god played a hand in everything.
Personally I am a strong believer of Darwin and the nature debate but
obviously realise that nurture does play a role. However, having had
two children that differ like chalk and cheese dispite a common
upbringing I still give a lot of wieght to the nature argument.