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There might be truth in that, but don’t you think that it’s easier after the fact to look at the person’s life and say “well this contributed, or that contributed” when we might not really know the weight that those contributions actually made relative to all the other factors? In my case, for example, one might say “well her parents were very intelligent”, or “she had an adequate supply of vitamin D”, or “she got a lot of sunshine and fresh air”, or what have you. </p>
<p>Anything could be seen as a contributing environmental factor - that in itself seems rather vague to me. Wouldn’t just the fact that the person had enough food provided to survive be a “contributing environmental factor” beyond grit, determination, and intelligence?</p>