Earlier quoted context omitted.
Why is everybody so binary about this? Are we really suggesting that some individuals are not capable of intellectual tasks at a greater capacity, or a greater speed than others? If you understand that a human being has a higher cognitive function than a sea slug, a wasp, a mouse, a dog, a dolphin, an ape, by our genetics alone, then you have to accept that there is a degree of genetic variance between individual hum…
"Genetics" is the new God. Apparently people assign whatever they don't know or understand to genetics. Can't play football? That's genetics!! Knows math? More genetics!! Are actually there studies that claim a special ability is due to genetics only?
Whether it's higher endurance, a tiny difference in bone structure, longer arms, greater height, etc. - that's all mostly genetics with a bit of environmental factors mixed in (like childhood nutrition)
But cognitive abilities and intelligence are far less understood, because you simply can't measure it as well as physical achievements (in fact, some of the top comments here gripe about using a PhD degree as a benchmark for achievement; or patents; or publications; or even income level)