MathJakob said:
Of course some people are born a genius, how can you explain a 6 year old solving differential equations or a 14 year old just starting his phd in theoretical physics?
I think anyone who truly believes that all humans are born equal is just stupid. Sure if you work hard and study you can achieve a lot in life, but there are others who are simply born to be great at something. The 14 year old I'm talking about is Jacob Barnett and at 3 years his mother found him calculating the volume of various cereal boxes lol, without being taught about it (so she says). This shows a natural genius.
http://www2.macleans.ca/2013/09/01/jacob-barnett-boy-genius/
And one of his little brothers is a biochemist and the other is a meteorologist (at least according to Barnett's TED talk). Clearly, something in that family is special (even though I wonder just a little bit how much of his story is real).
But it's not just genetics. The environment a person lives in plays a pretty big part, too. There's a big difference between someone like
David Hahn, who tried to build a breeder reactor in his backyard shed but instead created an EPA superfund site, and
Wilson Taylor, who created his first bomb at 10-years-old and his first nuclear fusion reactor at 14-years-old.
There's no reason mental abilities should be any different than physical abilities. When 17 Americans in history have run a marathon in under 2 hours and 10 minutes (with America being a reasonably random genetic sample due to its history of immigrants) and 32 members of the
Kalenjin tribe of Kenya ran under 2:10 in a single month (October 2011), there's clearly something about that tribe's genetics, environment, and/or culture that provide them with an advantage in running long distances. (There was a time when one might think they just trained differently, but knowledge spreads and modern training techniques have only increased their domination).
The only real difference is that a person's natural mental abilities are a lot more difficult to measure than their physical traits and, even if one could, their natural ability in itself wouldn't predict whether they'd actually become a "genius" as measured by their accomplishments.