If you believe in evolution, you have to believe in the genetic determinism of genes.
Sure, there is leeway for nurture, but a lot of people are holding contradicting opinions (they believe in evolution but not as much in "nature") because we as a society are hiding the truth of human determinism.
Evolution is simply three observable phenomena: first, living things carry genetic information; second, genetic information is rarely transmitted without any change to a descendant; third, a living thing that does not have descendants doesn't directly contribute their genetic information to any descendants.
There's nothing there to "believe" in any more than you need to believe in gravity.
Next, everything that happens to an organism that is not determined by genes is determined by the rest of the universe. That's pretty obvious.
A really interesting aspect, though, is that genes can't do anything if they aren't being read and processed correctly. Reduce the supply of essential nutrients, and it doesn't matter how awesome your genes are, you're going to get a deficiency disease. Fill the environment with chlorine compounds, and you're going to get poisoned. Too much lead? Too much alcohol? Say goodbye to proper development.
When it comes to humans, it's even worse. If you don't interact with them enough, they don't develop well. Language skill has a few years to develop properly -- without society, humans can't function in society.
None of those results suggest that we are hiding some sort of determinism that we should be paying more attention to.
There is a very hard species boundary, so it must be something that is giving to the offsprings.
If you further accept that the ability to learn advanced math does not fall from the sky and we somehow descended from an ancestor that did not have this ability, then the only way we got here is that (something that correlates to) this ability was heavily selected for in the past.
And you need some kind of continuum (it can also be multi-dimensional) where you can gradually converge to. I don't think this is something that spontaneously emerged.
If you accept all this, then the same things will likely still play a role within current humans.
Evolution works through genes (well, mostly). That doesn't say other things have zero effect, and I'm really curious about what led you to think so.
Most likely you will slam me for the lack of rigor in my comment, which is fine, I don't have the time to spell it out and provide studies.
The determinism part doesn't follow. Evolution works on probabilities, so you have to believe that genes influence the outcome. Influence. That's all that's needed.
Worse it comes absolutely loaded with social and political implications. It doesn't describe anything we can really point to, but is just a highly charged, culturally variable label we place on a cluster of outward appearances (e.g. excess or lack of melanin, hair or eye color, height).
You might be able to tell if a particular individual is likely to have a lack of melanin or blue eyes from DNA, but you can't say genetic differences are caused by race. That in the famous words of Pauli is not even wrong.
It's a category error, and even if it were useful it also inverts the causality. We apply the label "race" to a cluster of possibly DNA influenced outward markers. We humans cause "race" and apply it to people. Not genetics.
Using a poorly defined term like race in an argument like this is worse than just poor reasoning. It will confuse people at best and cause harm at worst.
It's not unacceptable because people are afraid of the truth or something.
It's unacceptable because it's incoherent, vacuous and empty. It adds nothing to the discourse.
Either you're making a scientific point or you're just complaining that people get upset when you discuss race. Which is it?
I am 5'10" tall, born and raised in Western society. I am taller than my most of my ancestors, but only marginally taller than my father. He grew up in India, but his family was non-vegetarian in a village of pure vegetarians.
We might have been able to be a little taller if we understood nutrition a bit better, but it's probably within an inch or so. Our height is limited by genetics, not by environment.
It stands to reason that if physical attributes like height are subject to genetic determinism, aspects of our brain & mind should be too. Now, comparing brains to height is very reductive, since the brain is infinitely more complex. But there's a probably a pretty good reason why my father and I have very good memories, and are fairly intelligent people. But we're also not superstar athletes, or great artists. Genetics and environment have optimized our brains in a certain way. And I'm already seeing the same traits in my 1 year old son.
But isn't that the beauty of genetic determinism? Isn't that the beauty of all of us having vastly different life experiences? I don't lament the fact that I don't have the genetics of Usain Bolt, but I can admire and appreciate his prowess. Similarly, I don't lament the fact that I'm not a great creative like Picasso or Mozart. Something about their genetics and environment allowed them to achieve greatness in areas I am not capable of. And that's fantastic, because our society is enriched because of this diversity.
I think a society that celebrates the individual, gives them the resources and environment to achieve whatever they're capable of, and thus, reach the limits of their own genetics is one I'd like to live in. Realistically, most of us are not even close to be limited by our genetics, but man, how awesome would it be if we were?
And if you don't believe in creationism and also don't believe that intelligence is subject to evolution, then you need some very good explanation where intelligence comes from in the first place.