> I'd love to know your source, because I doubt the number of “twins that have been raised apart ” is large enough to be a statically significant cohort even if you could have them all in your study.

This, among others:
https://pubmed.ncbi.nlm.nih.gov/2218526/

> Yes, some people are born without legs. And some are born with Down syndrome, nobody disputes that.

I see you haven't debated many blank slaters. The original post I responded to said, "What matters is not the brain but the education they get". That is literally false.

> if you take a random sample of 20 Americans of the right age, you'd have insane disparities, with a significant number not being able to run the distance at all and struggling to finish in less than a minute, despite their completely functional genome.

Yes, and you will find cases of people who ate basically the same diet and were just as active or sedentary who fall on both sides of that line of finishing/not finishing. Some people will just have a more efficient metabolism, or a more robust skeletal structure, or greater lung capacity, or more type II muscle fibers, and the positive confluence of all of these factors makes a great natural athlete, and a negative confluence on all of them makes for an unlucky individual who will likely never be athletic no matter how hard they try. Which doesn't reduce the importance of being fit, or reduce their human worth, but there's no point denying the obvious.

All of these factors fall within natural human variability, and all of these factors are influenced by environment of course, because genetics and environment can't be trivially separated, but the point is that it seems like these factors have multiplicative effects. Such factors exist for cognition as well, and the same conclusions follow. This counts as architecture.

> The actual argument is that when in my previous 100m example you have genetics variation with an impact of at best 30%, and a observed variation of more than 500%, it's fair to say nurture is the dominant factor.

Nurture is probably the dominant factor in almost all cases throughout the world because of malnutrition. It remains the case that even if you eliminate all environmental disparities, humans will still exhibit considerable variability on all traits. Some will still be natural gifted athletes and naturally gifted mathematicians, and some significant fraction will simply be below average on many categories, and some unlucky few will be below average on all categories, and not due to any obvious deficiency like Down's.

I'm not even going to bother addressing the irrelevant comments on Murray and his book, mostly because I haven't even read it. This is all standard statistics and genetics.

The original matter I disputed was literally false, as I said above, but the spirit of the comment was that data matters more than architecture. I think that's a very premature conclusion. It would be more correct to say that a) you can equate outcomes by varying data despite the architecture, but b) some architectures scale better (do more with less data), and I would add c) no known architecture scales as well as human cognition yet, which suggests better architectures remain to be found, and this suggests d) that architecture does matter.