Because we’re talking about the same thing in a different language. "Genetics* only mean the instructions used to build the structure of our intelligence. They’re not wrong at all, our determination nature is the result of the structure of our neurons which has a fundamental configuration determined by genetics. [citation needed] No, it doesn’t invalidate it because the twins could be fraternal, having separate DNA, Yes, I assumed that we were only talking about identical twins. or that could have had such extreme differences in environment that it drastically changed the DNA from the shared base. Excluding those, though, and you can see the deterministic nature of life shining through. What about identical twins who did not have extreme differences in environment but who nevertheless turn out quite different? Would you agree that even one example of such a set of twins would falsify your claim?