The reality is that most IQ tests do not go all that high. It is quite challenging to get an accurate IQ score above a certain range. It requires not only the right assessment tools -- ie tests -- but a trained professional administering it. Gifted kids mess with test administrators all the time, sometimes intentionally so. (Plus, to get a super high score, you need to test the child by about age 7. After that age, we just cannot reliably assert that someone's IQ is, say, above 200.)

If the test administered to Feynman only went to 130, as some do, then a test score anywhere close to that, such as 125, can be assumed to have "ceilinged the test." It can be viewed as a floor for the person's IQ, a minimum score suggesting it is at least that high.

Thus, Stephen Hsu's assertion that it must have just been a bad test with a low ceiling suggests to me that Mr. Hsu knows a great deal less about IQ tests than I know, so I see no reason to defer to his opinion.

Yet, also, IQ tests are strongly influenced by cultural knowledge, good scores in kids strongly correlate to kids coming from upper middle class families with well educated parents, etc. So I think there is quite a lot of room for saying that if you take any child and feed them excellently well, dote on them, invest a lot of parental and societal time, effort and other resources in them, they will tend to perform better than average, both on IQ tests and in life generally.

I am not just screwing with people here. I have studied the space and I think there are serious problems with talking about IQ like it is concrete, unchangeable, primarily inherited with minimal influence from environmental inputs, etc.