The link demonstrates that there is a well-reproduced phenomenon in real science whereby, e.g., test scores in various academic subjects correlate positively with each other, and that this can be explained by a common psychometric factor that is reasonable to refer to as "intelligence". The IQ or "intelligence quotient" is an attempt to quantify that which is known to exist, and it's actually one of the best understood ideas in the science of the brain.

Additional viewing that largely covers my points below: https://www.youtube.com/watch?v=jSo5v5t4OQM

You started off saying:

> There a lot of pseudoscience around IQ too, probably starting with the very concept of IQ for measuring "intelligence" (for which we would need a strong definition anyway)

The point is that we do, in fact, have all the necessary scientific research to argue that the concept of "intelligence" exists - i.e., that we can identify a single-factor quantity that can be fairly described with a single number - and that anything calling itself IQ is definitionally a measurement of that single quantity.

In particular: problem-solving capability is a real thing, and some people very obviously have more of it than others. Also, we notably don't have data to support more than one factor anywhere near as strong as Spearman's g. (That is to say: we see correlations between academic performance in all subjects - rather than strong positive correlations within certain groups but weak or negative correlations between those groups).

The fact that specific IQ tests might fail to actually measure intelligence, or might measure it inaccurately, is beside the point. The fact that an individual's capability to express intelligence might vary on a day-to-day basis, or for other immediate environmental reasons (stress, caffeine, ...) is also beside the point. Any correlation that any researcher might draw between measured IQ results and any other demographic measurement, mutable or immutable, is beside the point, too.

I have routinely seen people who attack the theory of intelligence engage in pseudoscience of their own, such as trying to invent strange alternate "intelligences" like "emotional intelligence" (apparently meaning some combination of empathy and social skills) and "physical intelligence" (apparently meaning some combination of dexterity and proprioception) so as to "debunk" the idea of intelligence being single-factor (which is not even what the theory of Spearman's g asserts; we're only saying that there is a roughly-measurable quantity that strongly positively correlates with academic success). This is, of course, utterly absurd, and further comes across as an attempt to dunk on "nerds" as "not as smart as they think they are" etc. It only makes sense if you redefine "intelligence" to mean something fundamentally incompatible with the accepted and well understood meaning.

And I, personally, have been called a racist elsewhere on the Internet before, simply for pointing these things out, when I had said nothing whatsoever about race. And I've seen it happen to others, too.

It's infuriating, and it's transparently political.

If I "disrespect" people by dismissing claims like "IQ is pseudoscience" out of hand, I will continue to do so, because I have all the evidence I need that the alternative would lead to far greater societal harm.