[yummyfajitas]

You seem to misunderstand the definition of g, as g is not defined in terms of intelligence tests.

Take as your statistic the result of many tests: physics, box loading, french, basketball, etc, and then do a PCA or similar test. One of the principal components will be g, provided you have enough data. This is what defines g.

Intelligence tests are simply tests designed to be more highly correlated with g. If we discarded intelligence tests, we could recreate them (or equivalent tests) based on statistical analysis of the other test data. They are certainly not arbitrary measures.

The external argument doesn't rescue g; g is quite safe. The external argument merely claims that 'g' and 'intelligence' are the same thing, or very close. g exists regardless of what you want to call it.

As for the paper you cite, I skimmed it. Unless I misunderstood it horribly, it merely claims that particular IQ tests don't effectively measure g across different groups. That doesn't mean g doesn't exist as a hidden variable, merely that a particular test is poorly correlated with it for some population.

[emmett]

I've posted this at least three times on Hacker News, but I'm just shocked people haven't read it:

http://cscs.umich.edu/~crshalizi/weblog/520.html

This guy is a statistics professor, and has a lot to say about exactly what "g" is. He even runs experiments! I know the article is a bit long but I promise it's worth reading.

[yummyfajitas]

Well, I admit, I just skimmed it, I'll try to read the whole thing later. But near as I can tell, he isn't addressing the validity of g at all, merely claiming it is unproven that genetic differences between population groups is due to genetics or other factors (a claim I don't disagree with).

[emmett]

You're right; sorry, wrong essay. The other one, by the same guy, addressing that point:

http://cscs.umich.edu/~crshalizi/weblog/523.html

[lolb]

Are there any studies showing that basketball performance, French fluency, bin packing, and physics knowledge, all taken together, will produce a meaningfully large general factor? Intuitively it seems unlikely, and it doesn't jibe with what I understand g's definition to be based on the comments of people like Eysenck and Jensen, who justified g on the basis of intelligence test correlations, and only later tried to tie it to biological functions (evoked brain signal potential in Eysenck's case, reaction time in Jensen's) and metrics of social, sports, and job performance.

Regardless, I agree that g exists in at least a limited sense, but I maintain that there is insufficient evidence to demonstrate that it emerges from innate, immutable physical properties of the brain, and you still can't attribute life success to it.