In your example, we have no reason to privilege the hypothesis that there is an underlying causal factor behind that data. In the case of g, wouldn't its relationships to neurobiology be a reason to give a higher prior probability to the hypothesis that g is actually measuring something real? These results would seem surprising if g was merely a statistical "myth."
In the case of g, wouldn't its relationships to neurobiology be a reason to give a higher prior probability to the hypothesis that g is actually measuring something real?
The best evidence that g measures something real is that IQ tests are highly reliable, i.e. if you get your IQ or g assessed twice, there's a very good correlation between your first score and your second score. Something has to generate the covariance between retestings; that g & IQ also correlate with neurobiological variables is just icing on the cake.
To answer your question dire...
This thread is for the discussion of Less Wrong topics that have not appeared in recent posts. If a discussion gets unwieldy, celebrate by turning it into a top-level post.
Part 2