This still crops up occasionally as a ‘controversial concept’ so it’s worth putting up a quick-and-easy docking-port to the informed mainstream position.
… the evidentiary base regarding the existence of general intelligence and its ability to predict important life outcomes — including health, longevity and mortality, as well as other key variables — is beyond compelling, it’s overwhelming. And if you find yourself feeling like you can do damage to this evidence base by invoking arguments about “multiple intelligences” or something of the sort, let me save you the effort. Those urges illustrate unfamiliarity with any of the serious research done on the topic in the last several decades. If those urges haunt you, I’d recommend Stuart Ritchie’s excellent primer on the topic. The waters of intelligence research, though controversial, no longer require that you be Magellan to navigate them. As we will see below, however, it is only one small step from banal psychometric work on IQ, to the mother-load of academic controversy. Stay tuned. …
For most here this will be redundant. The next (edgier) stage will also be redundant. It’s posted here almost as much in appreciation of its exasperated tone as for its linkage.
Gottfredson, cited in the post is the author of ‘Mainstream Science on Intelligence’ (1994), still after more than two decades probably the best short primer. The Wikipedia summary is here (with some commentary, and useful linkage).