Just as a point of clarification I think we all have to keep in mind the difference between a reliable result and a valid claim  I dont think it would be possible to claim that g is not a reliable result  as Bpesta said its been replicated far too many times to say its just an artifact  The debate is over what this reliable result means eg which theoretical claim about the underlying cause of the effect is valid and that is a complex multisided yettoberesolvedifever question  Frankly I doubt science will have a decent answer to that question until it has a more analytic definition of what intelligence is and being a bit of a developmentalist myself I suspect that that definition will be much more subtle than can be captured by a simple measure like IQ but as it stands the best we are going to be able to do with this section is discuss g in its basicsand then lay out various interpretations with proper attributions so that it doesnt look like the section is advocating any one amongst the several competing ideas