IQ confusion

It was difficult to ignore Rosalind Arden's many fallacies ("g whiz! IQ is a clever concept", THES, December 3), even before Ken Richardson's subsequent demolition (Letters, THES, December 10).

Thus: g "is a construct" arising from measurements (indeed because it does so). It is also "the core discovery (sic) of intelligence research". The implicit category-mistake is evident if one asks if Arden would support research to discover the essential nature of the retail prices index.

Mystifyingly, Arden writes: "It (g) is so much less confusing than talking about intelligence ... g is the active ingredient of intelligence". That sentence has the logical form of "hydrogen peroxide is the essential ingredient of hair bleach".

By common standards we are here talking about bleach (of which we have to have some prior notion - however fuzzy - for the assertion to be intelligible). But Arden assures us how less confusing it is not to talk about intelligence. Just who is confused?

G. Colin Jimack London NW7