John Wright challenges the concept of IQ:
Since I am apparently one of those self deceived idiots, allow me to say that the predictive ability of people who do well on one kind of intellectual test to do well on another kind of intellectual test is not science. It is not the empirical measurement of an observable reality.
I could with even greater accuracy predict that the winners of beauty pageants will be shapely women who are in favor of world peace.
I can also predict she will wear a crown and carry a bouquet.
No matter how accurate such a prediction, it is not science. Beauty is not a thing that can be measured and neither is the degree of craving for world peace.
It is (at best) confirming a correlation. This is not the same as Newton determining the laws of gravity from which accurate descriptions of falling apples and orbiting planets can be deduced mathematically.
Such are the perils of a philosopher wading out into the perilous waters of science. What is not observable about an intellectual test? What is less empirical about a percentage of correct answers than a quantity of inches or a measure of weight? And, of course, the science of intelligence goes far beyond people taking two or more intellectual tests. It is no less scientific than any other branch of genetic science, in which the birth of a baby with blue eyes can be predicted or the disease of a child yet unconceived can be anticipated on the basis of his parents’ genetics.
Science does not require precisely defined measurements to be science. It need only be observable, testable, and repeatable. The fact that it is harder to agree upon a measure for intelligence than one for height does not mean that intelligence is not observable or that the predictive model is unreliable. John appears to be erroneously targeting the fuzzy metric presently used to quantify intelligence and thinking this is sufficient to call the entire science into question.
Would he also claim that weight does not exist or is unscientific? After all, it is even harder to predict the adult weight of a baby than his IQ on the basis of his parents. As other commenters have pointed out, we have a pretty good idea of the heritability of g, so how can it be reasonably asserted that there is no use of the scientific process being utilized? We have seen and observed a considerable number of relevant hypotheses being tested, both formally and informally, after all.
And beauty, at least in some of its forms, can be measured, as the picture below demonstrates.
