The scale, properly speaking, does not permit the measure of the intelligence, because intellectual qualities are not superposable, and therefore cannot be measured as linear surfaces are measured.

Comprehension, inventiveness, direction, and criticism: intelligence is contained in these four words.

Could we look into the head of a Chess player, we should see there a whole world of feelings, images, ideas, emotion and passion

Heredity, to our understanding is not capable of giving to this illness (paraphilia) its characteristic form ... Heredity invents nothing, creates nothing anew it has no imagination.

A person may be a moron or an imbecile if he is lacking in judgment but with good judgment he can never be either. Indeed the rest of the intellectual faculties seem of little importance in comparison with judgment.

Some recent philosophers seem to have given their moral approval to these deplorable verdicts that affirm that the intelligence of an individual is a fixed quantity, a quantity that cannot be augmented. We must protest and react against this brutal pessimism we will try to demonstrate that it is founded on nothing.

The intelligence of an individual in not a fixed quantity.