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

I wish that one would be persuaded that psychological experiments, especially those on the complex functions, are not improved [by large studies]; the statistical method gives only mediocre results; some recent examples demonstrate that. The American authors, who love to do things big, often publish experiments that have been conducted on hundreds and thousands of people; they instinctively obey the prejudice that the persuasiveness of a work is proportional to the number of observations. This is only an illusion.

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

The intelligence of an individual in not a fixed quantity.

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 few modern philosopher's assert that an individual's intelligence is a fixed quantity, a quantity which cannot be increased. We must protest and react against this brutal pessimism.... With practice, training, and above all, method, we manage to increase our attention, our memory, our judgment and literally to become more intelligent than we were before.

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.