The author argues that the intelligence test debates amongst professional psychologists result from the participants’ conflicting styles of thought. At present, both extreme views – either blind belief in high validity of intelligence tests or refusal to use them because of faults in testing procedure – are unacceptable. The author criticises the explanation of practically all aspects of life (study, work, conflicts etc.) by correlation arguments. Until now, the validity of intelligence tests has not been proven: their construction has no relation to the person’s competence in various areas of life; they do not take into account the specialisation of individual abilities; they are not sensitive to the dynamics of individual development, which can be influenced by the «factor of a chance event». The use of tests raises social and ethical problems. In unprofessional hands, they are often damaging to the individual’s interests. Tests can be used providing there are all the right conditions, but not for discriminating people and, above all, children on the basis of their IQ.