In the course of history, few diagnostic instruments would attract as much attention as intelligence tests. The continuous interest in intelligence and its measurement is reflected in scicntific discussions on the subject. In this article we report on a reconstruction of shared presuppositions implicitly underlying scientific discussions about the educational uses of intelligence tests in the period of their first introduction (1900-1940) in the Netherlands. Special attention is paid to presuppositions about the nature of intelligence, about the possibilities of influencing its development by educational means, and about the specific educational aims to be achieved by the use of these tests. The results are interpreted as part of developments in social and ideological history.