ABSTRACT

Propositions are the nucleus of scientific knowledge, because they can be testably true or false. 1 A proposition which expresses a testable but not yet exhaustively tested state of affairs is normally called a hypothesis. In all experimental sciences a hypothesis or a system of hypotheses is confirmed by empirical testing. When in these tests a hypothesis regularly holds its truthfulness and thus expresses general aspects of reality, it is no longer regarded as a hypothesis but as a scientific law. This means that laws are verified regularities. 2 In cognitive psychology, for example, the phenomenon of the serial position curve has a law-like status. It has been replicated numerous times and there is very little doubt of its reality. 3