Abstract

A successor relation between theories T und T₁ express that T₁, the successor of T, has justifiably superseded T. In physics, for instance, Newton's theory of gravitation has superseded Kepler's laws and, in turn, Einstein's theory has become the successor of Newton's. By now there is no agreement on how a general concept of successor relation would have to be construed. In the present paper attention is drawn to two types of such relations, one deductive the other confirmatory. It seems that what most people are looking for is the deductive type of relation. However, a deductive successor relation has to be justified by showing that if it holds then another, confirmatory relation holds, saying roughly that the actual empirical success of the deducing theory is at least as good as the corresponding success of the deduced theory. Under certain restrictions such a justification is given in the paper