Abstract
Analogy as a scientific method has been criticized during the last decades; only for heuristic purposes it has been accepted. On the other side especially proportional analogies have a long tradition in European thought since Plato and Aristotle, for, as Aristotle puts it, analogies allow a connection between different and unbridgeable ontological areas. As examples for such connections the analogia entis of Thomas of Aquino and the Kantian Analogies of Experience are discussed. They give us hints for a new view of analogies, which during the Middle Ages were not only of heuristic value, but were accepted as a proof: Analogies do not only produce hypotheses, moreover, they build up new views of the world, they are the background of paradigms, for they create structures by introducing similarities and proportions.