 Against this background, in order not to be unduly complex a definition of science has to go in either of two directions. It can focus on the descriptive contents, and specify how the term is actually used. Alternatively, it can focus on the normative element, and clarify the more fundamental meaning of the term. The latter approach has been the choice of most philosophers writing on the subject, and will be at focus here. It involves, of necessity, some degree of idealization in relation to common usage of the term “science”, in particular concerning the delimitation of the subject-area of science.