It isn’t society as a whole or even a random collection of members that hands on the stock of scientific knowledge but a more or less definite group of professionals who teach the rising generations not only their methods and results but also their opinions about the direction and means of further advance. In a majority of cases competence in doing scientific work cannot be acquired, or can be acquired only by individuals of quite exceptional originality and force, from any source other than the teaching of recognized professionals. (1)