The philosophy underlying medical informatics, and indeed information systems in general, is discussed. The need for integrating concepts is considered, and particular emphasis is placed on the avoidance of fragmentation and overspecialization. Human and artificial intelligence are compared and contrasted. It is shown that human intellectual activity cannot be reduced to a set of formal computations. The main emphasis of this paper is that the unique properties of human intelligence should not be devalued or ignored in attempts to promote machine systems in unappropriate areas.