I will consider here the meaning and the role of the irrational in a number of human works, in several major creations of the human spirit, and specifically in scientific works. With this in view, I shall distinguish between three significant types of the irrational.
The first concerns irrationality as an obstacle; in this case it acts as the spark that will lead to the triumph of rationality. The second concerns the irrational as an expedient or as a means of renewing and prolonging the creative act. The third, which comes to irrationality through renunciation, is to all intents and purposes a complete rejection of rationality.
This three-fold differentiation will guide us in our ensuing study of the irrational in the works to be examined, in a spirit of open and dynamic rationalism with a view to recognise and limit the positive role of the irrational.?