When affectivity, i.e. feelings and moods, are referred to in connection with the acquisition of knowledge, it is customary for the way in which they disturb cognition or even distort truth to be placed in the foreground of discussion. Knowledge is considered as mediation of what is "objective," in all the complex meaning of this word. By contrast, the world of feeling appears as the realm of subjectivity. What can it do but impair understanding? Thus it is usual to exclude feelings and moods as far as possible where knowledge is concerned, especially scientific knowledge.