Affect is not a function of any single tendency to action but of the interaction of tendencies. When different tendencies clash we get unpleasant

affect, when they work harmoniously together and integrate to produce some new mode of reaction we get pleasant affect. Owing to its great diffusibility over the elements of a given situation and transferability from one situation to another associated therewith, feeling is only a very rough guide to action, indicating that something should be done rather than what should be done. Cognition arises in the course of mental evolution as a means of producing more definite and specific action—first in the form of images, which reproduce or anticipate situations more or less in their entirety; then in the form of thinking, which possesses greater powers of abstraction and discrimination and which therefore gets further away from the accidentals of a particular situation. These considerations explain to some extent the fact that images are more intimately related to feelings than are thoughts.