Speaking generally, we can say that the thinking function always operates by way of comparison; that is, that intellectual conclusions are the result of comparison. Feeling and sensing, on the other hand, are not rational functions. They do not compare but simply define a given impression by its aspect—by its being pleasant or unpleasant in one way or another, or by its sensory perception, such as its color, taste or smell. Moreover, sensations can be
indifferent—neither pleasant nor unpleasant. In the sensation of “white paper” or “red pencil,” there is nothing based solely on color that is inherently agreeable or disagreeable. But feeling functions or emotions are always pleasant or unpleasant; there is no such thing as an indifferent emotion.