It is now necessary to point out that there are three kinds of interpretants. Our categories suggest them, and the suggestion is confirmed by careful examination. I terms them the Emotional, the Energetic, and Logical Interpretants. They consist respectively in feelings, in efforts, and in habit-changes. [—]

The majority of signs, in their significative capacity, provoke efforts, whether they be efforts in the outer or the inner world, or whether they be efforts of inhibition, or self-restraint, which make so large a part of the effort to pay attention. An event may provoke an effort of the mind, and not a mere reflex response of the body, without being thereby a sign; but if one becomes definitely conscious, in the provoked effort, of acting against a resistance, or of resisting a force, then the notion of such resistance or such active force is conveyed; and there is a sign.