The notion of habit occupies a central position in Peirce’s pragmatism. Habit entails a disposition to act in certain ways under certain circumstances, especially when the carrier of the habit is stimulated, animated, or guided by certain motives (Peirce CP 5.480). The meaning of a Peircean sign is most adequately understood through the habits of action they provoke, sustain, and modify.
When somebody says a diamond is “hard”, that person means that a diamond’s nature includes the ability to cut glass and other substances.
That person’s disposition to conceive of a diamond in this way — rather than conceiving it for ornamental purposes — constitutes, pragmatically, what “hardness” means, and “diamond” means in terms of its characteristics and its nature. If that person had once considered diamonds strictly in terms of rare gems and ornamentation, then the characteristics and nature of diamonds were previously something other than they now are. Consequently, the meaning of “diamond” changed when a diamond became a means for qualifying “hardness”.
Pedro Ata & Joao Queiroz