How did Peirce use the example of hardness to explain pragmatic meaning?

To explain the pragmatic meaning of a concept, Charles Sanders Peirce proposed that we must consider the practical consequences that an object of our conception might have. He argued that our entire understanding of an object is defined by our conception of these potential effects.1

Peirce used the example of "hardness" to illustrate this method of clarification. To say that an object is hard is not merely to describe an abstract quality, but to provide a conditional statement about how that object would behave under specific circumstances. Specifically, he explained that saying an object is hard means that if one were to perform the operation of scratching it, the object would not be scratched by most other substances.1

By translating the concept into a testable, conditional operation, Peirce demonstrated how to resolve conceptual confusion and achieve clarity regarding the meaning of our ideas.1