Pragmatic Maxim

It appears, then, that the rule for attaining the third grade of clearness of apprehension is as follows: Consider what effects, that might conceivably have practical bearings, we conceive the object of our conception to have.  Then, our conception of these effects is the whole of our conception of the object.

-- Charles Sanders Peirce (1839 - 1914), American scientist, logician, and philosopher, original statement of the Pragmatic Maxim, p. 293 of "How to Make Our Ideas Clear", Popular Science Monthly, v. 12 (1878), pp. 286-302