C. S. Peirce Manuscripts

πλ 1 Prolegomena to an Apology for Pragmatism

Come, reader, let us construct a diagram to illustrate the general course of thought. "Why do that when the thought itself is present to us?" Such, substantially, has been the objection raised by more than one or two superior intelligences, among them by an eminent General. Recluse that I am I was not ready with the counter-question, which should have been, "General, you make of use of maps during a campaign, I believe. Why do you so, when the country they represent is right there?" Thereupon, had he replied, that he found details in the maps that were not "right there", but were in the enemy's lines, I should have pressed the question, " Am I to understand, then, that if you were thoroughly and perfectly familiar [...]

πλ 3 experimentation as putting questions to "nature," experiments upon diagrams are questions not to the nature of the relations concerned." Maybe, the general would suggest that there is a good deal of difference between experiments like the chemists, which are trials made upon the very substance whose behavior is in question, and experiments made upon diagrams, which has no real connexion with the things the diagrams represent. The proper response to that and the only proper one making a point that a novice in logic would be pretty sure to miss, would be "You are entirely right in saying that the chemist experiments upon the very object under investigation, although, after the experiment is done, the particular sample operated upon may be thrown away, as having no further