Peirce - Introduction

Peirce discovered the idea of the practical:

"A certain maxim of Logic which I have called Pragmatism has recommended itself to me for diverse reasons and on sundry considerations. Having taken it as my guide for most of my thought, I find that as the years of my knowledge of it lengthen, my sense of the importance of it presses upon me more and more. If it is only true, it is certainly a wonderfully efficient instrument. It is not to philosophy only that it is applicable. I have found it of signal service in every branch of science that I have studied. My want of skill in practical affairs does not prevent me from perceiving the advantage of being well imbued with pragmatism in the conduct of life."   Lecture I : Pragmatism : The Normative Sciences, CP 5.14

The applicability of a thought in every branch seems to make it valuable. 

Few persons care to study logic, because everybody conceives himself to be proficient enough in the art of reasoning already. 

An old argument about logic.

"But I observe that this satisfaction is limited to one's own ratiocination and does not extend to that of other men."

"We come to the full possession of our power of drawing inferences the last of all our faculties, for it is not so much a natural gift as a long and difficult art." "Illustrations of the Logic of Scence" First Paper — The Fixation of Belief", in Popular Science Monthly, Vol. 12 (November 1877)

Peirce Summary of his Symbolism in the Encyclopedia: https://plato.stanford.edu/entries/peirce-semiotics/#BasSigStr