Full Idea
The object of reasoning is to find out, from the consideration of what we already know, something else which we do not know.
Gist of Idea
Reason aims to discover the unknown by thinking about the known
Source
Charles Sanders Peirce (The Fixation of Belief [1877], p. 7)
Book Reference
Peirce,Charles Sanders: 'Philosophical Writings of Peirce', ed/tr. Buchler,Justus [Dover 1940], p.7
A Reaction
I defy anyone to come up with a better definition of reasoning than that. The emphasis is on knowledge rather than truth, which you would expect from a pragmatist. …Actually the definition doesn't cover conditional reasoning terribly well.