The Commens Dictionary
Quote from ‘Reasoning [R]’
…a doubt is a real state of dissatisfaction; and the common practice of making believe to doubt, and then offering considerations to appease that make-believe doubt, is a foolish waste of time, since the man who does not doubt can realize the state of mind of the man who does […] only to a very limited extent, and he thus quite fails in all difficult cases to appease any real doubt that may exist, or appeases it quite otherwise than by his attempted reasonings.
MS [R] 753:4
‘Doubt’ (pub. 19.10.15-18:19). Quote in M. Bergman & S. Paavola (Eds.), The Commens Dictionary: Peirce's Terms in His Own Words. New Edition. Retrieved from http://www.commens.org/dictionary/entry/quote-reasoning-r-0.