The Commens Dictionary

Quote from ‘A Neglected Argument for the Reality of God’


… constitutes the Second Stage of Inquiry. For its characteristic form of reasoning our language has, for two centuries, been happily provided with the name Deduction.

Deduction has two parts. For its first step must be by logical analysis to Explicate the hypothesis, i.e. to render it as perfectly distinct as possible. This process, like Retroduction, is Argument that is not Argumentation. But unlike Retroduction, it cannot go wrong from lack of experience, but so long as it proceeds rightly must reach a true conclusion. Explication is followed by Demonstration, or Deductive Argumentation. Its procedure is best learned from Book I of Euclid’s Elements, a masterpiece which in real insight is far superior to Aristotle’s Analytics; and its numerous fallacies render it all the more instructive to a close student. …

The purpose of Deduction, that of collecting consequents of the hypothesis, having been sufficiently carried out, the inquiry enters upon its Third Stage …

CP 6.470-472
‘Deduction’ (pub. 02.02.13-12:57). Quote in M. Bergman & S. Paavola (Eds.), The Commens Dictionary: Peirce's Terms in His Own Words. New Edition. Retrieved from
Feb 02, 2013, 12:57 by Sami Paavola
Last revised: 
Jan 07, 2014, 01:00 by Commens Admin