The Commens Dictionary

Quote from ‘Harvard Lectures on Pragmatism: Lecture VI’


Abduction is the process of forming an explanatory hypothesis. It is the only logical operation which introduces any new idea; for induction does nothing but determine a value, and deduction merely evolves the necessary consequences of a pure hypothesis.

Deduction proves that something must be; Induction shows that something actually is operative; Abduction merely suggests that something may be.

Its only justification is that from its suggestion deduction can draw a prediction which can be tested by induction, and that, if we are ever to learn anything or to understand phenomena at all, it must be by that this is to be brought about.

CP 5.171
‘Induction’ (pub. 02.02.13-10:26). Quote in M. Bergman & S. Paavola (Eds.), The Commens Dictionary: Peirce's Terms in His Own Words. New Edition. Retrieved from
Feb 02, 2013, 10:26 by Sami Paavola
Last revised: 
Jan 07, 2014, 01:00 by Commens Admin