The Commens Dictionary

Quote from ‘A Theory of Probable Inference’


Corresponding to induction, we have the following mode of inference: [—]


M has, for example, the numerous marks P’, P”, P”’, etc.,
S has the proportion r of the marks P’, P”, P”’, etc.;
Hence, probably and approximately, S has an r-likeness to M.

Thus, we know, that the ancient Mound-builders of North America present, in all those respects in which we have been able to make the comparison, a limited degree of resemblance with the Pueblo Indians. The inference is, then, that in all respects there is about the same degree of resemblance between these races.

If I am permitted the extended sense which I have given to the word “induction,” this argument is simply an induction respecting qualities instead of respecting things. [—]

I call this induction of characters hypothetic inference, or, briefly, hypothesis.

CP 2.706-707
‘Hypothesis [as a form of reasoning]’ (pub. 03.02.13-17:33). Quote in M. Bergman & S. Paavola (Eds.), The Commens Dictionary: Peirce's Terms in His Own Words. New Edition. Retrieved from
Feb 03, 2013, 17:33 by Sami Paavola
Last revised: 
Jan 07, 2014, 01:00 by Commens Admin