{ Information = Comprehension × Extension } • Comment 8

So what is all this fuss about the relation between inquiry and signs, as analyzed in Peirce’s theories of their structure and function and synthesized in his theory of information?

The best way I’ve found to see where the problem lies is to run through a series of concrete examples of the sort Peirce used to illustrate his notions of information, inquiry, and signs, examples just complex enough to show the interplay of main ideas.

There is an enlightening set of examples in Peirce’s early lectures on the Logic of Science.  Here is the blog post I wrote to set up their discussion:

Another angle from which to approach the incidence of signs and inquiry is by way of C.S. Peirce’s “laws of information” and the corresponding theory of information he developed from the time of his lectures on the “Logic of Science” at Harvard University (1865) and the Lowell Institute (1866).

When it comes to the supposed reciprocity between extensions and intensions, Peirce, of course, has another idea, and I would say a better idea, partly because it forms the occasion for him to bring in his new-fangled notion of “information” to mediate the otherwise static dualism between the other two.  The development of this novel idea brings Peirce to enunciate the formula:

\mathrm{Information} = \mathrm{Comprehension} \times \mathrm{Extension}

But comprehending what in the world that might mean is a much longer story, the end of which your present teller has yet to reach.  So, this time around, I will take up the story near the end of the beginning of Peirce’s own telling of it, for no better reason than that’s where I myself initially came in, or, at least, where it all started making any kind of sense to me.  And from this point we will find it easy enough to flash both backward and forward, to and fro, as the occasions arise for doing so.


  • Peirce, C.S. (1866), “The Logic of Science, or, Induction and Hypothesis”, Lowell Lectures of 1866, pp. 357–504 in Writings of Charles S. Peirce : A Chronological Edition, Volume 1, 1857–1866, Peirce Edition Project, Indiana University Press, Bloomington, IN, 1982.


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This entry was posted in Abduction, Belief Fixation, C.S. Peirce, Comprehension, Deduction, Extension, Hypothesis, Icon Index Symbol, Induction, Inference, Information, Information = Comprehension × Extension, Inquiry, Intension, Logic, Logic of Science, Peirce, Peirce's Categories, Pragmatism, Scientific Method, Semiotic Information, Semiotics, Sign Relations and tagged , , , , , , , , , , , , , , , , , , , , , , . Bookmark the permalink.

3 Responses to { Information = Comprehension × Extension } • Comment 8

  1. Pingback: Survey of Pragmatic Semiotic Information • 4 | Inquiry Into Inquiry

  2. Pingback: Survey of Semiotic Theory Of Information • 3 | Inquiry Into Inquiry

  3. Pingback: Survey of Pragmatic Semiotic Information • 5 | Inquiry Into Inquiry

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