Counting Distinctions: On the Conceptual Foundations of Shannon's Information Theory

Citation data:

Synthese, ISSN: 1573-0964, Vol: 168, Issue: 1, Page: 119-149

Publication Year:
2009
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Repository URL:
http://philsci-archive.pitt.edu/id/eprint/8967
Author(s):
Ellerman, David
Publisher(s):
Springer (Springer Science+Business Media B.V.)
article description
Categorical logic has shown that modern logic is essentially the logic of subsets (or "subobjects"). Partitions are dual to subsets so there is a dual logic of partitions where a "distinction" [an ordered pair of distinct elements (u,u′) from the universe U ] is dual to an "element". An element being in a subset is analogous to a partition π on U making a distinction, i.e., if u and u′ were in different blocks of π. Subset logic leads to finite probability theory by taking the (Laplacian) probability as the normalized size of each subset-event of a finite universe. The analogous step in the logic of partitions is to assign to a partition the number of distinctions made by a partition normalized by the total number of ordered pairs |U|² from the finite universe. That yields a notion of "logical entropy" for partitions and a "logical information theory." The logical theory directly counts the (normalized) number of distinctions in a partition while Shannon's theory gives the average number of binary partitions needed to make those same distinctions. Thus the logical theory is seen as providing a conceptual underpinning for Shannon's theory based on the logical notion of "distinctions."