creators_name: Ellerman, David creators_id: david@ellerman.org type: published_article datestamp: 2011-12-23 00:46:59 lastmod: 2011-12-23 00:46:59 metadata_visibility: show title: Counting Distinctions: On the Conceptual Foundations of Shannon's Information Theory subjects: computation-information subjects: history-of-philosophy-of-science subjects: mathematics subjects: probability-statistics full_text_status: public keywords: logical entropy, distinctions, Shannon entropy, logical information theory abstract: 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." date: 2009-05 date_type: published publication: Synthese volume: 168 number: 1 publisher: Springer (Springer Science+Business Media B.V.) pagerange: 119-149 issn: 1573-0964 related_url_url: http://www.ellerman.org/Davids-Stuff/Maths/Counting-Dits-reprint.pdf related_url_type: author citation: Ellerman, David (2009) Counting Distinctions: On the Conceptual Foundations of Shannon's Information Theory. [Published Article] document_url: http://philsci-archive.pitt.edu/8967/1/Counting%2DDistinctions%2D3.pdf