8942
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Lukasiewicz's L3 logic has three truth-values, T, F and I (for 'indeterminate') [Lukasiewicz, by Fisher]
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Full Idea:
In response to Aristotle's sea-battle problem, Lukasiewicz proposed a three-valued logic that has come to be known as L3. In addition to the values true and false (T and F), there is a third truth-value, I, meaning 'indeterminate' or 'possible'.
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From:
report of Jan Lukasiewicz (Elements of Mathematical Logic [1928], 7.I) by Jennifer Fisher - On the Philosophy of Logic
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A reaction:
[He originated the idea in 1917] In what sense is the third value a 'truth' value? Is 'I don't care' a truth-value? Or 'none of the above'? His idea means that formalization doesn't collapse when things get obscure. You park a few propositions under I.
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13231
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Explanatory proofs rest on 'characterizing properties' of entities or structure [Steiner,M]
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Full Idea:
My proposal is that an explanatory proof makes reference to the 'characterizing property' of an entity or structure mentioned in the theorem, where the proof depends on the property. If we substitute a different object, the theory collapses.
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From:
Mark Steiner (Mathematical Explanation [1978], p.34)
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A reaction:
He prefers 'characterizing property' to 'essence', because he is not talking about necessary properties, since all properties are necessary in mathematics. He is, in fact, reverting to the older notion of an essence, as the core power of the thing.
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15877
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The aim of science is just to create a comprehensive, elegant language to describe brute facts [Poincaré, by Harré]
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Full Idea:
In Poincaré's view, we try to construct a language within which the brute facts of experience are expressed as comprehensively and as elegantly as possible. The job of science is the forging of a language precisely suited to that purpose.
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From:
report of Henri Poincaré (The Value of Science [1906], Pt III) by Rom Harré - Laws of Nature 2
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A reaction:
I'm often struck by how obscure and difficult our accounts of self-evident facts can be. Chairs are easy, and the metaphysics of chairs is hideous. Why is that? I'm a robust realist, but I like Poincaré's idea. He permits facts.
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