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Ideas for 'How the Laws of Physics Lie', 'Reason, Truth and History' and 'Lectures on Jurisprudence'

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2 ideas

5. Theory of Logic / I. Semantics of Logic / 6. Intensionalism
Intension is not meaning, as 'cube' and 'square-faced polyhedron' are intensionally the same [Putnam]
     Full Idea: Intension cannot be identified with meaning. ..'Cube' and 'regular polyhedron with six square faces' are logically equivalent predicates. The intension is the same (the function giving the cubes in any possible world) but there is a difference of meaning.
     From: Hilary Putnam (Reason, Truth and History [1981], Ch.2)
5. Theory of Logic / J. Model Theory in Logic / 2. Isomorphisms
If cats equal cherries, model theory allows reinterpretation of the whole language preserving truth [Putnam]
     Full Idea: If the number of cats happens to equal the cherries, then it follows from the theory of models that there is a reinterpretation of the entire language that leaves all sentences unchanged in truth value while permuting the extensions of 'cat' and 'cherry'.
     From: Hilary Putnam (Reason, Truth and History [1981], Ch.2)
     A reaction: This horrifying result seems to come simply from the fact that there is an isomorphism between two models, which in turn seems to rest largely on the cardinality of the models. There seems to be something wrong with model theory here (?).