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Ideas for 'System of Logic', 'Relativism' and 'An Analysis of Knowledge and Valuation'

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7 ideas

5. Theory of Logic / A. Overview of Logic / 6. Classical Logic
Logical relativism appears if we allow more than one legitimate logical system [O'Grady]
     Full Idea: Logical relativism emerges if one defends the existence of two or more rival systems that one may legitimately choose between, or move back and forth between.
     From: Paul O'Grady (Relativism [2002], Ch.2)
     A reaction: All my instincts rebel against this possibility. All of Aristotle's and Kant's philosophy would be rendered meaningless. Obviously you can create artificial logics (like games), but I believe there is a truth logic. (Pathetic, isn't it?)
5. Theory of Logic / D. Assumptions for Logic / 1. Bivalence
A third value for truth might be "indeterminate", or a point on a scale between 'true' and 'false' [O'Grady]
     Full Idea: Suggestions for a third value for truth are "indeterminate", or a scale running from "true", through "mostly true", "mainly true", "half true", "mainly false", "mostly false", to "false", or maybe even "0.56 true".
     From: Paul O'Grady (Relativism [2002], Ch.2)
     A reaction: Anything on a sliding scale sounds wrong, as it seems to be paracitic on an underlying fixed idea of 'true'. "Indeterminate", though, seems just right for the truth of predictions ('sea-fight tomorrow').
5. Theory of Logic / E. Structures of Logic / 2. Logical Connectives / a. Logical connectives
Wittgenstein reduced Russell's five primitive logical symbols to a mere one [O'Grady]
     Full Idea: While Russell and Whitehead used five primitive logical symbols in their system, Wittgenstein suggested in his 'Tractatus' that this be reduced to one.
     From: Paul O'Grady (Relativism [2002], Ch.2)
     A reaction: This certainly captures why Russell was so impressed by him. In retrospect what looked like progress presumably now looks like the beginning of the collapse of the enterprise.
5. Theory of Logic / E. Structures of Logic / 2. Logical Connectives / d. and
Combining two distinct assertions does not necessarily lead to a single 'complex proposition' [Mill]
     Full Idea: In 'Caesar is dead, and Brutus is alive' ...there are here two distinct assertions; and we might as well call a street a complex house, as these two propositions a complex proposition.
     From: John Stuart Mill (System of Logic [1843], 1.04.3)
     A reaction: Arthur Prior, in his article on 'tonk', cites this to claim that the mere account of the and-introduction rule does not guarantee the existence of any conjunctive proposition that can result from it. Mill says you are adding a third proposition.
5. Theory of Logic / F. Referring in Logic / 1. Naming / a. Names
All names are names of something, real or imaginary [Mill]
     Full Idea: All names are names of something, real or imaginary.
     From: John Stuart Mill (System of Logic [1843], p.32), quoted by Mark Sainsbury - The Essence of Reference 18.2
     A reaction: Mill's example of of being like a chalk mark on a door, but Sainsbury points out that names can be detached from bearers in a way that chalk marks can't.
5. Theory of Logic / F. Referring in Logic / 1. Naming / c. Names as referential
Mill says names have denotation but not connotation [Mill, by Kripke]
     Full Idea: It is a well known doctrine of Mill that names have denotation but not connotation.
     From: report of John Stuart Mill (System of Logic [1843]) by Saul A. Kripke - Naming and Necessity lectures Lecture 1
     A reaction: A nice starting point for any discussion of the topic. The obvious response is that a name like 'Attila the Hun' seems to have a very vague denotation for most of us, but a rather powerful connotation.
Proper names are just labels for persons or objects, and the meaning is the object [Mill, by Lycan]
     Full Idea: Mill seemed to defend the view that proper names are merely labels for individual persons or objects, and contribute no more than those individuals themselves to the meanings of sentences in which they occur.
     From: report of John Stuart Mill (System of Logic [1843]) by William Lycan - Philosophy of Language
     A reaction: Identity statements can become trivial on this view ('Twain is Clemens'). Modern views have become more sympathetic to Mill, since externalism places meanings outside the head of the speaker.