Combining Texts

Ideas for 'Parmenides', 'Rationality and Logic' and 'works'

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3 ideas

5. Theory of Logic / A. Overview of Logic / 4. Pure Logic
There is no clear boundary between the logical and the non-logical [Tarski]
     Full Idea: No objective grounds are known to me which permit us to draw a sharp boundary between the two groups of terms, the logical and the non-logical.
     From: Alfred Tarski (works [1936]), quoted by Alan Musgrave - Logicism Revisited §3
     A reaction: Musgrave is pointing out that this is bad news if you want to 'reduce' something like arithmetic to logic. 'Logic' is a vague object.
Logic is explanatorily and ontologically dependent on rational animals [Hanna]
     Full Idea: Logic is explanatorily and ontologically dependent on rational animals.
     From: Robert Hanna (Rationality and Logic [2006], 1.6)
     A reaction: This is a splendid defiance of the standard Fregean view of logic as having an inner validity of its own, having nothing to do with the psychology of thinkers. But if Hanna is right, why does logical consequence seem to be necessary?
Logic is personal and variable, but it has a universal core [Hanna]
     Full Idea: Beyond an innate and thus universally share protologic, each reasoner's mental logic is only more or less similar to the mental logic of any other reasoner.
     From: Robert Hanna (Rationality and Logic [2006], 5.7)
     A reaction: This is the main thesis of Hanna's book. I like the combination of this idea with Stephen Read's remark that each student should work out a personal logic which has their own private endorsement.