Combining Texts

Ideas for 'works (all lost)', 'The Theory of Logical Types' and 'Aboutness'

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3 ideas

5. Theory of Logic / E. Structures of Logic / 5. Functions in Logic
'Propositional functions' are ambiguous until the variable is given a value [Russell]
     Full Idea: By a 'propositional function' I mean something which contains a variable x, and expresses a proposition as soon as a value is assigned to x. That is to say, it differs from a proposition solely by the fact that it is ambiguous.
     From: Bertrand Russell (The Theory of Logical Types [1910], p.216)
     A reaction: This is Frege's notion of a 'concept', as an assertion of a predicate which still lacks a subject.
5. Theory of Logic / F. Referring in Logic / 1. Naming / e. Empty names
'Pegasus doesn't exist' is false without Pegasus, yet the absence of Pegasus is its truthmaker [Yablo]
     Full Idea: 'Pegasus does not exist' has a paradoxical, self-undermining flavour. On the one hand, the empty name makes it untrue. But now, why is the name empty? Because Pegasus does not exist. 'Pegasus does not exist' is untrue because Pegasus does not exist.
     From: Stephen Yablo (Aboutness [2014], 05.7 n20)
     A reaction: Beautiful! This is Yablo's reward for continuing to ask 'why?' after everyone else has stopped in bewilderment at the tricky phenomenon.
5. Theory of Logic / L. Paradox / 6. Paradoxes in Language / a. The Liar paradox
'All judgements made by Epimenedes are true' needs the judgements to be of the same type [Russell]
     Full Idea: Such a proposition as 'all the judgements made by Epimenedes are true' will only be prima facie capable of truth if all his judgements are of the same order.
     From: Bertrand Russell (The Theory of Logical Types [1910], p.227)
     A reaction: This is an attempt to use his theory of types to solve the Liar. Tarski's invocation of a meta-language is clearly in the same territory.