Combining Texts

All the ideas for 'Introduction to Russell's Theory of Types', 'The Case against Closure (and reply)' and 'The Concept of Logical Consequence'

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12 ideas

4. Formal Logic / F. Set Theory ST / 4. Axioms for Sets / p. Axiom of Reducibility
The Axiom of Reducibility is self-effacing: if true, it isn't needed [Quine]
5. Theory of Logic / B. Logical Consequence / 1. Logical Consequence
Split out the logical vocabulary, make an assignment to the rest. It's logical if premises and conclusion match [Tarski, by Rumfitt]
5. Theory of Logic / B. Logical Consequence / 4. Semantic Consequence |=
X follows from sentences K iff every model of K also models X [Tarski]
5. Theory of Logic / J. Model Theory in Logic / 1. Logical Models
A 'model' is a sequence of objects which satisfies a complete set of sentential functions [Tarski]
13. Knowledge Criteria / A. Justification Problems / 2. Justification Challenges / c. Knowledge closure
Closure says if you know P, and also know P implies Q, then you must know Q [Dretske]
We needn't regret the implications of our regrets; regretting drinking too much implies the past is real [Dretske]
Reasons for believing P may not transmit to its implication, Q [Dretske]
Knowing by visual perception is not the same as knowing by implication [Dretske]
The only way to preserve our homely truths is to abandon closure [Dretske]
P may imply Q, but evidence for P doesn't imply evidence for Q, so closure fails [Dretske]
We know past events by memory, but we don't know the past is real (an implication) by memory [Dretske]
19. Language / E. Analyticity / 1. Analytic Propositions
Sentences are 'analytical' if every sequence of objects models them [Tarski]