Combining Texts

Ideas for 'Material Beings', 'Logical Necessity' and 'Letters to Blijenburgh'

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8 ideas

5. Theory of Logic / B. Logical Consequence / 1. Logical Consequence
12195 Soundness in argument varies with context, and may be achieved very informally indeed [Rumfitt]
12199 There is a modal element in consequence, in assessing reasoning from suppositions [Rumfitt]
12201 We reject deductions by bad consequence, so logical consequence can't be deduction [Rumfitt]
5. Theory of Logic / D. Assumptions for Logic / 2. Excluded Middle
17587 The 'Law' of Excluded Middle needs all propositions to be definitely true or definitely false [Inwagen]
5. Theory of Logic / D. Assumptions for Logic / 3. Contradiction
12194 Contradictions include 'This is red and not coloured', as well as the formal 'B and not-B' [Rumfitt]
5. Theory of Logic / E. Structures of Logic / 4. Variables in Logic
17558 Variables are just like pronouns; syntactic explanations get muddled over dummy letters [Inwagen]
5. Theory of Logic / H. Proof Systems / 2. Axiomatic Proof
12198 Geometrical axioms in logic are nowadays replaced by inference rules (which imply the logical truths) [Rumfitt]
5. Theory of Logic / L. Paradox / 6. Paradoxes in Language / b. The Heap paradox ('Sorites')
17583 There are no heaps [Inwagen]