Combining Texts

All the ideas for 'Through the Looking Glass', 'Ontological Relativity' and 'Logical Necessity'

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19 ideas

4. Formal Logic / D. Modal Logic ML / 3. Modal Logic Systems / h. System S5
The logic of metaphysical necessity is S5 [Rumfitt]
5. Theory of Logic / B. Logical Consequence / 1. Logical Consequence
Soundness in argument varies with context, and may be achieved very informally indeed [Rumfitt]
There is a modal element in consequence, in assessing reasoning from suppositions [Rumfitt]
We reject deductions by bad consequence, so logical consequence can't be deduction [Rumfitt]
5. Theory of Logic / D. Assumptions for Logic / 3. Contradiction
Contradictions include 'This is red and not coloured', as well as the formal 'B and not-B' [Rumfitt]
5. Theory of Logic / G. Quantification / 4. Substitutional Quantification
If quantification is all substitutional, there is no ontology [Quine]
5. Theory of Logic / H. Proof Systems / 2. Axiomatic Proof
Geometrical axioms in logic are nowadays replaced by inference rules (which imply the logical truths) [Rumfitt]
7. Existence / A. Nature of Existence / 3. Being / e. Being and nothing
I only wish I had such eyes as to see Nobody! It's as much as I can do to see real people. [Carroll,L]
7. Existence / A. Nature of Existence / 6. Criterion for Existence
Absolute ontological questions are meaningless, because the answers are circular definitions [Quine]
7. Existence / D. Theories of Reality / 11. Ontological Commitment / d. Commitment of theories
Ontology is relative to both a background theory and a translation manual [Quine]
9. Objects / F. Identity among Objects / 1. Concept of Identity
We know what things are by distinguishing them, so identity is part of ontology [Quine]
10. Modality / A. Necessity / 3. Types of Necessity
A distinctive type of necessity is found in logical consequence [Rumfitt, by Hale/Hoffmann,A]
10. Modality / A. Necessity / 6. Logical Necessity
Logical necessity is when 'necessarily A' implies 'not-A is contradictory' [Rumfitt]
A logically necessary statement need not be a priori, as it could be unknowable [Rumfitt]
Narrow non-modal logical necessity may be metaphysical, but real logical necessity is not [Rumfitt]
10. Modality / E. Possible worlds / 1. Possible Worlds / e. Against possible worlds
If a world is a fully determinate way things could have been, can anyone consider such a thing? [Rumfitt]
13. Knowledge Criteria / E. Relativism / 5. Language Relativism
Two things are relative - the background theory, and translating the object theory into the background theory [Quine]
19. Language / B. Reference / 1. Reference theories
Reference is inscrutable, because we cannot choose between theories of numbers [Quine, by Orenstein]
19. Language / F. Communication / 6. Interpreting Language / b. Indeterminate translation
Indeterminacy translating 'rabbit' depends on translating individuation terms [Quine]