Combining Texts

All the ideas for 'The Nature of Things', 'Philosophical Logic' and 'Mirror Mirror - Is That All?'

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42 ideas

1. Philosophy / D. Nature of Philosophy / 5. Aims of Philosophy / a. Philosophy as worldly
9327 Organisms understand their worlds better if they understand themselves [Gulick]
4. Formal Logic / D. Modal Logic ML / 6. Temporal Logic
15413 With four tense operators, all complex tenses reduce to fourteen basic cases [Burgess]
4. Formal Logic / D. Modal Logic ML / 7. Barcan Formula
15415 The temporal Barcan formulas fix what exists, which seems absurd [Burgess]
4. Formal Logic / E. Nonclassical Logics / 2. Intuitionist Logic
15430 Is classical logic a part of intuitionist logic, or vice versa? [Burgess]
15431 It is still unsettled whether standard intuitionist logic is complete [Burgess]
4. Formal Logic / E. Nonclassical Logics / 5. Relevant Logic
15429 Relevance logic's → is perhaps expressible by 'if A, then B, for that reason' [Burgess]
4. Formal Logic / F. Set Theory ST / 7. Natural Sets
9406 A class is natural when everybody can spot further members of it [Quinton]
5. Theory of Logic / A. Overview of Logic / 4. Pure Logic
15404 Technical people see logic as any formal system that can be studied, not a study of argument validity [Burgess]
5. Theory of Logic / A. Overview of Logic / 6. Classical Logic
15405 Classical logic neglects the non-mathematical, such as temporality or modality [Burgess]
15427 The Cut Rule expresses the classical idea that entailment is transitive [Burgess]
15421 Classical logic neglects counterfactuals, temporality and modality, because maths doesn't use them [Burgess]
5. Theory of Logic / A. Overview of Logic / 9. Philosophical Logic
15403 Philosophical logic is a branch of logic, and is now centred in computer science [Burgess]
5. Theory of Logic / E. Structures of Logic / 2. Logical Connectives / a. Logical connectives
15407 Formalising arguments favours lots of connectives; proving things favours having very few [Burgess]
5. Theory of Logic / E. Structures of Logic / 2. Logical Connectives / e. or
15424 Asserting a disjunction from one disjunct seems odd, but can be sensible, and needed in maths [Burgess]
5. Theory of Logic / E. Structures of Logic / 4. Variables in Logic
15409 All occurrences of variables in atomic formulas are free [Burgess]
5. Theory of Logic / F. Referring in Logic / 2. Descriptions / b. Definite descriptions
15414 The denotation of a definite description is flexible, rather than rigid [Burgess]
5. Theory of Logic / H. Proof Systems / 1. Proof Systems
15406 'Induction' and 'recursion' on complexity prove by connecting a formula to its atomic components [Burgess]
5. Theory of Logic / H. Proof Systems / 6. Sequent Calculi
15425 The sequent calculus makes it possible to have proof without transitivity of entailment [Burgess]
15426 We can build one expanding sequence, instead of a chain of deductions [Burgess]
5. Theory of Logic / I. Semantics of Logic / 3. Logical Truth
15408 'Tautologies' are valid formulas of classical sentential logic - or substitution instances in other logics [Burgess]
5. Theory of Logic / I. Semantics of Logic / 4. Satisfaction
15418 Validity (for truth) and demonstrability (for proof) have correlates in satisfiability and consistency [Burgess]
5. Theory of Logic / J. Model Theory in Logic / 1. Logical Models
15412 Models leave out meaning, and just focus on truth values [Burgess]
15411 We only need to study mathematical models, since all other models are isomorphic to these [Burgess]
15416 We aim to get the technical notion of truth in all models matching intuitive truth in all instances [Burgess]
5. Theory of Logic / L. Paradox / 6. Paradoxes in Language / a. The Liar paradox
15428 The Liar seems like a truth-value 'gap', but dialethists see it as a 'glut' [Burgess]
7. Existence / E. Categories / 5. Category Anti-Realism
15730 Extreme nominalists say all classification is arbitrary convention [Quinton]
8. Modes of Existence / B. Properties / 5. Natural Properties
15728 The naturalness of a class depends as much on the observers as on the objects [Quinton]
9407 Properties imply natural classes which can be picked out by everybody [Quinton]
8. Modes of Existence / D. Universals / 4. Uninstantiated Universals
15729 Uninstantiated properties must be defined using the instantiated ones [Quinton]
9. Objects / A. Existence of Objects / 5. Individuation / b. Individuation by properties
8520 An individual is a union of a group of qualities and a position [Quinton, by Campbell,K]
10. Modality / A. Necessity / 4. De re / De dicto modality
15420 De re modality seems to apply to objects a concept intended for sentences [Burgess]
10. Modality / A. Necessity / 6. Logical Necessity
15419 General consensus is S5 for logical modality of validity, and S4 for proof [Burgess]
15417 Logical necessity has two sides - validity and demonstrability - which coincide in classical logic [Burgess]
10. Modality / B. Possibility / 8. Conditionals / a. Conditionals
15422 Three conditionals theories: Materialism (material conditional), Idealism (true=assertable), Nihilism (no truth) [Burgess]
15423 It is doubtful whether the negation of a conditional has any clear meaning [Burgess]
11. Knowledge Aims / A. Knowledge / 2. Understanding
9325 In contrast with knowledge, the notion of understanding emphasizes practical engagement [Gulick]
11. Knowledge Aims / A. Knowledge / 6. Knowing How
9326 Knowing-that is a much richer kind of knowing-how [Gulick]
15. Nature of Minds / B. Features of Minds / 1. Consciousness / b. Essence of consciousness
9319 Is consciousness a type of self-awareness, or is being self-aware a way of being conscious? [Gulick]
15. Nature of Minds / B. Features of Minds / 1. Consciousness / f. Higher-order thought
9320 Higher-order theories divide over whether the higher level involves thought or perception [Gulick]
9321 Higher-order models reduce the problem of consciousness to intentionality [Gulick]
9322 Maybe qualia only exist at the lower level, and a higher-level is needed for what-it-is-like [Gulick]
27. Natural Reality / G. Biology / 2. Life
9324 From the teleopragmatic perspective, life is largely an informational process [Gulick]