Combining Texts

All the ideas for 'The Nature of Things', 'Philosophical Logic' and 'Letter to Menoeceus'

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50 ideas

1. Philosophy / D. Nature of Philosophy / 2. Invocation to Philosophy
14052 Begin philosophy when you are young, and keep going when you are old [Epicurus]
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]
15421 Classical logic neglects counterfactuals, temporality and modality, because maths doesn't use them [Burgess]
15427 The Cut Rule expresses the classical idea that entailment is transitive [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
15426 We can build one expanding sequence, instead of a chain of deductions [Burgess]
15425 The sequent calculus makes it possible to have proof without transitivity of entailment [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
15411 We only need to study mathematical models, since all other models are isomorphic to these [Burgess]
15412 Models leave out meaning, and just focus on truth values [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
15417 Logical necessity has two sides - validity and demonstrability - which coincide in classical logic [Burgess]
15419 General consensus is S5 for logical modality of validity, and S4 for proof [Burgess]
10. Modality / B. Possibility / 8. Conditionals / a. Conditionals
15423 It is doubtful whether the negation of a conditional has any clear meaning [Burgess]
15422 Three conditionals theories: Materialism (material conditional), Idealism (true=assertable), Nihilism (no truth) [Burgess]
16. Persons / F. Free Will / 6. Determinism / b. Fate
14062 Sooner follow mythology, than accept the 'fate' of natural philosophers [Epicurus]
16. Persons / F. Free Will / 7. Compatibilism
1837 We should not refer things to irresponsible necessity, but either to fortune or to our own will [Epicurus]
20. Action / C. Motives for Action / 3. Acting on Reason / a. Practical reason
1836 Prudence is more valuable than philosophy, because it avoids confusions of the soul [Epicurus]
20. Action / C. Motives for Action / 4. Responsibility for Actions
14061 Our own choices are autonomous, and the basis for praise and blame [Epicurus]
22. Metaethics / B. Value / 2. Values / e. Death
14053 It is absurd to fear the pain of death when you are not even facing it [Epicurus]
14055 The wisdom that produces a good life also produces a good death [Epicurus]
14054 Fearing death is absurd, because we are not present when it occurs [Epicurus]
22. Metaethics / C. The Good / 1. Goodness / f. Good as pleasure
14058 Pleasure is the goal, but as lack of pain and calm mind, not as depraved or greedy pleasure [Epicurus]
1833 Pleasure is the first good in life [Epicurus]
14057 All pleasures are good, but it is not always right to choose them [Epicurus]
22. Metaethics / C. The Good / 1. Goodness / i. Moral luck
14063 Sooner a good decision going wrong, than a bad one turning out for the good [Epicurus]
22. Metaethics / C. The Good / 2. Happiness / d. Routes to happiness
14059 The best life is not sensuality, but rational choice and healthy opinion [Epicurus]
22. Metaethics / C. The Good / 3. Pleasure / a. Nature of pleasure
1835 True pleasure is not debauchery, but freedom from physical and mental pain [Epicurus]
22. Metaethics / C. The Good / 3. Pleasure / c. Value of pleasure
14056 We only need pleasure when we have the pain of desire [Epicurus]
23. Ethics / C. Virtue Theory / 1. Virtue Theory / b. Basis of virtue
14060 Prudence is the greatest good, and more valuable than philosophy, because it produces virtue [Epicurus]