Combining Texts

All the ideas for 'works', 'First-Order Modal Logic' and 'works'

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75 ideas

1. Philosophy / A. Wisdom / 1. Nature of Wisdom
23890 For Plato true wisdom is supernatural [Plato, by Weil]
1. Philosophy / C. History of Philosophy / 2. Ancient Philosophy / b. Pre-Socratic philosophy
3060 Plato never mentions Democritus, and wished to burn his books [Plato, by Diog. Laertius]
2. Reason / C. Styles of Reason / 1. Dialectic
23891 Two contradictories force us to find a relation which will correlate them [Plato, by Weil]
4. Formal Logic / B. Propositional Logic PL / 3. Truth Tables
9738 Each line of a truth table is a model [Fitting/Mendelsohn]
4. Formal Logic / D. Modal Logic ML / 2. Tools of Modal Logic / a. Symbols of ML
9727 Modal logic adds □ (necessarily) and ◊ (possibly) to classical logic [Fitting/Mendelsohn]
9726 We let 'R' be the accessibility relation: xRy is read 'y is accessible from x' [Fitting/Mendelsohn]
9737 The symbol ||- is the 'forcing' relation; 'Γ ||- P' means that P is true in world Γ [Fitting/Mendelsohn]
13136 The prefix σ names a possible world, and σ.n names a world accessible from that one [Fitting/Mendelsohn]
4. Formal Logic / D. Modal Logic ML / 2. Tools of Modal Logic / b. Terminology of ML
13727 A 'constant' domain is the same for all worlds; 'varying' domains can be entirely separate [Fitting/Mendelsohn]
9734 Modern modal logic introduces 'accessibility', saying xRy means 'y is accessible from x' [Fitting/Mendelsohn]
9736 A 'model' is a frame plus specification of propositions true at worlds, written < G,R,||- > [Fitting/Mendelsohn]
9735 A 'frame' is a set G of possible worlds, with an accessibility relation R, written < G,R > [Fitting/Mendelsohn]
9741 Accessibility relations can be 'reflexive' (self-referring), 'transitive' (carries over), or 'symmetric' (mutual) [Fitting/Mendelsohn]
4. Formal Logic / D. Modal Logic ML / 2. Tools of Modal Logic / c. Derivation rules of ML
13149 S5: a) if n ◊X then kX b) if n ¬□X then k ¬X c) if n □X then k X d) if n ¬◊X then k ¬X [Fitting/Mendelsohn]
13141 Negation: if σ ¬¬X then σ X [Fitting/Mendelsohn]
13138 Disj: a) if σ ¬(X∨Y) then σ ¬X and σ ¬Y b) if σ X∨Y then σ X or σ Y [Fitting/Mendelsohn]
13142 Existential: a) if σ ◊X then σ.n X b) if σ ¬□X then σ.n ¬X [n is new] [Fitting/Mendelsohn]
13144 T reflexive: a) if σ □X then σ X b) if σ ¬◊X then σ ¬X [Fitting/Mendelsohn]
13145 D serial: a) if σ □X then σ ◊X b) if σ ¬◊X then σ ¬□X [Fitting/Mendelsohn]
13146 B symmetric: a) if σ.n □X then σ X b) if σ.n ¬◊X then σ ¬X [n occurs] [Fitting/Mendelsohn]
13147 4 transitive: a) if σ □X then σ.n □X b) if σ ¬◊X then σ.n ¬◊X [n occurs] [Fitting/Mendelsohn]
13148 4r rev-trans: a) if σ.n □X then σ □X b) if σ.n ¬◊X then σ ¬◊X [n occurs] [Fitting/Mendelsohn]
9740 If a proposition is possibly true in a world, it is true in some world accessible from that world [Fitting/Mendelsohn]
9739 If a proposition is necessarily true in a world, it is true in all worlds accessible from that world [Fitting/Mendelsohn]
13137 Conj: a) if σ X∧Y then σ X and σ Y b) if σ ¬(X∧Y) then σ ¬X or σ ¬Y [Fitting/Mendelsohn]
13140 Bicon: a)if σ(X↔Y) then σ(X→Y) and σ(Y→X) b) [not biconditional, one or other fails] [Fitting/Mendelsohn]
13139 Implic: a) if σ ¬(X→Y) then σ X and σ ¬Y b) if σ X→Y then σ ¬X or σ Y [Fitting/Mendelsohn]
13143 Universal: a) if σ ¬◊X then σ.m ¬X b) if σ □X then σ.m X [m exists] [Fitting/Mendelsohn]
4. Formal Logic / D. Modal Logic ML / 3. Modal Logic Systems / b. System K
9742 The system K has no accessibility conditions [Fitting/Mendelsohn]
4. Formal Logic / D. Modal Logic ML / 3. Modal Logic Systems / c. System D
13114 □P → P is not valid in D (Deontic Logic), since an obligatory action may be not performed [Fitting/Mendelsohn]
9743 The system D has the 'serial' conditon imposed on its accessibility relation [Fitting/Mendelsohn]
4. Formal Logic / D. Modal Logic ML / 3. Modal Logic Systems / d. System T
9744 The system T has the 'reflexive' conditon imposed on its accessibility relation [Fitting/Mendelsohn]
4. Formal Logic / D. Modal Logic ML / 3. Modal Logic Systems / e. System K4
9746 The system K4 has the 'transitive' condition on its accessibility relation [Fitting/Mendelsohn]
4. Formal Logic / D. Modal Logic ML / 3. Modal Logic Systems / f. System B
9745 The system B has the 'reflexive' and 'symmetric' conditions on its accessibility relation [Fitting/Mendelsohn]
4. Formal Logic / D. Modal Logic ML / 3. Modal Logic Systems / g. System S4
9747 The system S4 has the 'reflexive' and 'transitive' conditions on its accessibility relation [Fitting/Mendelsohn]
4. Formal Logic / D. Modal Logic ML / 3. Modal Logic Systems / h. System S5
9748 System S5 has the 'reflexive', 'symmetric' and 'transitive' conditions on its accessibility relation [Fitting/Mendelsohn]
4. Formal Logic / D. Modal Logic ML / 4. Alethic Modal Logic
9404 Modality affects content, because P→◊P is valid, but ◊P→P isn't [Fitting/Mendelsohn]
4. Formal Logic / D. Modal Logic ML / 5. Epistemic Logic
13112 In epistemic logic knowers are logically omniscient, so they know that they know [Fitting/Mendelsohn]
13111 Read epistemic box as 'a knows/believes P' and diamond as 'for all a knows/believes, P' [Fitting/Mendelsohn]
4. Formal Logic / D. Modal Logic ML / 6. Temporal Logic
13113 F: will sometime, P: was sometime, G: will always, H: was always [Fitting/Mendelsohn]
4. Formal Logic / D. Modal Logic ML / 7. Barcan Formula
13728 The Barcan says nothing comes into existence; the Converse says nothing ceases; the pair imply stability [Fitting/Mendelsohn]
13729 The Barcan corresponds to anti-monotonicity, and the Converse to monotonicity [Fitting/Mendelsohn]
5. Theory of Logic / F. Referring in Logic / 3. Property (λ-) Abstraction
9725 'Predicate abstraction' abstracts predicates from formulae, giving scope for constants and functions [Fitting/Mendelsohn]
8. Modes of Existence / A. Relations / 3. Structural Relations
14502 Plato's idea of 'structure' tends to be mathematically expressed [Plato, by Koslicki]
8. Modes of Existence / D. Universals / 6. Platonic Forms / a. Platonic Forms
17948 Plato's Forms meant that the sophists only taught the appearance of wisdom and virtue [Plato, by Nehamas]
3039 When Diogenes said he could only see objects but not their forms, Plato said it was because he had eyes but no intellect [Plato, by Diog. Laertius]
20906 Platonists argue for the indivisible triangle-in-itself [Plato, by Aristotle]
8. Modes of Existence / D. Universals / 6. Platonic Forms / b. Partaking
556 If there is one Form for both the Form and its participants, they must have something in common [Aristotle on Plato]
8. Modes of Existence / D. Universals / 6. Platonic Forms / c. Self-predication
563 If gods are like men, they are just eternal men; similarly, Forms must differ from particulars [Aristotle on Plato]
8. Modes of Existence / D. Universals / 6. Platonic Forms / d. Forms critiques
557 A Form is a cause of things only in the way that white mixed with white is a cause [Aristotle on Plato]
565 The Forms cannot be changeless if they are in changing things [Aristotle on Plato]
9. Objects / A. Existence of Objects / 2. Abstract Objects / a. Nature of abstracta
9607 The greatest discovery in human thought is Plato's discovery of abstract objects [Brown,JR on Plato]
9. Objects / A. Existence of Objects / 5. Individuation / a. Individuation
13263 We can grasp whole things in science, because they have a mathematics and a teleology [Plato, by Koslicki]
9. Objects / B. Unity of Objects / 1. Unifying an Object / a. Intrinsic unification
13261 Plato sees an object's structure as expressible in mathematics [Plato, by Koslicki]
13265 Plato was less concerned than Aristotle with the source of unity in a complex object [Plato, by Koslicki]
9. Objects / B. Unity of Objects / 2. Substance / c. Types of substance
593 Plato's holds that there are three substances: Forms, mathematical entities, and perceptible bodies [Plato, by Aristotle]
9. Objects / C. Structure of Objects / 8. Parts of Objects / c. Wholes from parts
13260 Plato says wholes are either containers, or they're atomic, or they don't exist [Plato, by Koslicki]
9. Objects / D. Essence of Objects / 2. Types of Essence
11237 Only universals have essence [Plato, by Politis]
9. Objects / D. Essence of Objects / 6. Essence as Unifier
11238 Plato and Aristotle take essence to make a thing what it is [Plato, by Politis]
9. Objects / F. Identity among Objects / 7. Indiscernible Objects
13730 The Indiscernibility of Identicals has been a big problem for modal logic [Fitting/Mendelsohn]
10. Modality / E. Possible worlds / 3. Transworld Objects / a. Transworld identity
13725 □ must be sensitive as to whether it picks out an object by essential or by contingent properties [Fitting/Mendelsohn]
13731 Objects retain their possible properties across worlds, so a bundle theory of them seems best [Fitting/Mendelsohn]
10. Modality / E. Possible worlds / 3. Transworld Objects / c. Counterparts
13726 Counterpart relations are neither symmetric nor transitive, so there is no logic of equality for them [Fitting/Mendelsohn]
14. Science / D. Explanation / 1. Explanation / b. Aims of explanation
17085 A good explanation totally rules out the opposite explanation (so Forms are required) [Plato, by Ruben]
18. Thought / A. Modes of Thought / 3. Emotions / g. Controlling emotions
1651 Plato wanted to somehow control and purify the passions [Vlastos on Plato]
19. Language / F. Communication / 1. Rhetoric
3324 Plato's whole philosophy may be based on being duped by reification - a figure of speech [Benardete,JA on Plato]
21. Aesthetics / B. Nature of Art / 4. Art as Expression
8120 Objects can be beautiful which express nothing at all, such as the rainbow [Herbart, by Tolstoy]
22. Metaethics / A. Ethics Foundations / 2. Source of Ethics / c. Ethical intuitionism
7503 Plato never refers to examining the conscience [Plato, by Foucault]
22. Metaethics / A. Ethics Foundations / 2. Source of Ethics / j. Ethics by convention
2173 As religion and convention collapsed, Plato sought morals not just in knowledge, but in the soul [Williams,B on Plato]
22. Metaethics / C. The Good / 1. Goodness / b. Types of good
9274 Plato's legacy to European thought was the Good, the Beautiful and the True [Plato, by Gray]
22. Metaethics / C. The Good / 1. Goodness / f. Good as pleasure
94 Pleasure is better with the addition of intelligence, so pleasure is not the good [Plato, by Aristotle]
22. Metaethics / C. The Good / 2. Happiness / d. Routes to happiness
17947 Plato decided that the virtuous and happy life was the philosophical life [Plato, by Nehamas]
23. Ethics / C. Virtue Theory / 1. Virtue Theory / a. Nature of virtue
6015 Plato, unusually, said that theoretical and practical wisdom are inseparable [Plato, by Kraut]
23. Ethics / F. Existentialism / 4. Boredom
2912 Plato is boring [Nietzsche on Plato]
27. Natural Reality / D. Time / 3. Parts of Time / a. Beginning of time
1526 Almost everyone except Plato thinks that time could not have been generated [Plato, by Aristotle]