Combining Texts

All the ideas for 'Believing the Axioms I', 'Modality' and 'Goodbye Descartes'

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41 ideas

1. Philosophy / B. History of Ideas / 5. Later European Thought
8092 Logic was merely a branch of rhetoric until the scientific 17th century [Devlin]
2. Reason / A. Nature of Reason / 1. On Reason
5750 Consistency is modal, saying propositions are consistent if they could be true together [Melia]
4. Formal Logic / A. Syllogistic Logic / 2. Syllogistic Logic
8081 'No councillors are bankers' and 'All bankers are athletes' implies 'Some athletes are not councillors' [Devlin]
4. Formal Logic / B. Propositional Logic PL / 1. Propositional Logic
8085 Modern propositional inference replaces Aristotle's 19 syllogisms with modus ponens [Devlin]
4. Formal Logic / B. Propositional Logic PL / 2. Tools of Propositional Logic / e. Axioms of PL
8086 Predicate logic retains the axioms of propositional logic [Devlin]
4. Formal Logic / C. Predicate Calculus PC / 1. Predicate Calculus PC
5737 Predicate logic has connectives, quantifiers, variables, predicates, equality, names and brackets [Melia]
4. Formal Logic / D. Modal Logic ML / 1. Modal Logic
5744 First-order predicate calculus is extensional logic, but quantified modal logic is intensional (hence dubious) [Melia]
4. Formal Logic / F. Set Theory ST / 4. Axioms for Sets / a. Axioms for sets
13011 New axioms are being sought, to determine the size of the continuum [Maddy]
4. Formal Logic / F. Set Theory ST / 4. Axioms for Sets / b. Axiom of Extensionality I
13013 The Axiom of Extensionality seems to be analytic [Maddy]
13014 Extensional sets are clearer, simpler, unique and expressive [Maddy]
4. Formal Logic / F. Set Theory ST / 4. Axioms for Sets / f. Axiom of Infinity V
13021 The Axiom of Infinity states Cantor's breakthrough that launched modern mathematics [Maddy]
13022 Infinite sets are essential for giving an account of the real numbers [Maddy]
4. Formal Logic / F. Set Theory ST / 4. Axioms for Sets / g. Axiom of Powers VI
13023 The Power Set Axiom is needed for, and supported by, accounts of the continuum [Maddy]
4. Formal Logic / F. Set Theory ST / 4. Axioms for Sets / j. Axiom of Choice IX
13024 Efforts to prove the Axiom of Choice have failed [Maddy]
13025 Modern views say the Choice set exists, even if it can't be constructed [Maddy]
13026 A large array of theorems depend on the Axiom of Choice [Maddy]
4. Formal Logic / F. Set Theory ST / 5. Conceptions of Set / e. Iterative sets
13019 The Iterative Conception says everything appears at a stage, derived from the preceding appearances [Maddy]
4. Formal Logic / F. Set Theory ST / 5. Conceptions of Set / f. Limitation of Size
13018 Limitation of Size is a vague intuition that over-large sets may generate paradoxes [Maddy]
5. Theory of Logic / A. Overview of Logic / 1. Overview of Logic
8091 Situation theory is logic that takes account of context [Devlin]
5. Theory of Logic / A. Overview of Logic / 2. History of Logic
8087 Golden ages: 1900-1960 for pure logic, and 1950-1985 for applied logic [Devlin]
8089 Montague's intensional logic incorporated the notion of meaning [Devlin]
5. Theory of Logic / B. Logical Consequence / 7. Strict Implication
8082 Where a conditional is purely formal, an implication implies a link between premise and conclusion [Devlin]
5. Theory of Logic / E. Structures of Logic / 1. Logical Form
8072 Sentences of apparent identical form can have different contextual meanings [Devlin]
5. Theory of Logic / G. Quantification / 5. Second-Order Quantification
5740 Second-order logic needs second-order variables and quantification into predicate position [Melia]
5. Theory of Logic / J. Model Theory in Logic / 1. Logical Models
5741 If every model that makes premises true also makes conclusion true, the argument is valid [Melia]
5. Theory of Logic / L. Paradox / 4. Paradoxes in Logic / a. Achilles paradox
8075 Space and time are atomic in the arrow, and divisible in the tortoise [Devlin]
7. Existence / D. Theories of Reality / 8. Facts / a. Facts
5735 Maybe names and predicates can capture any fact [Melia]
5736 No sort of plain language or levels of logic can express modal facts properly [Melia]
9. Objects / F. Identity among Objects / 7. Indiscernible Objects
5746 The Identity of Indiscernibles is contentious for qualities, and trivial for non-qualities [Melia]
10. Modality / A. Necessity / 2. Nature of Necessity
5738 We may be sure that P is necessary, but is it necessarily necessary? [Melia]
10. Modality / A. Necessity / 4. De re / De dicto modality
5732 'De re' modality is about things themselves, 'de dicto' modality is about propositions [Melia]
10. Modality / B. Possibility / 1. Possibility
5739 Sometimes we want to specify in what ways a thing is possible [Melia]
10. Modality / E. Possible worlds / 1. Possible Worlds / a. Possible worlds
5734 Possible worlds make it possible to define necessity and counterfactuals without new primitives [Melia]
5742 In possible worlds semantics the modal operators are treated as quantifiers [Melia]
5743 If possible worlds semantics is not realist about possible worlds, logic becomes merely formal [Melia]
5749 Possible worlds could be real as mathematics, propositions, properties, or like books [Melia]
10. Modality / E. Possible worlds / 2. Nature of Possible Worlds / b. Worlds as fictions
5751 The truth of propositions at possible worlds are implied by the world, just as in books [Melia]
13. Knowledge Criteria / E. Relativism / 5. Language Relativism
8088 People still say the Hopi have no time concepts, despite Whorf's later denial [Devlin]
19. Language / A. Nature of Meaning / 5. Meaning as Verification
5748 We accept unverifiable propositions because of simplicity, utility, explanation and plausibility [Melia]
19. Language / C. Assigning Meanings / 1. Syntax
8073 How do we parse 'time flies like an arrow' and 'fruit flies like an apple'? [Devlin]
19. Language / D. Propositions / 2. Abstract Propositions / a. Propositions as sense
8076 The distinction between sentences and abstract propositions is crucial in logic [Devlin]