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All the ideas for 'Introduction to 'Properties'', 'What Required for Foundation for Maths?' and 'The Logic of What Might Have Been'

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62 ideas

2. Reason / B. Laws of Thought / 6. Ockham's Razor
4037 Ockham's Razor is the principle that we need reasons to believe in entities [Mellor/Oliver]
2. Reason / D. Definition / 2. Aims of Definition
17774 Definitions make our intuitions mathematically useful [Mayberry]
2. Reason / E. Argument / 6. Conclusive Proof
17773 Proof shows that it is true, but also why it must be true [Mayberry]
4. Formal Logic / D. Modal Logic ML / 2. Tools of Modal Logic / b. Terminology of ML
14684 A world is 'accessible' to another iff the first is possible according to the second [Salmon,N]
4. Formal Logic / D. Modal Logic ML / 3. Modal Logic Systems / d. System T
14669 For metaphysics, T may be the only correct system of modal logic [Salmon,N]
4. Formal Logic / D. Modal Logic ML / 3. Modal Logic Systems / f. System B
14667 System B has not been justified as fallacy-free for reasoning on what might have been [Salmon,N]
14668 In B it seems logically possible to have both p true and p is necessarily possibly false [Salmon,N]
14692 System B implies that possibly-being-realized is an essential property of the world [Salmon,N]
4. Formal Logic / D. Modal Logic ML / 3. Modal Logic Systems / g. System S4
14671 What is necessary is not always necessarily necessary, so S4 is fallacious [Salmon,N]
4. Formal Logic / D. Modal Logic ML / 3. Modal Logic Systems / h. System S5
14686 S5 modal logic ignores accessibility altogether [Salmon,N]
14691 S5 believers say that-things-might-have-been-that-way is essential to ways things might have been [Salmon,N]
14693 The unsatisfactory counterpart-theory allows the retention of S5 [Salmon,N]
4. Formal Logic / D. Modal Logic ML / 4. Alethic Modal Logic
14670 Metaphysical (alethic) modal logic concerns simple necessity and possibility (not physical, epistemic..) [Salmon,N]
4. Formal Logic / F. Set Theory ST / 4. Axioms for Sets / a. Axioms for sets
17795 Set theory can't be axiomatic, because it is needed to express the very notion of axiomatisation [Mayberry]
17796 There is a semi-categorical axiomatisation of set-theory [Mayberry]
4. Formal Logic / F. Set Theory ST / 4. Axioms for Sets / f. Axiom of Infinity V
17800 The misnamed Axiom of Infinity says the natural numbers are finite in size [Mayberry]
4. Formal Logic / F. Set Theory ST / 5. Conceptions of Set / e. Iterative sets
17801 The set hierarchy doesn't rely on the dubious notion of 'generating' them [Mayberry]
4. Formal Logic / F. Set Theory ST / 5. Conceptions of Set / f. Limitation of Size
17803 Limitation of size is part of the very conception of a set [Mayberry]
5. Theory of Logic / A. Overview of Logic / 2. History of Logic
17786 The mainstream of modern logic sees it as a branch of mathematics [Mayberry]
5. Theory of Logic / A. Overview of Logic / 5. First-Order Logic
17788 First-order logic only has its main theorems because it is so weak [Mayberry]
5. Theory of Logic / A. Overview of Logic / 7. Second-Order Logic
17791 Only second-order logic can capture mathematical structure up to isomorphism [Mayberry]
5. Theory of Logic / G. Quantification / 2. Domain of Quantification
17787 Big logic has one fixed domain, but standard logic has a domain for each interpretation [Mayberry]
5. Theory of Logic / J. Model Theory in Logic / 3. Löwenheim-Skolem Theorems
17790 No Löwenheim-Skolem logic can axiomatise real analysis [Mayberry]
5. Theory of Logic / K. Features of Logics / 1. Axiomatisation
17779 'Classificatory' axioms aim at revealing similarity in morphology of structures [Mayberry]
17778 Axiomatiation relies on isomorphic structures being essentially the same [Mayberry]
17780 'Eliminatory' axioms get rid of traditional ideal and abstract objects [Mayberry]
5. Theory of Logic / K. Features of Logics / 6. Compactness
17789 No logic which can axiomatise arithmetic can be compact or complete [Mayberry]
6. Mathematics / A. Nature of Mathematics / 3. Nature of Numbers / g. Real numbers
17784 Real numbers can be eliminated, by axiom systems for complete ordered fields [Mayberry]
6. Mathematics / A. Nature of Mathematics / 4. Using Numbers / b. Quantity
17782 Greek quantities were concrete, and ratio and proportion were their science [Mayberry]
17781 Real numbers were invented, as objects, to simplify and generalise 'quantity' [Mayberry]
6. Mathematics / A. Nature of Mathematics / 5. The Infinite / a. The Infinite
17799 Cantor's infinite is an absolute, of all the sets or all the ordinal numbers [Mayberry]
17797 Cantor extended the finite (rather than 'taming the infinite') [Mayberry]
6. Mathematics / B. Foundations for Mathematics / 1. Foundations for Mathematics
17775 If proof and definition are central, then mathematics needs and possesses foundations [Mayberry]
17776 The ultimate principles and concepts of mathematics are presumed, or grasped directly [Mayberry]
17777 Foundations need concepts, definition rules, premises, and proof rules [Mayberry]
17804 Axiom theories can't give foundations for mathematics - that's using axioms to explain axioms [Mayberry]
6. Mathematics / B. Foundations for Mathematics / 4. Axioms for Number / d. Peano arithmetic
17792 1st-order PA is only interesting because of results which use 2nd-order PA [Mayberry]
6. Mathematics / B. Foundations for Mathematics / 4. Axioms for Number / g. Incompleteness of Arithmetic
17793 It is only 2nd-order isomorphism which suggested first-order PA completeness [Mayberry]
6. Mathematics / B. Foundations for Mathematics / 6. Mathematics as Set Theory / a. Mathematics is set theory
17794 Set theory is not just first-order ZF, because that is inadequate for mathematics [Mayberry]
17802 We don't translate mathematics into set theory, because it comes embodied in that way [Mayberry]
17805 Set theory is not just another axiomatised part of mathematics [Mayberry]
8. Modes of Existence / B. Properties / 6. Categorical Properties
4027 Properties are respects in which particular objects may be alike or differ [Mellor/Oliver]
8. Modes of Existence / B. Properties / 12. Denial of Properties
4029 Nominalists ask why we should postulate properties at all [Mellor/Oliver]
9. Objects / A. Existence of Objects / 2. Abstract Objects / a. Nature of abstracta
17785 Real numbers as abstracted objects are now treated as complete ordered fields [Mayberry]
9. Objects / D. Essence of Objects / 15. Against Essentialism
14678 Any property is attached to anything in some possible world, so I am a radical anti-essentialist [Salmon,N]
10. Modality / A. Necessity / 3. Types of Necessity
14680 Logical possibility contains metaphysical possibility, which contains nomological possibility [Salmon,N]
10. Modality / A. Necessity / 5. Metaphysical Necessity
14690 In the S5 account, nested modalities may be unseen, but they are still there [Salmon,N]
14677 Metaphysical necessity is said to be unrestricted necessity, true in every world whatsoever [Salmon,N]
14679 Bizarre identities are logically but not metaphysically possible, so metaphysical modality is restricted [Salmon,N]
14688 Without impossible worlds, the unrestricted modality that is metaphysical has S5 logic [Salmon,N]
14685 Metaphysical necessity is NOT truth in all (unrestricted) worlds; necessity comes first, and is restricted [Salmon,N]
10. Modality / A. Necessity / 6. Logical Necessity
14681 Logical necessity is free of constraints, and may accommodate all of S5 logic [Salmon,N]
10. Modality / A. Necessity / 7. Natural Necessity
14676 Nomological necessity is expressed with intransitive relations in modal semantics [Salmon,N]
10. Modality / C. Sources of Modality / 5. Modality from Actuality
14689 Necessity and possibility are not just necessity and possibility according to the actual world [Salmon,N]
10. Modality / E. Possible worlds / 1. Possible Worlds / b. Impossible worlds
14674 Impossible worlds are also ways for things to be [Salmon,N]
14682 Denial of impossible worlds involves two different confusions [Salmon,N]
14687 Without impossible worlds, how things might have been is the only way for things to be [Salmon,N]
10. Modality / E. Possible worlds / 1. Possible Worlds / e. Against possible worlds
14683 Possible worlds rely on what might have been, so they can' be used to define or analyse modality [Salmon,N]
10. Modality / E. Possible worlds / 2. Nature of Possible Worlds / a. Nature of possible worlds
14672 Possible worlds are maximal abstract ways that things might have been [Salmon,N]
14675 Possible worlds just have to be 'maximal', but they don't have to be consistent [Salmon,N]
10. Modality / E. Possible worlds / 2. Nature of Possible Worlds / c. Worlds as propositions
14673 You can't define worlds as sets of propositions, and then define propositions using worlds [Salmon,N]
18. Thought / E. Abstraction / 5. Abstracta by Negation
4039 Abstractions lack causes, effects and spatio-temporal locations [Mellor/Oliver]