Combining Texts

All the ideas for 'What is Logic?st1=Ian Hacking', 'Armstrong on combinatorial possibility' and 'Primitive Thisness and Primitive Identity'

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28 ideas

1. Philosophy / F. Analytic Philosophy / 1. Nature of Analysis
15545 Armstrong's analysis seeks truthmakers rather than definitions [Lewis]
2. Reason / D. Definition / 3. Types of Definition
13838 A decent modern definition should always imply a semantics [Hacking]
3. Truth / B. Truthmakers / 5. What Makes Truths / a. What makes truths
15546 Predications aren't true because of what exists, but of how it exists [Lewis]
3. Truth / B. Truthmakers / 5. What Makes Truths / d. Being makes truths
15548 Say 'truth is supervenient on being', but construe 'being' broadly [Lewis]
3. Truth / B. Truthmakers / 9. Making Past Truths
14399 Presentism says only the present exists, so there is nothing for tensed truths to supervene on [Lewis]
4. Formal Logic / B. Propositional Logic PL / 2. Tools of Propositional Logic / d. Basic theorems of PL
13833 'Thinning' ('dilution') is the key difference between deduction (which allows it) and induction [Hacking]
13834 Gentzen's Cut Rule (or transitivity of deduction) is 'If A |- B and B |- C, then A |- C' [Hacking]
13835 Only Cut reduces complexity, so logic is constructive without it, and it can be dispensed with [Hacking]
5. Theory of Logic / A. Overview of Logic / 4. Pure Logic
13845 The various logics are abstractions made from terms like 'if...then' in English [Hacking]
5. Theory of Logic / A. Overview of Logic / 5. First-Order Logic
13840 First-order logic is the strongest complete compact theory with Löwenheim-Skolem [Hacking]
13844 A limitation of first-order logic is that it cannot handle branching quantifiers [Hacking]
5. Theory of Logic / A. Overview of Logic / 7. Second-Order Logic
13842 Second-order completeness seems to need intensional entities and possible worlds [Hacking]
5. Theory of Logic / E. Structures of Logic / 2. Logical Connectives / a. Logical connectives
13837 With a pure notion of truth and consequence, the meanings of connectives are fixed syntactically [Hacking]
5. Theory of Logic / E. Structures of Logic / 4. Variables in Logic
13839 Perhaps variables could be dispensed with, by arrows joining places in the scope of quantifiers [Hacking]
5. Theory of Logic / J. Model Theory in Logic / 3. Löwenheim-Skolem Theorems
13843 If it is a logic, the Löwenheim-Skolem theorem holds for it [Hacking]
7. Existence / D. Theories of Reality / 9. States of Affairs
15543 How do things combine to make states of affairs? Constituents can repeat, and fail to combine [Lewis]
9. Objects / A. Existence of Objects / 5. Individuation / d. Individuation by haecceity
14508 A 'thisness' is a thing's property of being identical with itself (not the possession of self-identity) [Adams,RM]
14511 There are cases where mere qualities would not ensure an intrinsic identity [Adams,RM]
9. Objects / D. Essence of Objects / 9. Essence and Properties
12031 Essences are taken to be qualitative properties [Adams,RM]
9. Objects / F. Identity among Objects / 7. Indiscernible Objects
12034 If the universe was cyclical, totally indiscernible events might occur from time to time [Adams,RM]
14510 Two events might be indiscernible yet distinct, if there was a universe cyclical in time [Adams,RM]
16455 Black's two globes might be one globe in highly curved space [Adams,RM]
10. Modality / E. Possible worlds / 2. Nature of Possible Worlds / a. Nature of possible worlds
14507 Are possible worlds just qualities, or do they include primitive identities as well? [Adams,RM]
10. Modality / E. Possible worlds / 2. Nature of Possible Worlds / b. Worlds as fictions
11964 Possible worlds are world-stories, maximal descriptions of whole non-existent worlds [Adams,RM, by Molnar]
10. Modality / E. Possible worlds / 3. Transworld Objects / d. Haecceitism
16451 Adams says anti-haecceitism reduces all thisness to suchness [Adams,RM, by Stalnaker]
11901 Haecceitism may or may not involve some logical connection to essence [Adams,RM, by Mackie,P]
14512 Moderate Haecceitism says transworld identities are primitive, but connected to qualities [Adams,RM]
19. Language / B. Reference / 3. Direct Reference / a. Direct reference
12032 Direct reference is by proper names, or indexicals, or referential uses of descriptions [Adams,RM]