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All the ideas for 'What is Logic?st1=Ian Hacking', 'Identity and Essence' and 'Disputationes metaphysicae'

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40 ideas

2. Reason / D. Definition / 3. Types of Definition
13838 A decent modern definition should always imply a semantics [Hacking]
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]
8. Modes of Existence / B. Properties / 8. Properties as Modes
16665 There are entities, and then positive 'modes', modifying aspects outside the thing's essence [Suárez]
16666 A mode determines the state and character of a quantity, without adding to it [Suárez]
9. Objects / A. Existence of Objects / 5. Individuation / a. Individuation
12132 Indiscernibility is a necessary and sufficient condition for identity [Brody]
9. Objects / A. Existence of Objects / 5. Individuation / e. Individuation by kind
15834 Brody bases sortal essentialism on properties required throughout something's existence [Brody, by Mackie,P]
9. Objects / B. Unity of Objects / 2. Substance / a. Substance
16667 Substances are incomplete unless they have modes [Suárez, by Pasnau]
9. Objects / C. Structure of Objects / 2. Hylomorphism / a. Hylomorphism
17007 Forms must rule over faculties and accidents, and are the source of action and unity [Suárez]
12140 Modern emphasis is on properties had essentially; traditional emphasis is on sort-defining properties [Brody]
9. Objects / C. Structure of Objects / 2. Hylomorphism / d. Form as unifier
16780 Partial forms of leaf and fruit are united in the whole form of the tree [Suárez]
16758 The best support for substantial forms is the co-ordinated unity of a natural being [Suárez]
9. Objects / C. Structure of Objects / 4. Quantity of an Object
16743 We can get at the essential nature of 'quantity' by knowing bulk and extension [Suárez]
9. Objects / D. Essence of Objects / 5. Essence as Kind
11895 A sortal essence is a property which once possessed always possessed [Brody, by Mackie,P]
12141 Maybe essential properties are those which determine a natural kind? [Brody]
9. Objects / D. Essence of Objects / 6. Essence as Unifier
12137 De re essentialism standardly says all possible objects identical with a have a's essential properties [Brody]
9. Objects / D. Essence of Objects / 7. Essence and Necessity / a. Essence as necessary properties
12142 Essentially, a has P, always had P, must have had P, and has never had a future without P [Brody]
12143 An object having a property essentially is equivalent to its having it necessarily [Brody]
9. Objects / D. Essence of Objects / 8. Essence as Explanatory
12144 Essentialism is justified if the essential properties of things explain their other properties [Brody]
9. Objects / D. Essence of Objects / 12. Essential Parts
12139 Mereological essentialism says that every part that ensures the existence is essential [Brody]
9. Objects / D. Essence of Objects / 14. Knowledge of Essences
16742 We only know essences through non-essential features, esp. those closest to the essence [Suárez]
9. Objects / E. Objects over Time / 12. Origin as Essential
12135 Interrupted objects have two first moments of existence, which could be two beginnings [Brody]
9. Objects / F. Identity among Objects / 1. Concept of Identity
22143 Identity does not exclude possible or imagined difference [Suárez, by Boulter]
22144 Real Essential distinction: A and B are of different natural kinds [Suárez, by Boulter]
22146 Minor Real distinction: B needs A, but A doesn't need B [Suárez, by Boulter]
22145 Major Real distinction: A and B have independent existences [Suárez, by Boulter]
22147 Conceptual/Mental distinction: one thing can be conceived of in two different ways [Suárez, by Boulter]
22148 Modal distinction: A isn't B or its property, but still needs B [Suárez, by Boulter]
9. Objects / F. Identity among Objects / 7. Indiscernible Objects
12130 a and b share all properties; so they share being-identical-with-a; so a = b [Brody]
10. Modality / D. Knowledge of Modality / 4. Conceivable as Possible / a. Conceivable as possible
22149 Scholastics assess possibility by what has actually happened in reality [Suárez, by Boulter]
10. Modality / E. Possible worlds / 3. Transworld Objects / b. Rigid designation
12138 Identity across possible worlds is prior to rigid designation [Brody]
29. Religion / B. Monotheistic Religion / 4. Christianity / c. Angels
16682 Other things could occupy the same location as an angel [Suárez]