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All the ideas for 'What is Logic?st1=Ian Hacking', 'The Development of Logic' and 'A Future for Presentism'

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26 ideas

2. Reason / B. Laws of Thought / 2. Sufficient Reason
Is Sufficient Reason self-refuting (no reason to accept it!), or is it a legitimate explanatory tool? [Bourne]
2. Reason / D. Definition / 3. Types of Definition
A decent modern definition should always imply a semantics [Hacking]
3. Truth / H. Deflationary Truth / 1. Redundant Truth
The redundancy theory conflates metalinguistic bivalence with object-language excluded middle [Bourne]
4. Formal Logic / B. Propositional Logic PL / 2. Tools of Propositional Logic / d. Basic theorems of PL
'Thinning' ('dilution') is the key difference between deduction (which allows it) and induction [Hacking]
Gentzen's Cut Rule (or transitivity of deduction) is 'If A |- B and B |- C, then A |- C' [Hacking]
Only Cut reduces complexity, so logic is constructive without it, and it can be dispensed with [Hacking]
4. Formal Logic / F. Set Theory ST / 4. Axioms for Sets / f. Axiom of Infinity V
The axiom of infinity is not a truth of logic, and its adoption is an abandonment of logicism [Kneale,W and M]
5. Theory of Logic / A. Overview of Logic / 4. Pure Logic
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
First-order logic is the strongest complete compact theory with Löwenheim-Skolem [Hacking]
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
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
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
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
If it is a logic, the Löwenheim-Skolem theorem holds for it [Hacking]
8. Modes of Existence / A. Relations / 1. Nature of Relations
All relations between spatio-temporal objects are either spatio-temporal, or causal [Bourne]
It is a necessary condition for the existence of relations that both of the relata exist [Bourne]
27. Natural Reality / B. Modern Physics / 1. Relativity / a. Special relativity
The idea of simultaneity in Special Relativity is full of verificationist assumptions [Bourne]
Relativity denies simultaneity, so it needs past, present and future (unlike Presentism) [Bourne]
27. Natural Reality / D. Time / 1. Nature of Time / a. Absolute time
Special Relativity allows an absolute past, future, elsewhere and simultaneity [Bourne]
27. Natural Reality / D. Time / 1. Nature of Time / g. Growing block
No-Futurists believe in past and present, but not future, and say the world grows as facts increase [Bourne]
27. Natural Reality / D. Time / 1. Nature of Time / h. Presentism
How can presentists talk of 'earlier than', and distinguish past from future? [Bourne]
Presentism seems to deny causation, because the cause and the effect can never coexist [Bourne]
Since presentists treat the presentness of events as basic, simultaneity should be define by that means [Bourne]
27. Natural Reality / D. Time / 2. Passage of Time / d. Time series
Time is tensed or tenseless; the latter says all times and objects are real, and there is no passage of time [Bourne]
B-series objects relate to each other; A-series objects relate to the present [Bourne]
27. Natural Reality / D. Time / 2. Passage of Time / e. Tensed (A) series
Time flows, past is fixed, future is open, future is feared but not past, we remember past, we plan future [Bourne]