Combining Texts

All the ideas for 'The Character of Physical Law', 'What is Logic?st2=Ian Hacking' and 'Conditionals (Stanf)'

expand these ideas     |    start again     |     specify just one area for these texts


29 ideas

1. Philosophy / D. Nature of Philosophy / 7. Despair over Philosophy
People generalise because it is easier to understand, and that is mistaken for deep philosophy [Feynman]
2. Reason / D. Definition / 3. Types of Definition
A decent modern definition should always imply a semantics [Hacking]
4. Formal Logic / B. Propositional Logic PL / 2. Tools of Propositional Logic / c. Derivation rules of PL
Conditional Proof is only valid if we accept the truth-functional reading of 'if' [Edgington]
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]
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]
10. Modality / B. Possibility / 6. Probability
A thing works like formal probability if all the options sum to 100% [Edgington]
Conclusion improbability can't exceed summed premise improbability in valid arguments [Edgington]
10. Modality / B. Possibility / 8. Conditionals / b. Types of conditional
Simple indicatives about past, present or future do seem to form a single semantic kind [Edgington]
Maybe forward-looking indicatives are best classed with the subjunctives [Edgington]
10. Modality / B. Possibility / 8. Conditionals / c. Truth-function conditionals
Truth-function problems don't show up in mathematics [Edgington]
Inferring conditionals from disjunctions or negated conjunctions gives support to truth-functionalism [Edgington]
The truth-functional view makes conditionals with unlikely antecedents likely to be true [Edgington]
Doctor:'If patient still alive, change dressing'; Nurse:'Either dead patient, or change dressing'; kills patient! [Edgington]
10. Modality / B. Possibility / 8. Conditionals / d. Non-truthfunction conditionals
Non-truth-functionalist say 'If A,B' is false if A is T and B is F, but deny that is always true for TT,FT and FF [Edgington]
I say "If you touch that wire you'll get a shock"; you don't touch it. How can that make the conditional true? [Edgington]
10. Modality / B. Possibility / 8. Conditionals / e. Supposition conditionals
On the supposition view, believe if A,B to the extent that A&B is nearly as likely as A [Edgington]
10. Modality / B. Possibility / 8. Conditionals / f. Pragmatics of conditionals
Truth-functionalists support some conditionals which we assert, but should not actually believe [Edgington]
Does 'If A,B' say something different in each context, because of the possibiites there? [Edgington]
26. Natural Theory / D. Laws of Nature / 4. Regularities / a. Regularity theory
Physical Laws are rhythms and patterns in nature, revealed by analysis [Feynman]
27. Natural Reality / B. Modern Physics / 2. Electrodynamics / d. Quantum mechanics
Nobody understands quantum mechanics [Feynman]
27. Natural Reality / C. Space / 3. Points in Space
We should regard space as made up of many tiny pieces [Feynman, by Mares]