Combining Philosophers

All the ideas for Dag Prawitz, Paul Boghossian and Ian Hacking

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38 ideas

1. Philosophy / C. History of Philosophy / 4. Later European Philosophy / b. Seventeenth century philosophy
Gassendi is the first great empiricist philosopher [Hacking]
2. Reason / D. Definition / 3. Types of Definition
A decent modern definition should always imply a semantics [Hacking]
2. Reason / D. Definition / 4. Real Definition
A sentence may simultaneously define a term, and also assert a fact [Boghossian]
3. Truth / H. Deflationary Truth / 3. Minimalist Truth
Minimalism is incoherent, as it implies that truth both is and is not a property [Boghossian, by Horwich]
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 / 1. Overview of Logic
Logic is based on transitions between sentences [Prawitz]
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 / B. Logical Consequence / 1. Logical Consequence
Logical consequence isn't a black box (Tarski's approach); we should explain how arguments work [Prawitz]
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]
Natural deduction introduction rules may represent 'definitions' of logical connectives [Prawitz]
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 / H. Proof Systems / 4. Natural Deduction
In natural deduction, inferences are atomic steps involving just one logical constant [Prawitz]
5. Theory of Logic / I. Semantics of Logic / 2. Formal Truth
Conventionalism agrees with realists that logic has truth values, but not over the source [Boghossian]
5. Theory of Logic / J. Model Theory in Logic / 1. Logical Models
Model theory looks at valid sentences and consequence, but not how we know these things [Prawitz]
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
Probability was fully explained between 1654 and 1812 [Hacking]
Probability is statistical (behaviour of chance devices) or epistemological (belief based on evidence) [Hacking]
Epistemological probability based either on logical implications or coherent judgments [Hacking]
12. Knowledge Sources / A. A Priori Knowledge / 4. A Priori as Necessities
'Snow is white or it isn't' is just true, not made true by stipulation [Boghossian]
12. Knowledge Sources / A. A Priori Knowledge / 8. A Priori as Analytic
The a priori is explained as analytic to avoid a dubious faculty of intuition [Boghossian]
That logic is a priori because it is analytic resulted from explaining the meaning of logical constants [Boghossian]
We can't hold a sentence true without evidence if we can't agree which sentence is definitive of it [Boghossian]
12. Knowledge Sources / A. A Priori Knowledge / 11. Denying the A Priori
We may have strong a priori beliefs which we pragmatically drop from our best theory [Boghossian]
12. Knowledge Sources / E. Direct Knowledge / 2. Intuition
If we learn geometry by intuition, how could this faculty have misled us for so long? [Boghossian]
13. Knowledge Criteria / B. Internal Justification / 3. Evidentialism / a. Evidence
In the medieval view, only deduction counted as true evidence [Hacking]
Formerly evidence came from people; the new idea was that things provided evidence [Hacking]
14. Science / A. Basis of Science / 3. Experiment
An experiment is a test, or an adventure, or a diagnosis, or a dissection [Hacking, by PG]
14. Science / D. Explanation / 2. Types of Explanation / a. Types of explanation
Follow maths for necessary truths, and jurisprudence for contingent truths [Hacking]
19. Language / A. Nature of Meaning / 7. Meaning Holism / c. Meaning by Role
If meaning depends on conceptual role, what properties are needed to do the job? [Boghossian]
'Conceptual role semantics' says terms have meaning from sentences and/or inferences [Boghossian]
19. Language / A. Nature of Meaning / 8. Synonymy
Could expressions have meaning, without two expressions possibly meaning the same? [Boghossian]
19. Language / E. Analyticity / 2. Analytic Truths
There are no truths in virtue of meaning, but there is knowability in virtue of understanding [Boghossian, by Jenkins]
19. Language / E. Analyticity / 3. Analytic and Synthetic
Epistemological analyticity: grasp of meaning is justification; metaphysical: truth depends on meaning [Boghossian]