Ideas of Ian Hacking, by Theme
[Canadian, b.1936, At theUniversity of Toronto, and at Stanford University.]
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1. Philosophy / C. History of Philosophy / 4. Later European Philosophy / b. Seventeenth century philosophy
7454

Gassendi is the first great empiricist philosopher

2. Reason / D. Definition / 3. Types of Definition
13838

A decent modern definition should always imply a semantics

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

13834

Gentzen's Cut Rule (or transitivity of deduction) is 'If A  B and B  C, then A  C'

13835

Only Cut reduces complexity, so logic is constructive without it, and it can be dispensed with

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

5. Theory of Logic / A. Overview of Logic / 5. FirstOrder Logic
13840

Firstorder logic is the strongest complete compact theory with LöwenheimSkolem

13844

A limitation of firstorder logic is that it cannot handle branching quantifiers

5. Theory of Logic / A. Overview of Logic / 7. SecondOrder Logic
13842

Secondorder completeness seems to need intensional entities and possible worlds

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

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

5. Theory of Logic / J. Model Theory in Logic / 3. LöwenheimSkolem Theorems
13843

If it is a logic, the LöwenheimSkolem theorem holds for it

10. Modality / B. Possibility / 6. Probability
7447

Probability was fully explained between 1654 and 1812

7448

Probability is statistical (behaviour of chance devices) or epistemological (belief based on evidence)

7449

Epistemological probability based either on logical implications or coherent judgments

13. Knowledge Criteria / B. Internal Justification / 3. Evidentialism / a. Evidence
7450

In the medieval view, only deduction counted as true evidence

7451

Formerly evidence came from people; the new idea was that things provided evidence

14. Science / A. Basis of Science / 3. Experiment
7452

An experiment is a test, or an adventure, or a diagnosis, or a dissection [PG]

14. Science / D. Explanation / 2. Types of Explanation / a. Types of explanation
7459

Follow maths for necessary truths, and jurisprudence for contingent truths
