Combining Philosophers

All the ideas for Pyrrho, David Hilbert and Keith Devlin

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59 ideas

1. Philosophy / B. History of Ideas / 5. Later European Thought
Logic was merely a branch of rhetoric until the scientific 17th century [Devlin]
1. Philosophy / D. Nature of Philosophy / 1. Philosophy
He studied philosophy by suspending his judgement on everything [Pyrrho, by Diog. Laertius]
2. Reason / A. Nature of Reason / 9. Limits of Reason
Sceptics say reason is only an instrument, because reason can only be attacked with reason [Pyrrho, by Diog. Laertius]
3. Truth / G. Axiomatic Truth / 1. Axiomatic Truth
If axioms and their implications have no contradictions, they pass my criterion of truth and existence [Hilbert]
4. Formal Logic / A. Syllogistic Logic / 2. Syllogistic Logic
'No councillors are bankers' and 'All bankers are athletes' implies 'Some athletes are not councillors' [Devlin]
4. Formal Logic / B. Propositional Logic PL / 1. Propositional Logic
Modern propositional inference replaces Aristotle's 19 syllogisms with modus ponens [Devlin]
4. Formal Logic / B. Propositional Logic PL / 2. Tools of Propositional Logic / e. Axioms of PL
Predicate logic retains the axioms of propositional logic [Devlin]
5. Theory of Logic / A. Overview of Logic / 1. Overview of Logic
Situation theory is logic that takes account of context [Devlin]
5. Theory of Logic / A. Overview of Logic / 2. History of Logic
Montague's intensional logic incorporated the notion of meaning [Devlin]
Golden ages: 1900-1960 for pure logic, and 1950-1985 for applied logic [Devlin]
5. Theory of Logic / B. Logical Consequence / 7. Strict Implication
Where a conditional is purely formal, an implication implies a link between premise and conclusion [Devlin]
5. Theory of Logic / D. Assumptions for Logic / 2. Excluded Middle
You would cripple mathematics if you denied Excluded Middle [Hilbert]
5. Theory of Logic / E. Structures of Logic / 1. Logical Form
Sentences of apparent identical form can have different contextual meanings [Devlin]
5. Theory of Logic / K. Features of Logics / 1. Axiomatisation
The facts of geometry, arithmetic or statics order themselves into theories [Hilbert]
Axioms must reveal their dependence (or not), and must be consistent [Hilbert]
5. Theory of Logic / L. Paradox / 4. Paradoxes in Logic / a. Achilles paradox
Space and time are atomic in the arrow, and divisible in the tortoise [Devlin]
6. Mathematics / A. Nature of Mathematics / 1. Mathematics
I aim to establish certainty for mathematical methods [Hilbert]
We believe all mathematical problems are solvable [Hilbert]
Hilbert wanted to prove the consistency of all of mathematics (which realists take for granted) [Hilbert, by Friend]
6. Mathematics / A. Nature of Mathematics / 2. Geometry
Hilbert aimed to eliminate number from geometry [Hilbert, by Hart,WD]
6. Mathematics / A. Nature of Mathematics / 5. The Infinite / a. The Infinite
No one shall drive us out of the paradise the Cantor has created for us [Hilbert]
We extend finite statements with ideal ones, in order to preserve our logic [Hilbert]
Only the finite can bring certainty to the infinite [Hilbert]
6. Mathematics / A. Nature of Mathematics / 5. The Infinite / d. Actual infinite
The idea of an infinite totality is an illusion [Hilbert]
6. Mathematics / A. Nature of Mathematics / 5. The Infinite / j. Infinite divisibility
There is no continuum in reality to realise the infinitely small [Hilbert]
6. Mathematics / B. Foundations for Mathematics / 2. Proof in Mathematics
To decide some questions, we must study the essence of mathematical proof itself [Hilbert]
6. Mathematics / B. Foundations for Mathematics / 3. Axioms for Geometry
Euclid axioms concerns possibilities of construction, but Hilbert's assert the existence of objects [Hilbert, by Chihara]
Hilbert's formalisation revealed implicit congruence axioms in Euclid [Hilbert, by Horsten/Pettigrew]
Hilbert's geometry is interesting because it captures Euclid without using real numbers [Hilbert, by Field,H]
The whole of Euclidean geometry derives from a basic equation and transformations [Hilbert]
6. Mathematics / B. Foundations for Mathematics / 4. Axioms for Number / a. Axioms for numbers
Number theory just needs calculation laws and rules for integers [Hilbert]
6. Mathematics / C. Sources of Mathematics / 4. Mathematical Empiricism / c. Against mathematical empiricism
The existence of an arbitrarily large number refutes the idea that numbers come from experience [Hilbert]
6. Mathematics / C. Sources of Mathematics / 6. Logicism / d. Logicism critique
Logic already contains some arithmetic, so the two must be developed together [Hilbert]
6. Mathematics / C. Sources of Mathematics / 7. Formalism
The grounding of mathematics is 'in the beginning was the sign' [Hilbert]
Hilbert substituted a syntactic for a semantic account of consistency [Hilbert, by George/Velleman]
Hilbert said (to block paradoxes) that mathematical existence is entailed by consistency [Hilbert, by Potter]
The subject matter of mathematics is immediate and clear concrete symbols [Hilbert]
6. Mathematics / C. Sources of Mathematics / 8. Finitism
Hilbert aimed to prove the consistency of mathematics finitely, to show infinities won't produce contradictions [Hilbert, by George/Velleman]
Mathematics divides in two: meaningful finitary statements, and empty idealised statements [Hilbert]
11. Knowledge Aims / B. Certain Knowledge / 1. Certainty
My theory aims at the certitude of mathematical methods [Hilbert]
13. Knowledge Criteria / A. Justification Problems / 1. Justification / a. Justification issues
If we need a criterion of truth, we need to know whether it is the correct criterion [Pyrrho, by Fogelin]
13. Knowledge Criteria / D. Scepticism / 1. Scepticism
The Pyrrhonians attacked the dogmas of professors, not ordinary people [Pyrrho, by Fogelin]
13. Knowledge Criteria / D. Scepticism / 6. Scepticism Critique
Academics said that Pyrrhonians were guilty of 'negative dogmatism' [Pyrrho, by Fogelin]
13. Knowledge Criteria / E. Relativism / 1. Relativism
Perception of things depends on their size or quantity (Mode 8) [Pyrrho, by Diog. Laertius]
Individuals vary in responses and feelings (Mode 2) [Pyrrho, by Diog. Laertius]
Perception varies with viewing distance and angle (Mode 7) [Pyrrho, by Diog. Laertius]
Animals vary in their feelings and judgements (Mode 1) [Pyrrho, by Diog. Laertius]
Judgements vary according to local culture and law (Mode 5) [Pyrrho, by Diog. Laertius]
Perception is affected by expectations (Mode 9) [Pyrrho, by Diog. Laertius]
Objects vary according to which sense perceives them (Mode 3) [Pyrrho, by Diog. Laertius]
Perception of objects depends on surrounding conditions (Mode 6) [Pyrrho, by Diog. Laertius]
Perception varies with madness or disease (Mode 4) [Pyrrho, by Diog. Laertius]
Perception and judgement depend on comparison (Mode 10) [Pyrrho, by Diog. Laertius]
13. Knowledge Criteria / E. Relativism / 5. Language Relativism
People still say the Hopi have no time concepts, despite Whorf's later denial [Devlin]
19. Language / C. Assigning Meanings / 1. Syntax
How do we parse 'time flies like an arrow' and 'fruit flies like an apple'? [Devlin]
19. Language / D. Propositions / 2. Abstract Propositions / a. Propositions as sense
The distinction between sentences and abstract propositions is crucial in logic [Devlin]
26. Natural Theory / C. Causation / 7. Eliminating causation
There are no causes, because they are relative, and alike things can't cause one another [Pyrrho, by Diog. Laertius]
26. Natural Theory / D. Laws of Nature / 8. Scientific Essentialism / d. Knowing essences
By digging deeper into the axioms we approach the essence of sciences, and unity of knowedge [Hilbert]
27. Natural Reality / A. Classical Physics / 1. Mechanics / a. Explaining movement
Motion can't move where it is, and can't move where it isn't, so it can't exist [Pyrrho, by Diog. Laertius]