Combining Philosophers

All the ideas for Euclid, Duncan Pritchard and Penelope Mackie

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43 ideas

2. Reason / E. Argument / 1. Argument
My modus ponens might be your modus tollens [Pritchard,D]
2. Reason / E. Argument / 6. Conclusive Proof
Proof reveals the interdependence of truths, as well as showing their certainty [Euclid, by Frege]
4. Formal Logic / C. Predicate Calculus PC / 2. Tools of Predicate Calculus / c. Derivations rules of PC
If you pick an arbitrary triangle, things proved of it are true of all triangles [Euclid, by Lemmon]
6. Mathematics / A. Nature of Mathematics / 2. Geometry
Euclid's geometry is synthetic, but Descartes produced an analytic version of it [Euclid, by Resnik]
6. Mathematics / A. Nature of Mathematics / 3. Nature of Numbers / b. Types of number
An assumption that there is a largest prime leads to a contradiction [Euclid, by Brown,JR]
6. Mathematics / A. Nature of Mathematics / 3. Nature of Numbers / m. One
A unit is that according to which each existing thing is said to be one [Euclid]
6. Mathematics / A. Nature of Mathematics / 5. The Infinite / a. The Infinite
Postulate 2 says a line can be extended continuously [Euclid, by Shapiro]
6. Mathematics / B. Foundations for Mathematics / 3. Axioms for Geometry
Euclid relied on obvious properties in diagrams, as well as on his axioms [Potter on Euclid]
Euclid's parallel postulate defines unique non-intersecting parallel lines [Euclid, by Friend]
Euclid needs a principle of continuity, saying some lines must intersect [Shapiro on Euclid]
Euclid says we can 'join' two points, but Hilbert says the straight line 'exists' [Euclid, by Bernays]
Modern geometries only accept various parts of the Euclid propositions [Russell on Euclid]
6. Mathematics / B. Foundations for Mathematics / 5. Definitions of Number / b. Greek arithmetic
Euclid's common notions or axioms are what we must have if we are to learn anything at all [Euclid, by Roochnik]
9. Objects / A. Existence of Objects / 5. Individuation / a. Individuation
A principle of individuation may pinpoint identity and distinctness, now and over time [Mackie,P]
Individuation may include counterfactual possibilities, as well as identity and persistence [Mackie,P]
9. Objects / A. Existence of Objects / 5. Individuation / d. Individuation by haecceity
A haecceity is the essential, simple, unanalysable property of being-this-thing [Mackie,P]
9. Objects / D. Essence of Objects / 1. Essences of Objects
Essentialism must avoid both reduplication of essences, and multiple occupancy by essences [Mackie,P]
9. Objects / D. Essence of Objects / 3. Individual Essences
An individual essence is the properties the object could not exist without [Mackie,P]
No other object can possibly have the same individual essence as some object [Mackie,P]
There are problems both with individual essences and without them [Mackie,P]
9. Objects / D. Essence of Objects / 5. Essence as Kind
Unlike Hesperus=Phosophorus, water=H2O needs further premisses before it is necessary [Mackie,P]
Why are any sortals essential, and why are only some of them essential? [Mackie,P]
9. Objects / D. Essence of Objects / 8. Essence as Explanatory
The Kripke and Putnam view of kinds makes them explanatorily basic, but has modal implications [Mackie,P]
9. Objects / E. Objects over Time / 12. Origin as Essential
Origin is not a necessity, it is just 'tenacious'; we keep it fixed in counterfactual discussions [Mackie,P]
10. Modality / B. Possibility / 9. Counterfactuals
An improbable lottery win can occur in a nearby possible world [Pritchard,D]
10. Modality / E. Possible worlds / 3. Transworld Objects / a. Transworld identity
Transworld identity without individual essences leads to 'bare identities' [Mackie,P]
10. Modality / E. Possible worlds / 3. Transworld Objects / c. Counterparts
De re modality without bare identities or individual essence needs counterparts [Mackie,P]
Things may only be counterparts under some particular relation [Mackie,P]
Possibilities for Caesar must be based on some phase of the real Caesar [Mackie,P]
10. Modality / E. Possible worlds / 3. Transworld Objects / d. Haecceitism
The theory of 'haecceitism' does not need commitment to individual haecceities [Mackie,P]
11. Knowledge Aims / B. Certain Knowledge / 2. Common Sense Certainty
Moore begs the question, or just offers another view, or uses 'know' wrongly [Pritchard,D, by PG]
13. Knowledge Criteria / A. Justification Problems / 2. Justification Challenges / c. Knowledge closure
We can have evidence for seeing a zebra, but no evidence for what is entailed by that [Pritchard,D]
Favouring: an entailment will give better support for the first belief than reason to deny the second [Pritchard,D]
Maybe knowledge just needs relevant discriminations among contrasting cases [Pritchard,D]
13. Knowledge Criteria / A. Justification Problems / 3. Internal or External / a. Pro-internalism
Epistemic internalism usually says justification must be accessible by reflection [Pritchard,D]
13. Knowledge Criteria / A. Justification Problems / 3. Internal or External / b. Pro-externalism
Externalism is better than internalism in dealing with radical scepticism [Pritchard,D]
13. Knowledge Criteria / A. Justification Problems / 3. Internal or External / c. Disjunctivism
Disjunctivism says perceptual justification must be both factual and known by the agent [Pritchard,D]
Metaphysical disjunctivism says normal perceptions and hallucinations are different experiences [Pritchard,D]
13. Knowledge Criteria / C. External Justification / 10. Anti External Justification
Epistemic externalism struggles to capture the idea of epistemic responsibility [Pritchard,D]
13. Knowledge Criteria / D. Scepticism / 1. Scepticism
We assess error against background knowledge, but that is just what radical scepticism challenges [Pritchard,D]
13. Knowledge Criteria / D. Scepticism / 6. Scepticism Critique
Radical scepticism is merely raised, and is not a response to worrying evidence [Pritchard,D]
14. Science / D. Explanation / 2. Types of Explanation / k. Explanations by essence
Locke's kind essences are explanatory, without being necessary to the kind [Mackie,P]
26. Natural Theory / B. Natural Kinds / 6. Necessity of Kinds
Maybe the identity of kinds is necessary, but instances being of that kind is not [Mackie,P]