Combining Philosophers

All the ideas for Thrasymachus, Penelope Mackie and Alex Orenstein

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33 ideas

4. Formal Logic / B. Propositional Logic PL / 1. Propositional Logic
Sentential logic is consistent (no contradictions) and complete (entirely provable) [Orenstein]
4. Formal Logic / B. Propositional Logic PL / 2. Tools of Propositional Logic / e. Axioms of PL
Axiomatization simply picks from among the true sentences a few to play a special role [Orenstein]
4. Formal Logic / D. Modal Logic ML / 4. Alethic Modal Logic
S4: 'poss that poss that p' implies 'poss that p'; S5: 'poss that nec that p' implies 'nec that p' [Orenstein]
4. Formal Logic / F. Set Theory ST / 1. Set Theory
Unlike elementary logic, set theory is not complete [Orenstein]
4. Formal Logic / G. Formal Mereology / 1. Mereology
Mereology has been exploited by some nominalists to achieve the effects of set theory [Orenstein]
5. Theory of Logic / G. Quantification / 1. Quantification
Traditionally, universal sentences had existential import, but were later treated as conditional claims [Orenstein]
5. Theory of Logic / G. Quantification / 4. Substitutional Quantification
The substitution view of quantification says a sentence is true when there is a substitution instance [Orenstein]
6. Mathematics / A. Nature of Mathematics / 3. Nature of Numbers / b. Types of number
The whole numbers are 'natural'; 'rational' numbers include fractions; the 'reals' include root-2 etc. [Orenstein]
6. Mathematics / C. Sources of Mathematics / 6. Logicism / a. Early logicism
The logicists held that is-a-member-of is a logical constant, making set theory part of logic [Orenstein]
7. Existence / E. Categories / 3. Proposed Categories
Just individuals in Nominalism; add sets for Extensionalism; add properties, concepts etc for Intensionalism [Orenstein]
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 / 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]
14. Science / B. Scientific Theories / 1. Scientific Theory
The Principle of Conservatism says we should violate the minimum number of background beliefs [Orenstein]
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]
19. Language / A. Nature of Meaning / 10. Denial of Meanings
People presume meanings exist because they confuse meaning and reference [Orenstein]
19. Language / C. Assigning Meanings / 3. Predicates
Three ways for 'Socrates is human' to be true are nominalist, platonist, or Montague's way [Orenstein]
19. Language / D. Propositions / 4. Mental Propositions
If two people believe the same proposition, this implies the existence of propositions [Orenstein]
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]
28. God / C. Attitudes to God / 3. Deism
Clearly the gods ignore human affairs, or they would have given us justice [Thrasymachus]