Combining Philosophers

All the ideas for Hermarchus, Peter Abelard and Joseph Melia

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26 ideas

2. Reason / A. Nature of Reason / 1. On Reason
Consistency is modal, saying propositions are consistent if they could be true together [Melia]
4. Formal Logic / C. Predicate Calculus PC / 1. Predicate Calculus PC
Predicate logic has connectives, quantifiers, variables, predicates, equality, names and brackets [Melia]
4. Formal Logic / D. Modal Logic ML / 1. Modal Logic
First-order predicate calculus is extensional logic, but quantified modal logic is intensional (hence dubious) [Melia]
4. Formal Logic / G. Formal Mereology / 1. Mereology
Abelard's mereology involves privileged and natural divisions, and principal parts [Abelard, by King,P]
5. Theory of Logic / G. Quantification / 5. Second-Order Quantification
Second-order logic needs second-order variables and quantification into predicate position [Melia]
5. Theory of Logic / J. Model Theory in Logic / 1. Logical Models
If every model that makes premises true also makes conclusion true, the argument is valid [Melia]
7. Existence / D. Theories of Reality / 8. Facts / a. Facts
Maybe names and predicates can capture any fact [Melia]
No sort of plain language or levels of logic can express modal facts properly [Melia]
8. Modes of Existence / E. Nominalism / 1. Nominalism / b. Nominalism about universals
If 'animal' is wholly present in Socrates and an ass, then 'animal' is rational and irrational [Abelard, by King,P]
Abelard was an irrealist about virtually everything apart from concrete individuals [Abelard, by King,P]
8. Modes of Existence / E. Nominalism / 3. Predicate Nominalism
Only words can be 'predicated of many'; the universality is just in its mode of signifying [Abelard, by Panaccio]
9. Objects / F. Identity among Objects / 7. Indiscernible Objects
The Identity of Indiscernibles is contentious for qualities, and trivial for non-qualities [Melia]
10. Modality / A. Necessity / 2. Nature of Necessity
We may be sure that P is necessary, but is it necessarily necessary? [Melia]
10. Modality / A. Necessity / 4. De re / De dicto modality
'De re' modality is about things themselves, 'de dicto' modality is about propositions [Melia]
The de dicto-de re modality distinction dates back to Abelard [Abelard, by Orenstein]
10. Modality / B. Possibility / 1. Possibility
Sometimes we want to specify in what ways a thing is possible [Melia]
10. Modality / E. Possible worlds / 1. Possible Worlds / a. Possible worlds
Possible worlds make it possible to define necessity and counterfactuals without new primitives [Melia]
In possible worlds semantics the modal operators are treated as quantifiers [Melia]
If possible worlds semantics is not realist about possible worlds, logic becomes merely formal [Melia]
Possible worlds could be real as mathematics, propositions, properties, or like books [Melia]
10. Modality / E. Possible worlds / 2. Nature of Possible Worlds / b. Worlds as fictions
The truth of propositions at possible worlds are implied by the world, just as in books [Melia]
18. Thought / E. Abstraction / 8. Abstractionism Critique
Abelard's problem is the purely singular aspects of things won't account for abstraction [Panaccio on Abelard]
19. Language / A. Nature of Meaning / 5. Meaning as Verification
We accept unverifiable propositions because of simplicity, utility, explanation and plausibility [Melia]
19. Language / C. Assigning Meanings / 3. Predicates
Nothing external can truly be predicated of an object [Abelard, by Panaccio]
25. Social Practice / F. Life Issues / 6. Animal Rights
Animals are dangerous and nourishing, and can't form contracts of justice [Hermarchus, by Sedley]
26. Natural Theory / B. Natural Kinds / 7. Critique of Kinds
Natural kinds are not special; they are just well-defined resemblance collections [Abelard, by King,P]