Combining Philosophers

All the ideas for Hermarchus, Anthony Quinton and Dorothy Edgington

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35 ideas

4. Formal Logic / B. Propositional Logic PL / 2. Tools of Propositional Logic / c. Derivation rules of PL
Conditional Proof is only valid if we accept the truth-functional reading of 'if' [Edgington]
4. Formal Logic / F. Set Theory ST / 7. Natural Sets
A class is natural when everybody can spot further members of it [Quinton]
7. Existence / E. Categories / 5. Category Anti-Realism
Extreme nominalists say all classification is arbitrary convention [Quinton]
8. Modes of Existence / B. Properties / 5. Natural Properties
The naturalness of a class depends as much on the observers as on the objects [Quinton]
Properties imply natural classes which can be picked out by everybody [Quinton]
8. Modes of Existence / D. Universals / 4. Uninstantiated Universals
Uninstantiated properties must be defined using the instantiated ones [Quinton]
9. Objects / A. Existence of Objects / 5. Individuation / b. Individuation by properties
An individual is a union of a group of qualities and a position [Quinton, by Campbell,K]
10. Modality / A. Necessity / 1. Types of Modality
There are two families of modal notions, metaphysical and epistemic, of equal strength [Edgington]
10. Modality / A. Necessity / 5. Metaphysical Necessity
Metaphysical possibility is discovered empirically, and is contrained by nature [Edgington]
10. Modality / A. Necessity / 6. Logical Necessity
Broadly logical necessity (i.e. not necessarily formal logical necessity) is an epistemic notion [Edgington]
An argument is only valid if it is epistemically (a priori) necessary [Edgington]
Logical necessity is epistemic necessity, which is the old notion of a priori [Edgington, by McFetridge]
10. Modality / B. Possibility / 6. Probability
Truth-functional possibilities include the irrelevant, which is a mistake [Edgington]
A thing works like formal probability if all the options sum to 100% [Edgington]
Conclusion improbability can't exceed summed premise improbability in valid arguments [Edgington]
10. Modality / B. Possibility / 8. Conditionals / a. Conditionals
It is a mistake to think that conditionals are statements about how the world is [Edgington]
Validity can preserve certainty in mathematics, but conditionals about contingents are another matter [Edgington]
10. Modality / B. Possibility / 8. Conditionals / b. Types of conditional
There are many different conditional mental states, and different conditional speech acts [Edgington]
Simple indicatives about past, present or future do seem to form a single semantic kind [Edgington]
Maybe forward-looking indicatives are best classed with the subjunctives [Edgington]
10. Modality / B. Possibility / 8. Conditionals / c. Truth-function conditionals
Truth-function problems don't show up in mathematics [Edgington]
Are conditionals truth-functional - do the truth values of A and B determine the truth value of 'If A, B'? [Edgington]
'If A,B' must entail ¬(A & ¬B); otherwise we could have A true, B false, and If A,B true, invalidating modus ponens [Edgington]
Inferring conditionals from disjunctions or negated conjunctions gives support to truth-functionalism [Edgington]
The truth-functional view makes conditionals with unlikely antecedents likely to be true [Edgington]
Doctor:'If patient still alive, change dressing'; Nurse:'Either dead patient, or change dressing'; kills patient! [Edgington]
10. Modality / B. Possibility / 8. Conditionals / d. Non-truthfunction conditionals
A conditional does not have truth conditions [Edgington]
X believes 'if A, B' to the extent that A & B is more likely than A & ¬B [Edgington]
Non-truth-functionalist say 'If A,B' is false if A is T and B is F, but deny that is always true for TT,FT and FF [Edgington]
I say "If you touch that wire you'll get a shock"; you don't touch it. How can that make the conditional true? [Edgington]
10. Modality / B. Possibility / 8. Conditionals / e. Supposition conditionals
Conditionals express what would be the outcome, given some supposition [Edgington]
On the supposition view, believe if A,B to the extent that A&B is nearly as likely as A [Edgington]
10. Modality / B. Possibility / 8. Conditionals / f. Pragmatics of conditionals
Truth-functionalists support some conditionals which we assert, but should not actually believe [Edgington]
Does 'If A,B' say something different in each context, because of the possibiites there? [Edgington]
25. Social Practice / F. Life Issues / 6. Animal Rights
Animals are dangerous and nourishing, and can't form contracts of justice [Hermarchus, by Sedley]