Combining Philosophers

All the ideas for Agrippa, H.A. Prichard and Rod Girle

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30 ideas

1. Philosophy / D. Nature of Philosophy / 5. Aims of Philosophy / d. Philosophy as puzzles
In philosophy the truth can only be reached via the ruins of the false [Prichard]
2. Reason / A. Nature of Reason / 9. Limits of Reason
Reasoning needs arbitrary faith in preliminary hypotheses (Mode 14) [Agrippa, by Diog. Laertius]
All discussion is full of uncertainty and contradiction (Mode 11) [Agrippa, by Diog. Laertius]
Proofs often presuppose the thing to be proved (Mode 15) [Agrippa, by Diog. Laertius]
All reasoning endlessly leads to further reasoning (Mode 12) [Agrippa, by Diog. Laertius]
4. Formal Logic / B. Propositional Logic PL / 1. Propositional Logic
There are three axiom schemas for propositional logic [Girle]
Propositional logic handles negation, disjunction, conjunction; predicate logic adds quantifiers, predicates, relations [Girle]
4. Formal Logic / B. Propositional Logic PL / 2. Tools of Propositional Logic / a. Symbols of PL
Proposition logic has definitions for its three operators: or, and, and identical [Girle]
4. Formal Logic / B. Propositional Logic PL / 2. Tools of Propositional Logic / e. Axioms of PL
Axiom systems of logic contain axioms, inference rules, and definitions of proof and theorems [Girle]
4. Formal Logic / D. Modal Logic ML / 3. Modal Logic Systems / g. System S4
There are seven modalities in S4, each with its negation [Girle]
4. Formal Logic / D. Modal Logic ML / 3. Modal Logic Systems / h. System S5
◊p → □◊p is the hallmark of S5 [Girle]
S5 has just six modalities, and all strings can be reduced to those [Girle]
4. Formal Logic / D. Modal Logic ML / 4. Alethic Modal Logic
Possible worlds logics use true-in-a-world rather than true [Girle]
Modal logics were studied in terms of axioms, but now possible worlds semantics is added [Girle]
Modal logic has four basic modal negation equivalences [Girle]
5. Theory of Logic / B. Logical Consequence / 7. Strict Implication
Necessary implication is called 'strict implication'; if successful, it is called 'entailment' [Girle]
5. Theory of Logic / H. Proof Systems / 5. Tableau Proof
If an argument is invalid, a truth tree will indicate a counter-example [Girle]
10. Modality / A. Necessity / 3. Types of Necessity
Analytic truths are divided into logically and conceptually necessary [Girle]
10. Modality / B. Possibility / 1. Possibility
Possibilities can be logical, theoretical, physical, economic or human [Girle]
10. Modality / E. Possible worlds / 1. Possible Worlds / a. Possible worlds
A world has 'access' to a world it generates, which is important in possible worlds semantics [Girle]
13. Knowledge Criteria / A. Justification Problems / 2. Justification Challenges / a. Agrippa's trilemma
Agrippa's Trilemma: justification is infinite, or ends arbitrarily, or is circular [Agrippa, by Williams,M]
13. Knowledge Criteria / E. Relativism / 1. Relativism
Everything is perceived in relation to another thing (Mode 13) [Agrippa, by Diog. Laertius]
22. Metaethics / A. Ethics Foundations / 1. Nature of Ethics / c. Purpose of ethics
The 'Ethics' is disappointing, because it fails to try to justify our duties [Prichard]
23. Ethics / C. Virtue Theory / 1. Virtue Theory / c. Particularism
The mistake is to think we can prove what can only be seen directly in moral thinking [Prichard]
I see the need to pay a debt in a particular instance, and any instance will do [Prichard]
The complexities of life make it almost impossible to assess morality from a universal viewpoint [Prichard]
23. Ethics / C. Virtue Theory / 1. Virtue Theory / d. Virtue theory critique
Virtues won't generate an obligation, so it isn't a basis for morality [Prichard]
23. Ethics / D. Deontological Ethics / 2. Duty
We feel obligations to overcome our own failings, and these are not relations to other people [Prichard]
Seeing the goodness of an effect creates the duty to produce it, not the desire [Prichard]
23. Ethics / E. Utilitarianism / 1. Utilitarianism
If pain were instrinsically wrong, it would be immoral to inflict it on ourselves [Prichard]