Combining Philosophers

All the ideas for Roderick Firth, Feferman / Feferman and Francis de Vitoria

expand these ideas     |    start again     |     specify just one area for these philosophers


17 ideas

4. Formal Logic / F. Set Theory ST / 4. Axioms for Sets / j. Axiom of Choice IX
The Axiom of Choice is consistent with the other axioms of set theory [Feferman/Feferman]
Axiom of Choice: a set exists which chooses just one element each of any set of sets [Feferman/Feferman]
Platonist will accept the Axiom of Choice, but others want criteria of selection or definition [Feferman/Feferman]
The Trichotomy Principle is equivalent to the Axiom of Choice [Feferman/Feferman]
Cantor's theories needed the Axiom of Choice, but it has led to great controversy [Feferman/Feferman]
5. Theory of Logic / J. Model Theory in Logic / 1. Logical Models
A structure is a 'model' when the axioms are true. So which of the structures are models? [Feferman/Feferman]
Tarski and Vaught established the equivalence relations between first-order structures [Feferman/Feferman]
5. Theory of Logic / J. Model Theory in Logic / 3. Löwenheim-Skolem Theorems
Löwenheim-Skolem says if the sentences are countable, so is the model [Feferman/Feferman]
Löwenheim-Skolem Theorem, and Gödel's completeness of first-order logic, the earliest model theory [Feferman/Feferman]
5. Theory of Logic / K. Features of Logics / 4. Completeness
If a sentence holds in every model of a theory, then it is logically derivable from the theory [Feferman/Feferman]
5. Theory of Logic / K. Features of Logics / 7. Decidability
'Recursion theory' concerns what can be solved by computing machines [Feferman/Feferman]
Both Principia Mathematica and Peano Arithmetic are undecidable [Feferman/Feferman]
12. Knowledge Sources / B. Perception / 4. Sense Data / d. Sense-data problems
We are not conscious of pure liquidity, but of the liquidity of water [Firth]
25. Social Practice / E. Policies / 1. War / a. Just wars
The only just cause for a war is a wrong received [Vitoria]
Leaders can only attack foreigners who have done wrong (as with their own subjects) [Vitoria]
25. Social Practice / E. Policies / 1. War / c. Combatants
Princes should not justify a war to their subjects, and doing so would undermine the state [Vitoria]
25. Social Practice / E. Policies / 1. War / d. Non-combatants
Sacking a city is lawful if it motivates the attacking troops [Vitoria]