Combining Philosophers

Ideas for Chrysippus, Engelbretsen,G/Sayward,C and Jan Lukasiewicz

expand these ideas     |    start again     |     choose another area for these philosophers

display all the ideas for this combination of philosophers

---

6 ideas

5. Theory of Logic / A. Overview of Logic / 4. Pure Logic

13850

In modern logic all formal validity can be characterised syntactically [Engelbretsen/Sayward]

5. Theory of Logic / A. Overview of Logic / 6. Classical Logic

13849

Classical logic rests on truth and models, where constructivist logic rests on defence and refutation [Engelbretsen/Sayward]

5. Theory of Logic / B. Logical Consequence / 5. Modus Ponens

8078	Modus ponens is one of five inference rules identified by the Stoics [Chrysippus, by Devlin]

5. Theory of Logic / D. Assumptions for Logic / 2. Excluded Middle

6023	Every proposition is either true or false [Chrysippus, by Cicero]

5. Theory of Logic / D. Assumptions for Logic / 4. Identity in Logic

13851

Unlike most other signs, = cannot be eliminated [Engelbretsen/Sayward]

5. Theory of Logic / K. Features of Logics / 5. Incompleteness

13852

Axioms are ω-incomplete if the instances are all derivable, but the universal quantification isn't [Engelbretsen/Sayward]