Combining Texts

All the ideas for 'Actualism and Possible Worlds', 'An Introduction to Modal Logic' and 'Leibniz'

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13 ideas

4. Formal Logic / B. Propositional Logic PL / 2. Tools of Propositional Logic / b. Terminology of PL
A 'value-assignment' (V) is when to each variable in the set V assigns either the value 1 or the value 0 [Hughes/Cresswell]
4. Formal Logic / B. Propositional Logic PL / 2. Tools of Propositional Logic / d. Basic theorems of PL
The Law of Transposition says (P→Q) → (¬Q→¬P) [Hughes/Cresswell]
4. Formal Logic / B. Propositional Logic PL / 4. Soundness of PL
The rules preserve validity from the axioms, so no thesis negates any other thesis [Hughes/Cresswell]
5. Theory of Logic / K. Features of Logics / 4. Completeness
A system is 'weakly' complete if all wffs are derivable, and 'strongly' if theses are maximised [Hughes/Cresswell]
7. Existence / A. Nature of Existence / 3. Being / a. Nature of Being
Necessary beings (numbers, properties, sets, propositions, states of affairs, God) exist in all possible worlds [Plantinga]
9. Objects / D. Essence of Objects / 1. Essences of Objects
Socrates is a contingent being, but his essence is not; without Socrates, his essence is unexemplified [Plantinga]
10. Modality / B. Possibility / 1. Possibility
Early modern possibility is what occurs sometime; for Leibniz, it is what is not contradictory [Arthur,R]
10. Modality / E. Possible worlds / 1. Possible Worlds / a. Possible worlds
Possible worlds clarify possibility, propositions, properties, sets, counterfacts, time, determinism etc. [Plantinga]
10. Modality / E. Possible worlds / 1. Possible Worlds / d. Possible worlds actualism
Plantinga's actualism is nominal, because he fills actuality with possibilia [Stalnaker on Plantinga]
17. Mind and Body / A. Mind-Body Dualism / 4. Occasionalism
Occasionalism contradicts the Eucharist, which needs genuine changes of substance [Arthur,R]
19. Language / C. Assigning Meanings / 8. Possible Worlds Semantics
Plantinga has domains of sets of essences, variables denoting essences, and predicates as functions [Plantinga, by Stalnaker]
Plantinga's essences have their own properties - so will have essences, giving a hierarchy [Stalnaker on Plantinga]
19. Language / D. Propositions / 1. Propositions
Are propositions and states of affairs two separate things, or only one? I incline to say one [Plantinga]