35 ideas
| 7786 | Propositional logic handles negation, disjunction, conjunction; predicate logic adds quantifiers, predicates, relations [Girle] |
| 7798 | There are three axiom schemas for propositional logic [Girle] |
| 7799 | Proposition logic has definitions for its three operators: or, and, and identical [Girle] |
| 7797 | Axiom systems of logic contain axioms, inference rules, and definitions of proof and theorems [Girle] |
| 7794 | There are seven modalities in S4, each with its negation [Girle] |
| 7793 | ◊p → □◊p is the hallmark of S5 [Girle] |
| 7795 | S5 has just six modalities, and all strings can be reduced to those [Girle] |
| 7787 | Possible worlds logics use true-in-a-world rather than true [Girle] |
| 7788 | Modal logic has four basic modal negation equivalences [Girle] |
| 7796 | Modal logics were studied in terms of axioms, but now possible worlds semantics is added [Girle] |
| 7789 | Necessary implication is called 'strict implication'; if successful, it is called 'entailment' [Girle] |
| 7790 | If an argument is invalid, a truth tree will indicate a counter-example [Girle] |
| 17000 | We might fix identities for small particulars, but it is utopian to hope for such things [Kripke] |
| 11868 | A different piece of wood could have been used for that table; constitution isn't identity [Wiggins on Kripke] |
| 17044 | A relation can clearly be reflexive, and identity is the smallest reflexive relation [Kripke] |
| 16999 | A vague identity may seem intransitive, and we might want to talk of 'counterparts' [Kripke] |
| 7800 | Analytic truths are divided into logically and conceptually necessary [Girle] |
| 17058 | What many people consider merely physically necessary I consider completely necessary [Kripke] |
| 4970 | What is often held to be mere physical necessity is actually metaphysical necessity [Kripke] |
| 17059 | Unicorns are vague, so no actual or possible creature could count as a unicorn [Kripke] |
| 7801 | Possibilities can be logical, theoretical, physical, economic or human [Girle] |
| 7792 | A world has 'access' to a world it generates, which is important in possible worlds semantics [Girle] |
| 4950 | Possible worlds are useful in set theory, but can be very misleading elsewhere [Kripke] |
| 17003 | Kaplan's 'Dthat' is a useful operator for transforming a description into a rigid designation [Kripke] |
| 9221 | The best known objection to counterparts is Kripke's, that Humphrey doesn't care if his counterpart wins [Kripke, by Sider] |
| 22868 | The value and truth of knowledge are measured by success in activity [Dewey] |
| 17052 | The a priori analytic truths involving fixing of reference are contingent [Kripke] |
| 4969 | I regard the mind-body problem as wide open, and extremely confusing [Kripke] |
| 22865 | Habits constitute the self [Dewey] |
| 4956 | A description may fix a reference even when it is not true of its object [Kripke] |
| 17032 | Even if Gödel didn't produce his theorems, he's still called 'Gödel' [Kripke] |
| 22871 | The good people are those who improve; the bad are those who deteriorate [Dewey] |
| 22876 | Democracy is the development of human nature when it shares in the running of communal activities [Dewey] |
| 22875 | Democracy is not just a form of government; it is a mode of shared living [Dewey] |
| 22874 | Individuality is only developed within groups [Dewey] |