13 ideas
| 23367 | Even pointing a finger should only be done for a reason [Epictetus] |
| 11022 | Gentzen introduced a natural deduction calculus (NK) in 1934 [Gentzen, by Read] |
| 11065 | The inferential role of a logical constant constitutes its meaning [Gentzen, by Hanna] |
| 11023 | The logical connectives are 'defined' by their introduction rules [Gentzen] |
| 11213 | Each logical symbol has an 'introduction' rule to define it, and hence an 'elimination' rule [Gentzen] |
| 10067 | Gentzen proved the consistency of arithmetic from assumptions beyond arithmetic [Gentzen, by Musgrave] |
| 11984 | Asserting a possible property is to say it would have had the property if that world had been actual [Plantinga] |
| 11980 | A possible world is a maximal possible state of affairs [Plantinga] |
| 11982 | If possible Socrates differs from actual Socrates, the Indiscernibility of Identicals says they are different [Plantinga] |
| 11983 | It doesn't matter that we can't identify the possible Socrates; we can't identify adults from baby photos [Plantinga] |
| 11985 | If individuals can only exist in one world, then they can never lack any of their properties [Plantinga] |
| 11986 | The counterparts of Socrates have self-identity, but only the actual Socrates has identity-with-Socrates [Plantinga] |
| 11987 | Counterpart Theory absurdly says I would be someone else if things went differently [Plantinga] |