18 ideas
| 9540 | A 'value-assignment' (V) is when to each variable in the set V assigns either the value 1 or the value 0 [Hughes/Cresswell] |
| 9541 | The Law of Transposition says (P→Q) → (¬Q→¬P) [Hughes/Cresswell] |
| 9543 | The rules preserve validity from the axioms, so no thesis negates any other thesis [Hughes/Cresswell] |
| 9544 | A system is 'weakly' complete if all wffs are derivable, and 'strongly' if theses are maximised [Hughes/Cresswell] |
| 11976 | Aristotelian essentialism says essences are not relative to specification [Lewis] |
| 11978 | Causal necessities hold in all worlds compatible with the laws of nature [Lewis] |
| 9169 | A statement can be metaphysically necessary and epistemologically contingent [Putnam] |
| 5819 | Conceivability is no proof of possibility [Putnam] |
| 11979 | It doesn't take the whole of a possible Humphrey to win the election [Lewis] |
| 16994 | Counterpart theory is bizarre, as no one cares what happens to a mere counterpart [Kripke on Lewis] |
| 11974 | Counterparts are not the original thing, but resemble it more than other things do [Lewis] |
| 11975 | If the closest resembler to you is in fact quite unlike you, then you have no counterpart [Lewis] |
| 11977 | Essential attributes are those shared with all the counterparts [Lewis] |
| 9168 | I can't distinguish elm trees, but I mean by 'elm' the same set of trees as everybody else [Putnam] |
| 5820 | 'Water' has an unnoticed indexical component, referring to stuff around here [Putnam] |
| 9170 | We need to recognise the contribution of society and of the world in determining reference [Putnam] |
| 5817 | Language is more like a cooperative steamship than an individual hammer [Putnam] |
| 5818 | If water is H2O in the actual world, there is no possible world where it isn't H2O [Putnam] |