35 ideas
| 18781 | Inconsistency doesn't prevent us reasoning about some system [Mares] |
| 192 | Only one thing can be contrary to something [Plato] |
| 5515 | Imaginary cases are good for revealing our beliefs, rather than the truth [Parfit] |
| 18789 | Intuitionist logic looks best as natural deduction [Mares] |
| 18790 | Intuitionism as natural deduction has no rule for negation [Mares] |
| 18787 | Three-valued logic is useful for a theory of presupposition [Mares] |
| 18793 | Material implication (and classical logic) considers nothing but truth values for implications [Mares] |
| 18784 | In classical logic the connectives can be related elegantly, as in De Morgan's laws [Mares] |
| 18786 | Excluded middle standardly implies bivalence; attacks use non-contradiction, De M 3, or double negation [Mares] |
| 18780 | Standard disjunction and negation force us to accept the principle of bivalence [Mares] |
| 18782 | The connectives are studied either through model theory or through proof theory [Mares] |
| 18783 | Many-valued logics lack a natural deduction system [Mares] |
| 18792 | Situation semantics for logics: not possible worlds, but information in situations [Mares] |
| 18785 | Consistency is semantic, but non-contradiction is syntactic [Mares] |
| 18788 | For intuitionists there are not numbers and sets, but processes of counting and collecting [Mares] |
| 5516 | Reduction can be by identity, or constitution, or elimination [Parfit, by PG] |
| 190 | If asked whether justice itself is just or unjust, you would have to say that it is just [Plato] |
| 20184 | The only real evil is loss of knowledge [Plato] |
| 20185 | The most important things in life are wisdom and knowledge [Plato] |
| 191 | Everything resembles everything else up to a point [Plato] |
| 5514 | Psychologists are interested in identity as a type of person, but philosophers study numerical identity [Parfit] |
| 5521 | If my brain-halves are transplanted into two bodies, I have continuity, and don't need identity [Parfit] |
| 5522 | Over a period of time what matters is not that 'I' persist, but that I have psychological continuity [Parfit] |
| 5519 | It is fine to save two dying twins by merging parts of their bodies into one, and identity is irrelevant [Parfit] |
| 5520 | If two humans are merged surgically, the new identity is a purely verbal problem [Parfit] |
| 5518 | It doesn't matter whether I exist with half my components replaced (any more than an audio system) [Parfit] |
| 18791 | In 'situation semantics' our main concepts are abstracted from situations [Mares] |
| 203 | Courage is knowing what should or shouldn't be feared [Plato] |
| 202 | No one willingly and knowingly embraces evil [Plato] |
| 193 | Some things are good even though they are not beneficial to men [Plato] |
| 197 | Some pleasures are not good, and some pains are not evil [Plato] |
| 200 | People tend only to disapprove of pleasure if it leads to pain, or prevents future pleasure [Plato] |
| 188 | Socrates did not believe that virtue could be taught [Plato] |
| 204 | Socrates is contradicting himself in claiming virtue can't be taught, but that it is knowledge [Plato] |
| 189 | If we punish wrong-doers, it shows that we believe virtue can be taught [Plato] |