12 ideas
22764 | Ordinary speech is not exact about what is true; we say we are digging a well before the well exists [Sext.Empiricus] |
13831 | Logic is based on transitions between sentences [Prawitz] |
23476 | Logical constants seem to be entities in propositions, but are actually pure form [Russell] |
23477 | We use logical notions, so they must be objects - but I don't know what they really are [Russell] |
13825 | Natural deduction introduction rules may represent 'definitions' of logical connectives [Prawitz] |
13823 | In natural deduction, inferences are atomic steps involving just one logical constant [Prawitz] |
18273 | Logical truths are known by their extreme generality [Russell] |
22315 | There can't be a negative of a complex, which is negated by its non-existence [Potter on Russell] |
22762 | Some properties are inseparable from a thing, such as the length, breadth and depth of a body [Sext.Empiricus] |
22759 | Fools, infants and madmen may speak truly, but do not know [Sext.Empiricus] |
22760 | Madmen are reliable reporters of what appears to them [Sext.Empiricus] |
22763 | We can only dream of a winged man if we have experienced men and some winged thing [Sext.Empiricus] |