12 ideas
18351 | Propositions are made true, in virtue of something which explains its truth [Lowe] |
14249 | Boolos reinterprets second-order logic as plural logic [Boolos, by Oliver/Smiley] |
10830 | Second-order logic metatheory is set-theoretic, and second-order validity has set-theoretic problems [Boolos] |
10829 | A sentence can't be a truth of logic if it asserts the existence of certain sets [Boolos] |
10832 | '∀x x=x' only means 'everything is identical to itself' if the range of 'everything' is fixed [Boolos] |
10834 | Weak completeness: if it is valid, it is provable. Strong: it is provable from a set of sentences [Boolos] |
13841 | Why should compactness be definitive of logic? [Boolos, by Hacking] |
10833 | Many concepts can only be expressed by second-order logic [Boolos] |
18353 | Modes are beings that are related both to substances and to universals [Lowe] |
18352 | Tropes have existence independently of any entities [Lowe] |
5987 | Alcmaeon was the first to say the brain is central to thinking [Alcmaeon, by Staden, von] |
24043 | Soul must be immortal, since it continually moves, like the heavens [Alcmaeon, by Aristotle] |