16 ideas
| 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] |
| 12756 | Substance is a force for acting and being acted upon [Leibniz] |
| 12755 | Final causes can help with explanations in physics [Leibniz] |
| 12760 | Something rather like souls (though not intelligent) could be found everywhere [Leibniz] |
| 468 | Musical performance can reveal a range of virtues [Damon of Ath.] |
| 12759 | There are atoms of substance, but no atoms of bulk or extension [Leibniz] |
| 12718 | Secondary matter is active and complete; primary matter is passive and incomplete [Leibniz] |
| 11854 | If there is some trace of God in things, that would explain their natural force [Leibniz] |
| 12758 | It is plausible to think substances contain the same immanent force seen in our free will [Leibniz] |
| 19408 | To say that nature or the one universal substance is God is a pernicious doctrine [Leibniz] |