35 ideas
15169 | Metaphysics is clarifying how we speak and think (and possibly improving it) [Sidelle] |
13838 | A decent modern definition should always imply a semantics [Hacking] |
15164 | We seem to base necessities on thought experiments and imagination [Sidelle] |
13833 | 'Thinning' ('dilution') is the key difference between deduction (which allows it) and induction [Hacking] |
13834 | Gentzen's Cut Rule (or transitivity of deduction) is 'If A |- B and B |- C, then A |- C' [Hacking] |
13835 | Only Cut reduces complexity, so logic is constructive without it, and it can be dispensed with [Hacking] |
13845 | The various logics are abstractions made from terms like 'if...then' in English [Hacking] |
13840 | First-order logic is the strongest complete compact theory with Löwenheim-Skolem [Hacking] |
13844 | A limitation of first-order logic is that it cannot handle branching quantifiers [Hacking] |
13842 | Second-order completeness seems to need intensional entities and possible worlds [Hacking] |
13837 | With a pure notion of truth and consequence, the meanings of connectives are fixed syntactically [Hacking] |
13839 | Perhaps variables could be dispensed with, by arrows joining places in the scope of quantifiers [Hacking] |
13843 | If it is a logic, the Löwenheim-Skolem theorem holds for it [Hacking] |
15180 | There doesn't seem to be anything in the actual world that can determine modal facts [Sidelle] |
15184 | Causal reference presupposes essentialism if it refers to modally extended entities [Sidelle] |
15172 | Clearly, essential predications express necessary properties [Sidelle] |
15181 | Being a deepest explanatory feature is an actual, not a modal property [Sidelle] |
15173 | That the essence of water is its microstructure is a convention, not a discovery [Sidelle] |
15185 | We aren't clear about 'same stuff as this', so a principle of individuation is needed to identify it [Sidelle] |
15175 | Evaluation of de dicto modalities does not depend on the identity of its objects [Sidelle] |
15032 | Necessary a posteriori is conventional for necessity and nonmodal for a posteriority [Sidelle, by Sider] |
15179 | To know empirical necessities, we need empirical facts, plus conventions about which are necessary [Sidelle] |
15171 | The necessary a posteriori is statements either of identity or of essence [Sidelle] |
15167 | Empiricism explores necessities and concept-limits by imagining negations of truths [Sidelle] |
15177 | Contradictoriness limits what is possible and what is imaginable [Sidelle] |
15176 | The individuals and kinds involved in modality are also a matter of convention [Sidelle] |
15174 | A thing doesn't need transworld identity prior to rigid reference - that could be a convention of the reference [Sidelle] |
15183 | 'Dthat' operates to make a singular term into a rigid term [Sidelle] |
15165 | A priori knowledge is entirely of analytic truths [Sidelle] |
15168 | That water is essentially H2O in some way concerns how we use 'water' [Sidelle] |
15166 | Causal reference seems to get directly at the object, thus leaving its nature open [Sidelle] |
15182 | Because some entities overlap, reference must have analytic individuation principles [Sidelle] |
1748 | Archelaus was the first person to say that the universe is boundless [Archelaus, by Diog. Laertius] |
15178 | Can anything in science reveal the necessity of what it discovers? [Sidelle] |
5989 | Archelaus said life began in a primeval slime [Archelaus, by Schofield] |