27 ideas
13838 | A decent modern definition should always imply a semantics [Hacking] |
15134 | The truthmaker principle requires some specific named thing to make the difference [Williamson] |
15141 | Truthmaker is incompatible with modal semantics of varying domains [Williamson] |
15140 | The converse Barcan formula will not allow contingent truths to have truthmakers [Williamson] |
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] |
15131 | If metaphysical possibility is not a contingent matter, then S5 seems to suit it best [Williamson] |
15135 | If the domain of propositional quantification is constant, the Barcan formulas hold [Williamson] |
15139 | Converse Barcan: could something fail to meet a condition, if everything meets that condition? [Williamson] |
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] |
18492 | Not all quantification is either objectual or substitutional [Williamson] |
15136 | Substitutional quantification is metaphysical neutral, and equivalent to a disjunction of instances [Williamson] |
15138 | Not all quantification is objectual or substitutional [Williamson] |
13843 | If it is a logic, the Löwenheim-Skolem theorem holds for it [Hacking] |
13163 | Circles must be bounded, so cannot be infinite [Leibniz] |
15137 | If 'fact' is a noun, can we name the fact that dogs bark 'Mary'? [Williamson] |
15142 | Our ability to count objects across possibilities favours the Barcan formulas [Williamson] |
13162 | Sloth's Syllogism: either it can't happen, or it is inevitable without my effort [Leibniz] |
15133 | A thing can't be the only necessary existent, because its singleton set would be as well [Williamson] |
19339 | Evil is a negation of good, which arises from non-being [Leibniz] |
13164 | God only made sin possible because a much greater good can be derived from it [Leibniz] |