35 ideas
13838 | A decent modern definition should always imply a semantics [Hacking] |
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] |
7785 | The use of plurals doesn't commit us to sets; there do not exist individuals and collections [Boolos] |
10699 | Does a bowl of Cheerios contain all its sets and subsets? [Boolos] |
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] |
10225 | Monadic second-order logic might be understood in terms of plural quantifiers [Boolos, by Shapiro] |
10736 | Boolos showed how plural quantifiers can interpret monadic second-order logic [Boolos, by Linnebo] |
10780 | Any sentence of monadic second-order logic can be translated into plural first-order logic [Boolos, by Linnebo] |
10697 | Identity is clearly a logical concept, and greatly enhances predicate calculus [Boolos] |
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] |
13671 | Second-order quantifiers are just like plural quantifiers in ordinary language, with no extra ontology [Boolos, by Shapiro] |
10267 | We should understand second-order existential quantifiers as plural quantifiers [Boolos, by Shapiro] |
10698 | Plural forms have no more ontological commitment than to first-order objects [Boolos] |
7806 | Boolos invented plural quantification [Boolos, by Benardete,JA] |
13843 | If it is a logic, the Löwenheim-Skolem theorem holds for it [Hacking] |
10700 | First- and second-order quantifiers are two ways of referring to the same things [Boolos] |
3926 | The human heart has a natural concern for public good [Hume] |
3929 | No moral theory is of any use if it doesn't serve the interests of the individual concerned [Hume] |
3925 | Personal Merit is the possession of useful or agreeable mental qualities [Hume] |
3922 | Justice only exists to support society [Hume] |
23560 | If we all naturally had everything we could ever desire, the virtue of justice would be irrelevant [Hume] |
3918 | Moral philosophy aims to show us our duty [Hume] |
3919 | Conclusions of reason do not affect our emotions or decisions to act [Hume] |
3928 | Virtue just requires careful calculation and a preference for the greater happiness [Hume] |
3923 | No one would cause pain to a complete stranger who happened to be passing [Hume] |
3924 | Nature makes private affections come first, because public concerns are spread too thinly [Hume] |
3921 | The safety of the people is the supreme law [Hume] |
3927 | Society prefers helpful lies to harmful truth [Hume] |
3920 | If you equalise possessions, people's talents will make them unequal again [Hume] |