42 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] |
| 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] |
| 12132 | Indiscernibility is a necessary and sufficient condition for identity [Brody] |
| 15834 | Brody bases sortal essentialism on properties required throughout something's existence [Brody, by Mackie,P] |
| 12140 | Modern emphasis is on properties had essentially; traditional emphasis is on sort-defining properties [Brody] |
| 11895 | A sortal essence is a property which once possessed always possessed [Brody, by Mackie,P] |
| 12141 | Maybe essential properties are those which determine a natural kind? [Brody] |
| 12137 | De re essentialism standardly says all possible objects identical with a have a's essential properties [Brody] |
| 12142 | Essentially, a has P, always had P, must have had P, and has never had a future without P [Brody] |
| 12143 | An object having a property essentially is equivalent to its having it necessarily [Brody] |
| 12144 | Essentialism is justified if the essential properties of things explain their other properties [Brody] |
| 12139 | Mereological essentialism says that every part that ensures the existence is essential [Brody] |
| 12135 | Interrupted objects have two first moments of existence, which could be two beginnings [Brody] |
| 12130 | a and b share all properties; so they share being-identical-with-a; so a = b [Brody] |
| 12138 | Identity across possible worlds is prior to rigid designation [Brody] |
| 23154 | We divide mankind into friend and foe, and cooperate with one and compete with the other [Russell] |
| 23153 | Gradually loyalty to a creed increased, which could even outweigh nationality [Russell] |
| 23152 | Increasingly war expands communities, and unifies them through fear [Russell] |
| 23155 | In early societies the leaders needed cohesion, but the rest just had to obey [Russell] |
| 23156 | The economic and political advantages of great size seem to have no upper limit [Russell] |
| 23157 | Government has a negative purpose, to prevent trouble, and a positive aim of realising our desires [Russell] |
| 23151 | A monarch is known to everyone in the group, and can thus unite large groups [Russell] |
| 23167 | Power should be with smaller bodies, as long as it doesn't restrict central powers [Russell] |
| 23163 | In an anarchy universities, research, books, and even seaside holidays, would be impossible [Russell] |
| 23168 | A state is essential, to control greedy or predatory impulses [Russell] |
| 23166 | In democracy we are more aware of being governed than of our tiny share in government [Russell] |
| 23162 | Managers are just as remote from workers under nationalisation as under capitalism [Russell] |
| 23165 | Socialists say economic justice needs some state control of industries, and of foreign trade [Russell] |
| 23160 | Being a slave of society is hardly better than being a slave of a despot [Russell] |
| 23158 | Slavery began the divorce between the work and the purposes of the worker [Russell] |
| 23161 | Slaves can be just as equal as free people [Russell] |
| 23159 | Scarce goods may be denied entirely, to avoid their unequal distribution [Russell] |
| 23164 | Modern justice is seen as equality, apart from modest extra rewards for exceptional desert [Russell] |