21 ideas
3067 | A philosopher should have principles ready for understanding, like a surgeon with instruments [Aurelius] |
10301 | The axiom of choice is controversial, but it could be replaced [Shapiro] |
10588 | First-order logic is Complete, and Compact, with the Löwenheim-Skolem Theorems [Shapiro] |
10298 | Some say that second-order logic is mathematics, not logic [Shapiro] |
10299 | If the aim of logic is to codify inferences, second-order logic is useless [Shapiro] |
10300 | Logical consequence can be defined in terms of the logical terminology [Shapiro] |
10290 | Second-order variables also range over properties, sets, relations or functions [Shapiro] |
10297 | The Löwenheim-Skolem theorem seems to be a defect of first-order logic [Shapiro] |
10590 | Up Löwenheim-Skolem: if natural numbers satisfy wffs, then an infinite domain satisfies them [Shapiro] |
10292 | Downward Löwenheim-Skolem: if there's an infinite model, there is a countable model [Shapiro] |
10296 | The Löwenheim-Skolem Theorems fail for second-order languages with standard semantics [Shapiro] |
10294 | Second-order logic has the expressive power for mathematics, but an unworkable model theory [Shapiro] |
3072 | Everything is changing, including yourself and the whole universe [Aurelius] |
10591 | Logicians use 'property' and 'set' interchangeably, with little hanging on it [Shapiro] |
299 | What is fine is always difficult [Plato] |
297 | What is fine is the parent of goodness [Plato] |
3066 | Nothing is evil which is according to nature [Aurelius] |
3071 | Justice has no virtue opposed to it, but pleasure has temperance opposed to it [Aurelius] |
3069 | The art of life is more like the wrestler's than the dancer's [Aurelius] |
3065 | Humans are naturally made for co-operation [Aurelius] |
298 | While sex is very pleasant, it should be in secret, as it looks contemptible [Plato] |