19 ideas
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] |
13152 | We can talk of 'innumerable number', about the infinite points on a line [Newton] |
13151 | Not all infinites are equal [Newton] |
10294 | Second-order logic has the expressive power for mathematics, but an unworkable model theory [Shapiro] |
10591 | Logicians use 'property' and 'set' interchangeably, with little hanging on it [Shapiro] |
6981 | Determinism clashes with free will, as the past determines action, and is beyond our control [Inwagen, by Jackson] |
15863 | The principles of my treatise are designed to fit with a belief in God [Newton] |
8340 | I do not pretend to know the cause of gravity [Newton] |
13150 | The motions of the planets could only derive from an intelligent agent [Newton] |
12178 | That gravity should be innate and essential to matter is absurd [Newton] |