20 ideas
10301 | The axiom of choice is controversial, but it could be replaced [Shapiro] |
21695 | The set scheme discredited by paradoxes is actually the most natural one [Quine] |
21693 | Russell's antinomy challenged the idea that any condition can produce a set [Quine] |
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] |
10590 | Up Löwenheim-Skolem: if natural numbers satisfy wffs, then an infinite domain satisfies them [Shapiro] |
10296 | The Löwenheim-Skolem Theorems fail for second-order languages with standard semantics [Shapiro] |
10297 | The Löwenheim-Skolem theorem seems to be a defect of first-order logic [Shapiro] |
10292 | Downward Löwenheim-Skolem: if there's an infinite model, there is a countable model [Shapiro] |
21691 | Antinomies contradict accepted ways of reasoning, and demand revisions [Quine] |
21690 | Whenever the pursuer reaches the spot where the pursuer has been, the pursued has moved on [Quine] |
21689 | A barber shaves only those who do not shave themselves. So does he shave himself? [Quine] |
21694 | Membership conditions which involve membership and non-membership are paradoxical [Quine] |
21692 | If we write it as '"this sentence is false" is false', there is no paradox [Quine] |
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] |
7903 | The six perfections are giving, morality, patience, vigour, meditation, and wisdom [Nagarjuna] |