20 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] |
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] |
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] |
8122 | True works of art transmit completely new feelings [Tolstoy] |
8121 | Art is when one man uses external signs to hand on his feelings to another man [Tolstoy] |
8124 | The highest feelings of mankind can only be transmitted by art [Tolstoy] |
8123 | The purpose of art is to help mankind to evolve better, more socially beneficial feelings [Tolstoy] |
22710 | People estimate art according to their moral values [Tolstoy] |
8125 | The upper classes put beauty first, and thus freed themselves from morality [Tolstoy] |
8064 | We separate the concept of beauty from goodness, unlike the ancients [Tolstoy] |
5655 | Happiness is not satisfaction of desires, but fulfilment of values [Bradley, by Scruton] |