37 ideas
3656 | The greatest good for a state is true philosophers [Descartes] |
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] |
16744 | All powers can be explained by obvious features like size, shape and motion of matter [Descartes] |
5016 | Five universals: genus, species, difference, property, accident [Descartes] |
5015 | A universal is a single idea applied to individual things that are similar to one another [Descartes] |
16630 | If we perceive an attribute, we infer the existence of some substance [Descartes] |
5013 | A substance needs nothing else in order to exist [Descartes] |
16633 | A substance has one principal property which is its nature and essence [Descartes] |
3658 | Total doubt can't include your existence while doubting [Descartes] |
5005 | I think, therefore I am, because for a thinking thing to not exist is a contradiction [Descartes] |
5006 | 'Thought' is all our conscious awareness, including feeling as well as understanding [Descartes] |
5012 | 'Nothing comes from nothing' is an eternal truth found within the mind [Descartes] |
5004 | We can know basic Principles without further knowledge, but not the other way round [Descartes] |
5014 | We can understand thinking occuring without imagination or sensation [Descartes] |
5017 | In thinking we shut ourselves off from other substances, showing our identity and separateness [Descartes] |
5010 | Our free will is so self-evident to us that it must be a basic innate idea [Descartes] |
5011 | There are two ultimate classes of existence: thinking substance and extended substance [Descartes] |
5018 | Even if tightly united, mind and body are different, as God could separate them [Descartes] |
5007 | Most errors of judgement result from an inaccurate perception of the facts [Descartes] |
5009 | We do not praise the acts of an efficient automaton, as their acts are necessary [Descartes] |
5008 | The greatest perfection of man is to act by free will, and thus merit praise or blame [Descartes] |
13304 | Learned men gain more in one day than others do in a lifetime [Posidonius] |
15987 | Physics only needs geometry or abstract mathematics, which can explain and demonstrate everything [Descartes] |
12730 | We will not try to understand natural or divine ends, or final causes [Descartes] |
16601 | Matter is not hard, heavy or coloured, but merely extended in space [Descartes] |
20820 | Time is an interval of motion, or the measure of speed [Posidonius, by Stobaeus] |