104 ideas
20910 | Everything happens necessarily, and for a reason [Democritus] |
10987 | Three traditional names of rules are 'Simplification', 'Addition' and 'Disjunctive Syllogism' [Read] |
11004 | Necessity is provability in S4, and true in all worlds in S5 [Read] |
11018 | There are fuzzy predicates (and sets), and fuzzy quantifiers and modifiers [Read] |
11011 | Same say there are positive, negative and neuter free logics [Read] |
11020 | Realisms like the full Comprehension Principle, that all good concepts determine sets [Read] |
14187 | If logic is topic-neutral that means it delves into all subjects, rather than having a pure subject matter [Read] |
10986 | Not all validity is captured in first-order logic [Read] |
10972 | The non-emptiness of the domain is characteristic of classical logic [Read] |
11024 | Semantics must precede proof in higher-order logics, since they are incomplete [Read] |
10985 | We should exclude second-order logic, precisely because it captures arithmetic [Read] |
14188 | Not all arguments are valid because of form; validity is just true premises and false conclusion being impossible [Read] |
14182 | If the logic of 'taller of' rests just on meaning, then logic may be the study of merely formal consequence [Read] |
14183 | Maybe arguments are only valid when suppressed premises are all stated - but why? [Read] |
10970 | A theory of logical consequence is a conceptual analysis, and a set of validity techniques [Read] |
10984 | Logical consequence isn't just a matter of form; it depends on connections like round-square [Read] |
14184 | In modus ponens the 'if-then' premise contributes nothing if the conclusion follows anyway [Read] |
14186 | Logical connectives contain no information, but just record combination relations between facts [Read] |
10973 | A theory is logically closed, which means infinite premisses [Read] |
11007 | Quantifiers are second-order predicates [Read] |
10978 | In second-order logic the higher-order variables range over all the properties of the objects [Read] |
10971 | A logical truth is the conclusion of a valid inference with no premisses [Read] |
10988 | Any first-order theory of sets is inadequate [Read] |
10975 | Compactness does not deny that an inference can have infinitely many premisses [Read] |
10974 | Compactness is when any consequence of infinite propositions is the consequence of a finite subset [Read] |
10977 | Compactness blocks the proof of 'for every n, A(n)' (as the proof would be infinite) [Read] |
10976 | Compactness makes consequence manageable, but restricts expressive power [Read] |
11014 | Self-reference paradoxes seem to arise only when falsity is involved [Read] |
16146 | Two can't be a self-contained unit, because it would need to be one to do that [Democritus, by Aristotle] |
11025 | Infinite cuts and successors seems to suggest an actual infinity there waiting for us [Read] |
10979 | Although second-order arithmetic is incomplete, it can fully model normal arithmetic [Read] |
10980 | Second-order arithmetic covers all properties, ensuring categoricity [Read] |
10997 | Von Neumann numbers are helpful, but don't correctly describe numbers [Read] |
20901 | True Being only occurs when it is completely full, with atoms and no void [Democritus, by Aristotle] |
20902 | Being does not exist more than non-being [Democritus, by Aristotle] |
20904 | The non-existent exists as much as the existent, because it has causal powers [Democritus] |
20903 | The only distinctions are Configuration (shape), Disposition (order) and Turning (position) [Democritus, by Aristotle] |
20893 | Nothing comes from non-existence, or passes into it [Democritus, by Diog. Laertius] |
11016 | Would a language without vagueness be usable at all? [Read] |
11019 | Supervaluations say there is a cut-off somewhere, but at no particular place [Read] |
11012 | A 'supervaluation' gives a proposition consistent truth-value for classical assignments [Read] |
11013 | Identities and the Indiscernibility of Identicals don't work with supervaluations [Read] |
20896 | It is not possible to know what sort each thing is [Democritus] |
10995 | A haecceity is a set of individual properties, essential to each thing [Read] |
3357 | Democritus denies reality to large objects, because atomic entities can't combine to produce new ones [Benardete,JA on Democritus] |
598 | Democritus said that substances could never be mixed, so atoms are the substances [Democritus, by Aristotle] |
11001 | Equating necessity with truth in every possible world is the S5 conception of necessity [Read] |
490 | Everything happens by reason and necessity [Leucippus] |
10989 | The standard view of conditionals is that they are truth-functional [Read] |
10992 | The point of conditionals is to show that one will accept modus ponens [Read] |
11017 | Some people even claim that conditionals do not express propositions [Read] |
14185 | Conditionals are just a shorthand for some proof, leaving out the details [Read] |
10983 | Knowledge of possible worlds is not causal, but is an ontology entailed by semantics [Read] |
10982 | How can modal Platonists know the truth of a modal proposition? [Read] |
10996 | Actualism is reductionist (to parts of actuality), or moderate realist (accepting real abstractions) [Read] |
10981 | A possible world is a determination of the truth-values of all propositions of a domain [Read] |
11000 | If worlds are concrete, objects can't be present in more than one, and can only have counterparts [Read] |
1532 | Sensible qualities can't be real if they appear different to different creatures [Democritus, by Theophrastus] |
20894 | Man is separated from reality [Democritus] |
517 | All evidence comes from senses, so they are indispensable to the mind [Democritus] |
20897 | Obscure knowledge belongs to the five senses, and genuine knowledge is the other type [Democritus] |
577 | Democritus says there is either no truth, or it is concealed from us [Democritus, by Aristotle] |
20895 | We actually know nothing, and opinions are mere flux [Democritus] |
1528 | We in fact know nothing, but we each restructure our reality with beliefs [Democritus] |
492 | It is obviously impossible to understand the reality of each thing [Democritus] |
515 | We know nothing in reality; for truth lies in an abyss [Democritus] |
20892 | Democritus was devoted to discovering causal explanations [Democritus, by Eusebius] |
5882 | Democritus says soul consists of smooth round bodies brought together in accidental collision [Democritus, by Cicero] |
6034 | Atomists say soul has a rational part in the chest, and a diffused non-rational part [Democritus, by Aetius] |
20912 | The soul is the same as the mind [Democritus, by Aristotle] |
20916 | Animals have a share of reason [Democritus, by Porphyry] |
20914 | The directive centre is located in the whole head [Democritus, by Ps-Plutarch] |
10998 | The mind abstracts ways things might be, which are nonetheless real [Read] |
6033 | Democritus said everything happens of necessity, by natural motion of atoms [Democritus, by Cicero] |
5088 | Some say there is a determinate cause for every apparently spontaneous event [Democritus, by Aristotle] |
21670 | Democritus said atoms only move by their natural motions, which are therefore necessary [Democritus, by Cicero] |
24041 | Democritus says spherical atoms are fire, and constitute the soul [psuche] [Democritus, by Aristotle] |
20913 | Democritus says the soul is the body, and thinking is thus the mixture of the body [Democritus, by Theophrastus] |
11005 | Negative existentials with compositionality make the whole sentence meaningless [Read] |
10966 | A proposition objectifies what a sentence says, as indicative, with secure references [Read] |
1540 | Pleasure and pain guide our choices of good and bad [Democritus] |
495 | Wisdom creates a healthy passion-free soul [Democritus] |
1537 | Happiness is identifying and separating the pleasures [Democritus, by Stobaeus] |
20917 | Contentment comes from moderation and proportion in life [Democritus, by Stobaeus] |
13551 | Democritus says wealth is a burden to the virtuous mind [Democritus, by Seneca] |
20899 | Atoms cling together, until a stronger necessity disperses them [Democritus, by Aristotle] |
20898 | Atoms are irregular, hooked, concave, convex, and many other shapes [Democritus, by Aristotle] |
17542 | 'Full' and 'Void' secularised Parmenides's Being and Not-being [Democritus, by Heisenberg] |
1525 | Atomists say there are only three differences - in shape, arrangement and position [Democritus, by Aristotle] |
493 | Experiences are merely convention; only atoms and the void are real [Democritus] |
5947 | If only atoms are real and the rest is convention, we wouldn't bother to avoid pain [Democritus, by Diogenes of Oen.] |
13219 | When atoms touch, why don't they coalesce, like water drops? [Aristotle on Democritus] |
1533 | Because appearance is infinitely varied, atomists assume infinitely many shapes of atom [Democritus, by Aristotle] |
20908 | There could be an atom the size of the world [Democritus, by Ps-Plutarch] |
1527 | There must be atoms, to avoid the absurdity of infinite division down to nothing [Democritus, by Aristotle] |
20909 | The basic atoms are without qualities - which only arise from encounters between atoms [Democritus, by Galen] |
1536 | If a cone is horizontally sliced the surfaces can't be equal, so it goes up in steps [Democritus] |
23314 | Greeks explained regularity by intellectual design, not by laws [Democritus, by Frede,M] |
20905 | Growth and movement would not exist if there were no void to receive them [Democritus] |
24059 | Democritus is wrong: in a void we wouldn't see a distant ant in exact detail [Aristotle on Democritus] |
5101 | Movement is impossible in a void, because nothing can decide the direction of movement [Aristotle on Democritus] |
20911 | There are unlimited worlds of varying sizes, some without life or water [Democritus, by Hippolytus] |
1535 | Democritus said people imagined gods as the source of what awed or frightened them [Democritus, by Sext.Empiricus] |
20915 | The soul is destroyed with the body [Democritus, by Ps-Plutarch] |