217 ideas
9199 | Wisdom for one instant is as good as wisdom for eternity [Chrysippus] |
20853 | Wise men should try to participate in politics, since they are a good influence [Chrysippus, by Diog. Laertius] |
20772 | Three branches of philosophy: first logic, second ethics, third physics (which ends with theology) [Chrysippus] |
5969 | Chrysippus said the uncaused is non-existent [Chrysippus, by Plutarch] |
21388 | The causes of future true events must exist now, so they will happen because of destiny [Chrysippus, by Cicero] |
20780 | Graspable presentations are criteria of facts, and are molded according to their objects [Chrysippus, by Diog. Laertius] |
20793 | How could you ever know that the presentation is similar to the object? [Sext.Empiricus on Chrysippus] |
8077 | Stoic propositional logic is like chemistry - how atoms make molecules, not the innards of atoms [Chrysippus, by Devlin] |
10987 | Three traditional names of rules are 'Simplification', 'Addition' and 'Disjunctive Syllogism' [Read] |
20791 | Chrysippus has five obvious 'indemonstrables' of reasoning [Chrysippus, by Diog. Laertius] |
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] |
8625 | What physical facts could underlie 0 or 1, or very large numbers? [Frege on Mill] |
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] |
8078 | Modus ponens is one of five inference rules identified by the Stoics [Chrysippus, by Devlin] |
6023 | Every proposition is either true or false [Chrysippus, by Cicero] |
14186 | Logical connectives contain no information, but just record combination relations between facts [Read] |
17895 | Combining two distinct assertions does not necessarily lead to a single 'complex proposition' [Mill] |
10973 | A theory is logically closed, which means infinite premisses [Read] |
10427 | All names are names of something, real or imaginary [Mill] |
4944 | Mill says names have denotation but not connotation [Mill, by Kripke] |
7762 | Proper names are just labels for persons or objects, and the meaning is the object [Mill, by Lycan] |
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] |
9801 | Numbers must be assumed to have identical units, as horses are equalised in 'horse-power' [Mill] |
11025 | Infinite cuts and successors seems to suggest an actual infinity there waiting for us [Read] |
8742 | The only axioms needed are for equality, addition, and successive numbers [Mill, by Shapiro] |
10980 | Second-order arithmetic covers all properties, ensuring categoricity [Read] |
10979 | Although second-order arithmetic is incomplete, it can fully model normal arithmetic [Read] |
9800 | Arithmetic is based on definitions, and Sums of equals are equal, and Differences of equals are equal [Mill] |
10997 | Von Neumann numbers are helpful, but don't correctly describe numbers [Read] |
5201 | Mill says logic and maths is induction based on a very large number of instances [Mill, by Ayer] |
9360 | If two black and two white objects in practice produced five, what colour is the fifth one? [Lewis,CI on Mill] |
9888 | Mill mistakes particular applications as integral to arithmetic, instead of general patterns [Dummett on Mill] |
9796 | Things possess the properties of numbers, as quantity, and as countable parts [Mill] |
9794 | There are no such things as numbers in the abstract [Mill] |
9795 | Numbers have generalised application to entities (such as bodies or sounds) [Mill] |
9798 | Different parcels made from three pebbles produce different actual sensations [Mill] |
9797 | '2 pebbles and 1 pebble' and '3 pebbles' name the same aggregation, but different facts [Mill] |
9799 | 3=2+1 presupposes collections of objects ('Threes'), which may be divided thus [Mill] |
9803 | We can't easily distinguish 102 horses from 103, but we could arrange them to make it obvious [Mill] |
9802 | Numbers denote physical properties of physical phenomena [Mill] |
9804 | Arithmetical results give a mode of formation of a given number [Mill] |
9805 | 12 is the cube of 1728 means pebbles can be aggregated a certain way [Mill] |
8741 | Numbers must be of something; they don't exist as abstractions [Mill] |
12411 | Mill is too imprecise, and is restricted to simple arithmetic [Kitcher on Mill] |
5656 | Empirical theories of arithmetic ignore zero, limit our maths, and need probability to get started [Frege on Mill] |
9624 | Numbers are a very general property of objects [Mill, by Brown,JR] |
5992 | Chrysippus says action is the criterion for existence, which must be physical [Chrysippus, by Tieleman] |
21673 | There are simple and complex facts; the latter depend on further facts [Chrysippus, by Cicero] |
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] |
16652 | Stoics categories are Substrate, Quality, Disposition, and Relation [Chrysippus, by Pasnau] |
10995 | A haecceity is a set of individual properties, essential to each thing [Read] |
16058 | Dion and Theon coexist, but Theon lacks a foot. If Dion loses a foot, he ousts Theon? [Chrysippus, by Philo of Alexandria] |
9806 | Whatever is made up of parts is made up of parts of those parts [Mill] |
11156 | The essence is that without which a thing can neither be, nor be conceived to be [Mill] |
16059 | Change of matter doesn't destroy identity - in Dion and Theon change is a condition of identity [Chrysippus, by Long/Sedley] |
12190 | Necessity is what will be, despite any alternative suppositions whatever [Mill] |
22623 | Necessity can only mean what must be, without conditions of any kind [Mill] |
11001 | Equating necessity with truth in every possible world is the S5 conception of necessity [Read] |
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] |
3583 | External objects are permanent possibilities of sensation [Mill] |
16859 | Most perception is one-tenth observation and nine-tenths inference [Mill] |
9082 | Clear concepts result from good observation, extensive experience, and accurate memory [Mill] |
16860 | Inductive generalisation is more reliable than one of its instances; they can't all be wrong [Mill] |
16843 | Mill's methods (Difference,Agreement,Residues,Concomitance,Hypothesis) don't nail induction [Mill, by Lipton] |
16845 | The whole theory of induction rests on causes [Mill] |
17086 | Surprisingly, empiricists before Mill ignore explanation, which seems to transcend experience [Mill, by Ruben] |
17091 | Explanation is fitting of facts into ever more general patterns of regularity [Mill, by Ruben] |
16805 | Causal inference is by spotting either Agreements or Differences [Mill, by Lipton] |
16835 | The Methods of Difference and of Agreement are forms of inference to the best explanation [Mill, by Lipton] |
3537 | I judge others' feeling by analogy with my body and behaviour [Mill] |
1875 | Dogs show reason in decisions made by elimination [Chrysippus, by Sext.Empiricus] |
9079 | We can focus our minds on what is common to a whole class, neglecting other aspects [Mill] |
10998 | The mind abstracts ways things might be, which are nonetheless real [Read] |
9081 | We don't recognise comparisons by something in our minds; the concepts result from the comparisons [Mill] |
20834 | Chrysippus allows evil to say it is fated, or even that it is rational and natural [Plutarch on Chrysippus] |
20833 | A swerve in the atoms would be unnatural, like scales settling differently for no reason [Chrysippus, by Plutarch] |
20808 | Everything is fated, either by continuous causes or by a supreme rational principle [Chrysippus, by Diog. Laertius] |
20835 | Chrysippus is wrong to believe in non-occurring future possibilities if he is a fatalist [Plutarch on Chrysippus] |
20836 | The Lazy Argument responds to fate with 'why bother?', but the bothering is also fated [Chrysippus, by Cicero] |
20837 | Fate is an eternal and fixed chain of causal events [Chrysippus] |
21679 | When we say events are fated by antecedent causes, do we mean principal or auxiliary causes? [Chrysippus] |
5971 | Destiny is only a predisposing cause, not a sufficient cause [Chrysippus, by Plutarch] |
9078 | The study of the nature of Abstract Ideas does not belong to logic, but to a different science [Mill] |
9080 | General conceptions are a necessary preliminary to Induction [Mill] |
11005 | Negative existentials with compositionality make the whole sentence meaningless [Read] |
20787 | A proposition is what can be asserted or denied on its own [Chrysippus] |
10966 | A proposition objectifies what a sentence says, as indicative, with secure references [Read] |
3772 | The will, in the beginning, is entirely produced by desire [Mill] |
20850 | Passions are judgements; greed thinks money is honorable, and likewise drinking and lust [Chrysippus, by Diog. Laertius] |
20869 | The highest degree of morality performs all that is appropriate, omitting nothing [Chrysippus] |
3044 | Stoics say that beauty and goodness are equivalent and linked [Chrysippus, by Diog. Laertius] |
20838 | Fate initiates general causes, but individual wills and characters dictate what we do [Chrysippus] |
7222 | It is a crime for someone with a violent disposition to get drunk [Mill] |
3769 | With early training, any absurdity or evil may be given the power of conscience [Mill] |
20813 | Human purpose is to contemplate and imitate the cosmos [Chrysippus] |
3045 | Stoics say justice is a part of nature, not just an invented principle [Chrysippus, by Diog. Laertius] |
20774 | Only nature is available to guide action and virtue [Chrysippus] |
20864 | Live in agreement, according to experience of natural events [Chrysippus] |
5972 | Living happily is nothing but living virtuously [Chrysippus, by Plutarch] |
1777 | Pleasure is not the good, because there are disgraceful pleasures [Chrysippus, by Diog. Laertius] |
5973 | Justice can be preserved if pleasure is a good, but not if it is the goal [Chrysippus, by Plutarch] |
3767 | Motive shows the worth of the agent, but not of the action [Mill] |
7076 | Mill wondered if he would be happy if all his aims were realised, and answered no [Mill, by Critchley] |
20845 | There are shameful pleasures, and nothing shameful is good, so pleasure is not a good [Chrysippus, by Diog. Laertius] |
5967 | People need nothing except corn and water [Chrysippus, by Plutarch] |
5966 | All virtue is good, but not always praised (as in not lusting after someone ugly) [Chrysippus] |
20855 | Chrysippus says virtue can be lost (though Cleanthes says it is too secure for that) [Chrysippus, by Diog. Laertius] |
5970 | Chrysippus says nothing is blameworthy, as everything conforms with the best nature [Chrysippus, by Plutarch] |
3771 | Virtues only have value because they achieve some further end [Mill] |
3768 | Orthodox morality is the only one which feels obligatory [Mill] |
3764 | Actions are right if they promote pleasure, wrong if they promote pain [Mill] |
3776 | Utilitarianism only works if everybody has a totally equal right to happiness [Mill] |
7214 | Ethics rests on utility, which is the permanent progressive interests of people [Mill] |
7202 | The English believe in the task of annihilating evil for the victory of good [Nietzsche on Mill] |
5935 | Mill's qualities of pleasure is an admission that there are other good states of mind than pleasure [Ross on Mill] |
3766 | Better to be Socrates dissatisfied than a fool satisfied [Mill] |
3763 | Ultimate goods such as pleasure can never be proved to be good [Mill] |
3765 | Only pleasure and freedom from pain are desirable as ends [Mill] |
3770 | General happiness is only desirable because individuals desire their own happiness [Mill] |
6697 | Moral rules protecting human welfare are more vital than local maxims [Mill] |
20842 | Rational animals begin uncorrupted, but externals and companions are bad influences [Chrysippus, by Diog. Laertius] |
7212 | Individuals have sovereignty over their own bodies and minds [Mill] |
3773 | No individual has the right to receive our benevolence [Mill] |
3774 | Rights are a matter of justice, not of benevolence [Mill] |
7210 | The will of the people is that of the largest or most active part of the people [Mill] |
7227 | It is evil to give a government any more power than is necessary [Mill] |
7228 | Individuals often do things better than governments [Mill] |
7230 | Aim for the maximum dissemination of power consistent with efficiency [Mill] |
20515 | Maximise happiness by an area of strict privacy, and an area of utilitarian interventions [Mill, by Wolff,J] |
7229 | People who transact their own business will also have the initiative to control their government [Mill] |
20508 | How people vote should be on public record, so they can be held accountable [Mill, by Wolff,J] |
20507 | Voting is a strict duty, like jury service, and must only be aimed at the public good [Mill] |
20505 | Direct democracy is inexperience judging experience, and ignorance judging knowledge [Mill] |
20504 | People can only participate in decisions in small communities, so representatives are needed [Mill] |
7211 | Prevention of harm to others is the only justification for exercising power over people [Mill] |
7231 | The worth of a State, in the long run, is the worth of the individuals composing it [Mill] |
7217 | The main argument for freedom is that interference with it is usually misguided [Mill] |
7213 | Liberty arises at the point where people can freely and equally discuss things [Mill] |
20517 | Utilitarianism values liberty, but guides us on which ones we should have or not have [Mill, by Wolff,J] |
20516 | Mill defends freedom as increasing happiness, but maybe it is an intrinsic good [Wolff,J on Mill] |
7215 | True freedom is pursuing our own good, while not impeding others [Mill] |
7218 | Individuals are not accountable for actions which only concern themselves [Mill] |
7221 | Blocking entry to an unsafe bridge does not infringe liberty, since no one wants unsafe bridges [Mill] |
7223 | Pimping and running a gambling-house are on the border between toleration and restraint [Mill] |
7220 | Restraint for its own sake is an evil [Mill] |
3775 | A right is a valid claim to society's protection [Mill] |
20856 | Justice, the law, and right reason are natural and not conventional [Chrysippus, by Diog. Laertius] |
7219 | Society can punish actions which it believes to be prejudicial to others [Mill] |
7226 | Benefits performed by individuals, not by government, help also to educate them [Mill] |
7224 | We need individual opinions and conduct, and State education is a means to prevent that [Mill] |
7225 | It is a crime to create a being who lacks the ordinary chances of a desirable existence [Mill] |
1779 | We don't have obligations to animals as they aren't like us [Chrysippus, by Diog. Laertius] |
20857 | Justice is irrelevant to animals, because they are too unlike us [Chrysippus, by Diog. Laertius] |
20812 | Covers are for shields, and sheaths for swords; likewise, all in the cosmos is for some other thing [Chrysippus] |
21403 | The later Stoics identified the logos with an air-fire compound, called 'pneuma' [Chrysippus, by Long] |
20828 | Fire is a separate element, not formed with others (as was previously believed) [Chrysippus, by Stobaeus] |
5975 | Stoics say earth, air, fire and water are the primary elements [Chrysippus, by Plutarch] |
8345 | A cause is the total of all the conditions which inevitably produce the result [Mill] |
10391 | Causes and conditions are not distinct, because we select capriciously from among them [Mill] |
14547 | The strict cause is the total positive and negative conditions which ensure the consequent [Mill] |
8377 | Causation is just invariability of succession between every natural fact and a preceding fact [Mill] |
14545 | A cause is an antecedent which invariably and unconditionally leads to a phenomenon [Mill] |
4773 | Mill's regularity theory of causation is based on an effect preceded by a conjunction of causes [Mill, by Psillos] |
4775 | In Mill's 'Method of Agreement' cause is the common factor in a range of different cases [Mill, by Psillos] |
4776 | In Mill's 'Method of Difference' the cause is what stops the effect when it is removed [Mill, by Psillos] |
9417 | What are the fewest propositions from which all natural uniformities could be inferred? [Mill] |
20819 | The past and the future subsist, but only the present exists [Chrysippus, by Plutarch] |
20818 | The present does not exist, so our immediate experience is actually part past and part future [Chrysippus, by Plutarch] |
20821 | Time is continous and infinitely divisible, so there cannot be a wholly present time [Chrysippus, by Stobaeus] |
3048 | Stoics say that God the creator is the perfection of all animals [Chrysippus, by Diog. Laertius] |
20773 | The origin of justice can only be in Zeus, and in nature [Chrysippus] |
3042 | Stoics teach that law is identical with right reason, which is the will of Zeus [Chrysippus, by Diog. Laertius] |
5965 | The source of all justice is Zeus and the universal nature [Chrysippus] |
21332 | We don't get a love of 'order' from nature - which is thoroughly chaotic [Mill] |
1782 | Stoics teach that God is a unity, variously known as Mind, or Fate, or Jupiter [Chrysippus, by Diog. Laertius] |
7216 | The ethics of the Gospel has been supplemented by barbarous Old Testament values [Mill] |
20830 | Death can't separate soul from body, because incorporeal soul can't unite with body [Chrysippus] |
21335 | Belief that an afterlife is required for justice is an admission that this life is very unjust [Mill] |
21334 | No necessity ties an omnipotent Creator, so he evidently wills human misery [Mill] |
21333 | Evil comes from good just as often as good comes from evil [Mill] |
21404 | There is a rationale in terrible disasters; they are useful to the whole, and make good possible [Chrysippus] |
21329 | Nature dispenses cruelty with no concern for either mercy or justice [Mill] |
21328 | Killing is a human crime, but nature kills everyone, and often with great tortures [Mill] |
21331 | Hurricanes, locusts, floods and blight can starve a million people to death [Mill] |
21330 | Nature makes childbirth a miserable experience, often leading to the death of the mother [Mill] |