252 ideas
| 19066 | Philosophy aims to understand the world, through ordinary experience and science [Dummett] |
| 18450 | Philosophy has its own mode of death, by separating soul from body [Porphyry] |
| 10838 | To explain a concept, we need its purpose, not just its rules of usage [Dummett] |
| 6779 | Instrumentalists say distinctions between observation and theory vanish with ostensive definition [Bird] |
| 17621 | What matters in mathematics is its objectivity, not the existence of the objects [Dummett] |
| 9847 | A contextual definition permits the elimination of the expression by a substitution [Dummett] |
| 19067 | A successful proof requires recognition of truth at every step [Dummett] |
| 10837 | It is part of the concept of truth that we aim at making true statements [Dummett] |
| 10840 | We must be able to specify truths in a precise language, like winning moves in a game [Dummett] |
| 19171 | Tarski's truth is like rules for winning games, without saying what 'winning' means [Dummett, by Davidson] |
| 8166 | Truth is part of semantics, since valid inference preserves truth [Dummett] |
| 19053 | Logic would be more natural if negation only referred to predicates [Dummett] |
| 19060 | Truth-tables are dubious in some cases, and may be a bad way to explain connective meaning [Dummett] |
| 16951 | It was realised that possible worlds covered all modal logics, if they had a structure [Dummett] |
| 16953 | Relative possibility one way may be impossible coming back, so it isn't symmetrical [Dummett] |
| 16952 | If something is only possible relative to another possibility, the possibility relation is not transitive [Dummett] |
| 16960 | If possibilitiy is relative, that might make accessibility non-transitive, and T the correct system [Dummett] |
| 16958 | In S4 the actual world has a special place [Dummett] |
| 9449 | The plausible Barcan formula implies modality in the actual world [Bird] |
| 18073 | Dummett says classical logic rests on meaning as truth, while intuitionist logic rests on assertability [Dummett, by Kitcher] |
| 18832 | Mathematical statements and entities that result from an infinite process must lack a truth-value [Dummett] |
| 10537 | The ordered pairs <x,y> can be reduced to the class of sets of the form {{x},{x,y}} [Dummett] |
| 9193 | ZF set theory has variables which range over sets, 'equals' and 'member', and extensionality [Dummett] |
| 9194 | The main alternative to ZF is one which includes looser classes as well as sets [Dummett] |
| 10542 | To associate a cardinal with each set, we need the Axiom of Choice to find a representative [Dummett] |
| 11066 | Deduction is justified by the semantics of its metalanguage [Dummett, by Hanna] |
| 9820 | In classical logic, logical truths are valid formulas; in higher-order logics they are purely logical [Dummett] |
| 19058 | Syntactic consequence is positive, for validity; semantic version is negative, with counterexamples [Dummett] |
| 8173 | Language can violate bivalence because of non-referring terms or ill-defined predicates [Dummett] |
| 8195 | Undecidable statements result from quantifying over infinites, subjunctive conditionals, and the past tense [Dummett] |
| 7334 | Anti-realism needs an intuitionist logic with no law of excluded middle [Dummett, by Miller,A] |
| 8179 | The law of excluded middle is the logical reflection of the principle of bivalence [Dummett] |
| 9195 | Intuitionists reject excluded middle, not for a third value, but for possibility of proof [Dummett] |
| 19052 | Natural language 'not' doesn't apply to sentences [Dummett] |
| 18801 | Classical negation is circular, if it relies on knowing negation-conditions from truth-conditions [Dummett] |
| 9182 | Ancient names like 'Obadiah' depend on tradition, not on where the name originated [Dummett] |
| 19057 | Classical quantification is an infinite conjunction or disjunction - but you may not know all the instances [Dummett] |
| 9186 | First-order logic concerns objects; second-order adds properties, kinds, relations and functions [Dummett] |
| 19063 | Beth trees show semantics for intuitionistic logic, in terms of how truth has been established [Dummett] |
| 19059 | In standard views you could replace 'true' and 'false' with mere 0 and 1 [Dummett] |
| 19062 | Classical two-valued semantics implies that meaning is grasped through truth-conditions [Dummett] |
| 9187 | Logical truths and inference are characterized either syntactically or semantically [Dummett] |
| 19065 | Soundness and completeness proofs test the theory of meaning, rather than the logic theory [Dummett] |
| 8194 | Surely there is no exact single grain that brings a heap into existence [Dummett] |
| 9896 | A prime number is one which is measured by a unit alone [Dummett] |
| 18255 | Addition of quantities is prior to ordering, as shown in cyclic domains like angles [Dummett] |
| 9191 | Ordinals seem more basic than cardinals, since we count objects in sequence [Dummett] |
| 9895 | A number is a multitude composed of units [Dummett] |
| 9852 | We understand 'there are as many nuts as apples' as easily by pairing them as by counting them [Dummett] |
| 15938 | Platonists ruin infinity, which is precisely a growing structure which is never completed [Dummett] |
| 10554 | Intuitionists find the Incompleteness Theorem unsurprising, since proof is intuitive, not formal [Dummett] |
| 9829 | The identity of a number may be fixed by something outside structure - by counting [Dummett] |
| 9828 | Numbers aren't fixed by position in a structure; it won't tell you whether to start with 0 or 1 [Dummett] |
| 9192 | The number 4 has different positions in the naturals and the wholes, with the same structure [Dummett] |
| 9876 | Set theory isn't part of logic, and why reduce to something more complex? [Dummett] |
| 15939 | For intuitionists it is constructed proofs (which take time) which make statements true [Dummett] |
| 10552 | Intuitionism says that totality of numbers is only potential, but is still determinate [Dummett] |
| 8190 | Intuitionists rely on the proof of mathematical statements, not their truth [Dummett] |
| 9501 | If all existents are causally active, that excludes abstracta and causally isolated objects [Bird] |
| 8198 | A 'Cambridge Change' is like saying 'the landscape changes as you travel east' [Dummett] |
| 9500 | If naturalism refers to supervenience, that leaves necessary entities untouched [Bird] |
| 10540 | We can't say that light is concrete but radio waves abstract [Dummett] |
| 10515 | Ostension is possible for concreta; abstracta can only be referred to via other objects [Dummett, by Hale] |
| 10544 | The concrete/abstract distinction seems crude: in which category is the Mistral? [Dummett] |
| 10546 | We don't need a sharp concrete/abstract distinction [Dummett] |
| 9884 | The distinction of concrete/abstract, or actual/non-actual, is a scale, not a dichotomy [Dummett] |
| 22297 | Dummett saw realism as acceptance of bivalence, rather than of mind-independent entities [Dummett, by Potter] |
| 9869 | Realism is just the application of two-valued semantics to sentences [Dummett] |
| 15049 | Metaphysical realists are committed to all unambiguous statements being true or not true [Dummett] |
| 8184 | Philosophers should not presume reality, but only invoke it when language requires it [Dummett] |
| 6780 | Anti-realism is more plausible about laws than about entities and theories [Bird] |
| 3303 | For anti-realists there are no natural distinctions between objects [Dummett, by Benardete,JA] |
| 8185 | We can't make sense of a world not apprehended by a mind [Dummett] |
| 8192 | I no longer think what a statement about the past says is just what can justify it [Dummett] |
| 8163 | Since 'no bird here' and 'no squirrel here' seem the same, we must talk of 'atomic' facts [Dummett] |
| 8161 | We know we can state facts, with true statements [Dummett] |
| 21628 | To say reality itself is vague is not properly intelligible [Dummett] |
| 8180 | 'That is red or orange' might be considered true, even though 'that is red' and 'that is orange' were not [Dummett] |
| 10548 | The context principle for names rules out a special philosophical sense for 'existence' [Dummett] |
| 10281 | The objects we recognise the world as containing depends on the structure of our language [Dummett] |
| 9502 | There might be just one fundamental natural property [Bird] |
| 9477 | Categorical properties are not modally fixed, but change across possible worlds [Bird] |
| 9490 | The categoricalist idea is that a property is only individuated by being itself [Bird] |
| 9495 | If we abstractly define a property, that doesn't mean some object could possess it [Bird] |
| 9492 | Categoricalists take properties to be quiddities, with no essential difference between them [Bird] |
| 9503 | To name an abundant property is either a Fregean concept, or a simple predicate [Bird] |
| 14540 | Only real powers are fundamental [Bird, by Mumford/Anjum] |
| 18451 | The presence of the incorporeal is only known by certain kinds of disposition [Porphyry] |
| 9450 | If all properties are potencies, and stimuli and manifestation characterise them, there is a regress [Bird] |
| 9498 | The essence of a potency involves relations, e.g. mass, to impressed force and acceleration [Bird] |
| 9474 | A disposition is finkish if a time delay might mean the manifestation fizzles out [Bird] |
| 9475 | A robust pot attached to a sensitive bomb is not fragile, but if struck it will easily break [Bird] |
| 9499 | Megarian actualists deny unmanifested dispositions [Bird] |
| 15034 | Are genera and species real or conceptual? bodies or incorporeal? in sensibles or separate from them? [Porphyry] |
| 10532 | We can understand universals by studying predication [Dummett] |
| 9486 | Why should a universal's existence depend on instantiation in an existing particular? [Bird] |
| 10534 | 'Nominalism' used to mean denial of universals, but now means denial of abstract objects [Dummett] |
| 9880 | Nominalism assumes unmediated mental contact with objects [Dummett] |
| 9472 | Resemblance itself needs explanation, presumably in terms of something held in common [Bird] |
| 10541 | Concrete objects such as sounds and smells may not be possible objects of ostension [Dummett] |
| 10545 | Abstract objects may not cause changes, but they can be the subject of change [Dummett] |
| 9885 | The existence of abstract objects is a pseudo-problem [Dummett] |
| 10555 | If we can intuitively apprehend abstract objects, this makes them observable and causally active [Dummett] |
| 9858 | Abstract objects nowadays are those which are objective but not actual [Dummett] |
| 10543 | Abstract objects must have names that fall within the range of some functional expression [Dummett] |
| 9859 | It is absurd to deny the Equator, on the grounds that it lacks causal powers [Dummett] |
| 9860 | 'We've crossed the Equator' has truth-conditions, so accept the Equator - and it's an object [Dummett] |
| 10320 | If a genuine singular term needs a criterion of identity, we must exclude abstract nouns [Dummett, by Hale] |
| 10547 | Abstract objects can never be confronted, and need verbal phrases for reference [Dummett] |
| 9872 | Abstract objects need the context principle, since they can't be encountered directly [Dummett] |
| 10531 | There is a modern philosophical notion of 'object', first introduced by Frege [Dummett] |
| 18459 | Diversity arises from the power of unity [Porphyry] |
| 9848 | Content is replaceable if identical, so replaceability can't define identity [Dummett, by Dummett] |
| 9842 | Frege introduced criteria for identity, but thought defining identity was circular [Dummett] |
| 9482 | If the laws necessarily imply p, that doesn't give a new 'nomological' necessity [Bird] |
| 9481 | Logical necessitation is not a kind of necessity; George Orwell not being Eric Blair is not a real possibility [Bird] |
| 6796 | Subjective probability measures personal beliefs; objective probability measures the chance of an event happening [Bird] |
| 6797 | Objective probability of tails measures the bias of the coin, not our beliefs about it [Bird] |
| 9505 | Empiricist saw imaginability and possibility as close, but now they seem remote [Bird] |
| 16957 | Possible worlds aren't how the world might be, but how a world might be, given some possibility [Dummett] |
| 16959 | If possible worlds have no structure (S5) they are equal, and it is hard to deny them reality [Dummett] |
| 9491 | Haecceitism says identity is independent of qualities and without essence [Bird] |
| 8199 | The existence of a universe without sentience or intelligence is an unintelligible fantasy [Dummett] |
| 8178 | Empirical and a priori knowledge are not distinct, but are extremes of a sliding scale [Dummett] |
| 18452 | Memory is not conserved images, but reproduction of previous thought [Porphyry] |
| 6800 | Many philosophers rate justification as a more important concept than knowledge [Bird] |
| 6786 | As science investigates more phenomena, the theories it needs decreases [Bird] |
| 6792 | If theories need observation, and observations need theories, how do we start? [Bird] |
| 6757 | Explanation predicts after the event; prediction explains before the event [Bird] |
| 6805 | Relativity ousted Newtonian mechanics despite a loss of simplicity [Bird] |
| 6777 | Realists say their theories involve truth and the existence of their phenomena [Bird] |
| 6804 | There is no agreement on scientific method - because there is no such thing [Bird] |
| 6778 | Instrumentalists regard theories as tools for prediction, with truth being irrelevant [Bird] |
| 6775 | Induction is inference to the best explanation, where the explanation is a law [Bird] |
| 6791 | If Hume is right about induction, there is no scientific knowledge [Bird] |
| 6790 | Anything justifying inferences from observed to unobserved must itself do that [Bird] |
| 6738 | Any conclusion can be drawn from an induction, if we use grue-like predicates [Bird] |
| 6739 | Several months of observing beech trees supports the deciduous and evergreen hypotheses [Bird] |
| 6799 | We normally learn natural kinds from laws, but Goodman shows laws require prior natural kinds [Bird] |
| 6798 | Bayesianism claims to find rationality and truth in induction, and show how science works [Bird] |
| 6752 | The objective component of explanations is the things that must exist for the explanation [Bird] |
| 6754 | We talk both of 'people' explaining things, and of 'facts' explaining things [Bird] |
| 9487 | We can't reject all explanations because of a regress; inexplicable A can still explain B [Bird] |
| 19061 | An explanation is often a deduction, but that may well beg the question [Dummett] |
| 6750 | Explanations are causal, nomic, psychological, psychoanalytic, Darwinian or functional [Bird] |
| 6761 | Contrastive explanations say why one thing happened but not another [Bird] |
| 6758 | 'Covering law' explanations only work if no other explanations are to be found [Bird] |
| 6759 | Livers always accompany hearts, but they don't explain hearts [Bird] |
| 6756 | Probabilistic-statistical explanations don't entail the explanandum, but makes it more likely [Bird] |
| 6760 | An operation might reduce the probability of death, yet explain a death [Bird] |
| 6785 | Inference to the Best Explanation is done with facts, so it has to be realist [Bird] |
| 6788 | Maybe bad explanations are the true ones, in this messy world [Bird] |
| 6787 | Which explanation is 'best' is bound to be subjective, and no guide to truth [Bird] |
| 6751 | Maybe explanation is so subjective that it cannot be a part of science [Bird] |
| 18453 | Intelligence is aware of itself, so the intelligence is both the thinker and the thought [Porphyry] |
| 18462 | The soul is everywhere and nowhere in the body, and must be its cause [Porphyry] |
| 17527 | Causation seems to be an innate concept (or acquired very early) [Bird] |
| 18463 | Successful introspection reveals the substrate along with the object of thought [Porphyry] |
| 18458 | The soul is bound to matter by the force of its own disposition [Porphyry] |
| 8174 | The theories of meaning and understanding are the only routes to an account of thought [Dummett] |
| 8175 | A theory of thought will include propositional attitudes as well as propositions [Dummett] |
| 19168 | Concepts only have a 'functional character', because they map to truth values, not objects [Dummett, by Davidson] |
| 9849 | Maybe a concept is 'prior' to another if it can be defined without the second concept [Dummett] |
| 9850 | An argument for conceptual priority is greater simplicity in explanation [Dummett] |
| 10839 | You can't infer a dog's abstract concepts from its behaviour [Dummett] |
| 9873 | Abstract terms are acceptable as long as we know how they function linguistically [Dummett] |
| 10549 | Since abstract objects cannot be picked out, we must rely on identity statements [Dummett] |
| 9993 | There is no reason why abstraction by equivalence classes should be called 'logical' [Dummett, by Tait] |
| 9857 | We arrive at the concept 'suicide' by comparing 'Cato killed Cato' with 'Brutus killed Brutus' [Dummett] |
| 9833 | To abstract from spoons (to get the same number as the forks), the spoons must be indistinguishable too [Dummett] |
| 8165 | To 'abstract from' is a logical process, as opposed to the old mental view [Dummett] |
| 19055 | Stating a sentence's truth-conditions is just paraphrasing the sentence [Dummett] |
| 19056 | If a sentence is effectively undecidable, we can never know its truth conditions [Dummett] |
| 8168 | To know the truth-conditions of a sentence, you must already know the meaning [Dummett] |
| 8193 | Verification is not an individual but a collective activity [Dummett] |
| 8181 | A justificationist theory of meaning leads to the rejection of classical logic [Dummett] |
| 8182 | Verificationism could be realist, if we imagined the verification by a superhuman power [Dummett] |
| 8183 | If truths about the past depend on memories and current evidence, the past will change [Dummett] |
| 19054 | Meaning as use puts use beyond criticism, and needs a holistic view of language [Dummett] |
| 8176 | We could only guess the meanings of 'true' and 'false' when sentences were used [Dummett] |
| 8170 | Sentences are the primary semantic units, because they can say something [Dummett] |
| 19064 | Holism is not a theory of meaning; it is the denial that a theory of meaning is possible [Dummett] |
| 10516 | A realistic view of reference is possible for concrete objects, but not for abstract objects [Dummett, by Hale] |
| 9181 | The causal theory of reference can't distinguish just hearing a name from knowing its use [Dummett] |
| 9836 | Fregean semantics assumes a domain articulated into individual objects [Dummett] |
| 8189 | Truth-condition theorists must argue use can only be described by appeal to conditions of truth [Dummett] |
| 8191 | The truth-conditions theory must get agreement on a conception of truth [Dummett] |
| 8169 | We can't distinguish a proposition from its content [Dummett] |
| 18464 | Justice is each person fulfilling his function [Porphyry] |
| 18448 | We should avoid the pleasures of love, or at least, should not enact our dreams [Porphyry] |
| 16956 | To explain generosity in a person, you must understand a generous action [Dummett] |
| 18444 | Civil virtues make us behave benevolently, and thereby unite citizens [Porphyry] |
| 18445 | Civil virtues control the passions, and make us conform to our nature [Porphyry] |
| 18446 | Purificatory virtues detach the soul completely from the passions [Porphyry] |
| 18447 | There are practical, purificatory, contemplative, and exemplary virtues [Porphyry] |
| 18456 | Unified real existence is neither great nor small, though greatness and smallness participate in it [Porphyry] |
| 6776 | Natural kinds are those that we use in induction [Bird] |
| 6767 | Rubies and sapphires are both corundum, with traces of metals varying their colours [Bird] |
| 6768 | Tin is not one natural kind, but appears to be 21, depending on isotope [Bird] |
| 6771 | Natural kinds may overlap, or be sub-kinds of one another [Bird] |
| 6770 | Membership of a purely random collection cannot be used as an explanation [Bird] |
| 6773 | If F is a universal appearing in a natural law, then Fs form a natural kind [Bird] |
| 6769 | In the Kripke-Putnam view only nuclear physicists can know natural kinds [Bird] |
| 6774 | Darwinism suggests that we should have a native ability to detect natural kinds [Bird] |
| 6764 | Nominal essence of a natural kind is the features that make it fit its name [Bird] |
| 6766 | Jadeite and nephrite are superficially identical, but have different composition [Bird] |
| 6808 | Reference to scientific terms is by explanatory role, not by descriptions [Bird] |
| 16954 | Generalised talk of 'natural kinds' is unfortunate, as they vary too much [Dummett] |
| 17528 | The dispositional account explains causation, as stimulation and manifestation of dispositions [Bird] |
| 9493 | We should explain causation by powers, not powers by causation [Bird] |
| 6753 | Laws are more fundamental in science than causes, and laws will explain causes [Bird] |
| 9494 | Singularism about causes is wrong, as the universals involved imply laws [Bird] |
| 17526 | The counterfactual approach makes no distinction between cause and pre-condition [Bird] |
| 6762 | Newton's laws cannot be confirmed individually, but only in combinations [Bird] |
| 6763 | Parapsychology is mere speculation, because it offers no mechanisms for its working [Bird] |
| 6772 | Existence requires laws, as inertia or gravity are needed for mass or matter [Bird] |
| 9507 | Laws are explanatory relationships of things, which supervene on their essences [Bird] |
| 9488 | Laws are either disposition regularities, or relations between properties [Bird] |
| 6746 | There may be many laws, each with only a few instances [Bird] |
| 6740 | 'All uranium lumps are small' is a law, but 'all gold lumps are small' is not [Bird] |
| 6741 | There can be remarkable uniformities in nature that are purely coincidental [Bird] |
| 6742 | A law might have no instances, if it was about things that only exist momentarily [Bird] |
| 6743 | If laws are just instances, the law should either have gaps, or join the instances arbitrarily [Bird] |
| 6744 | Where is the regularity in a law predicting nuclear decay? [Bird] |
| 6747 | Laws cannot explain instances if they are regularities, as something can't explain itself [Bird] |
| 6748 | Similar appearance of siblings is a regularity, but shared parents is what links them [Bird] |
| 6749 | We can only infer a true regularity if something binds the instances together [Bird] |
| 6803 | If we only infer laws from regularities among observations, we can't infer unobservable entities. [Bird] |
| 6801 | Accidental regularities are not laws, and an apparent regularity may not be actual [Bird] |
| 9496 | That other diamonds are hard does not explain why this one is [Bird] |
| 9479 | Dispositional essentialism says laws (and laws about laws) are guaranteed regularities [Bird] |
| 6745 | A regularity is only a law if it is part of a complete system which is simple and strong [Bird] |
| 6802 | With strange enough predicates, anything could be made out to be a regularity [Bird] |
| 9473 | Laws cannot offer unified explanations if they don't involve universals [Bird] |
| 9484 | If the universals for laws must be instantiated, a vanishing particular could destroy a law [Bird] |
| 9506 | Salt necessarily dissolves in water, because of the law which makes the existence of salt possible [Bird] |
| 23713 | Most laws supervene on fundamental laws, which are explained by basic powers [Bird, by Friend/Kimpton-Nye] |
| 6789 | If flame colour is characteristic of a metal, that is an empirical claim needing justification [Bird] |
| 9489 | Essentialism can't use conditionals to explain regularities, because of possible interventions [Bird] |
| 6807 | In Newton mass is conserved, but in Einstein it can convert into energy [Bird] |
| 18257 | Why should the limit of measurement be points, not intervals? [Dummett] |
| 9504 | The relational view of space-time doesn't cover times and places where things could be [Bird] |
| 18454 | Time is the circular movement of the soul [Porphyry] |
| 8186 | Time is the measure of change, so we can't speak of time before all change [Dummett] |
| 18455 | Some think time is seen at rest, as well as in movement [Porphyry] |
| 8197 | Maybe past (which affects us) and future (which we can affect) are both real [Dummett] |
| 8167 | If Presentism is correct, we cannot even say that the present changes [Dummett] |
| 8196 | The present cannot exist alone as a mere boundary; past and future truths are rendered meaningless [Dummett] |
| 18460 | God is nowhere, and hence everywhere [Porphyry] |
| 18461 | Everything existing proceeds from divinity, and is within divinity [Porphyry] |
| 18449 | Nature binds or detaches body to soul, but soul itself joins and detaches soul from body [Porphyry] |
| 18457 | Individual souls are all connected, though distinct, and without dividing universal Soul [Porphyry] |