189 ideas
| 1798 | He studied philosophy by suspending his judgement on everything [Pyrrho, by Diog. Laertius] |
| 9218 | Maybe what distinguishes philosophy from science is its pursuit of necessary truths [Sider] |
| 24069 | Much metaphysical debate concerns what is fundamental, rather than what exists [Koslicki] |
| 14721 | Metaphysical enquiry can survive if its conclusions are tentative [Sider] |
| 15010 | Your metaphysics is 'cheating' if your ontology won't support the beliefs you accept [Sider] |
| 14977 | Metaphysics is not about what exists or is true or essential; it is about the structure of reality [Sider] |
| 14994 | Extreme doubts about metaphysics also threaten to undermine the science of unobservables [Sider] |
| 15003 | It seems unlikely that the way we speak will give insights into the universe [Sider] |
| 14986 | Conceptual analysts trust particular intuitions much more than general ones [Sider] |
| 1800 | Sceptics say reason is only an instrument, because reason can only be attacked with reason [Pyrrho, by Diog. Laertius] |
| 17311 | Real definitions don't just single out a thing; they must also explain its essence [Koslicki] |
| 15118 | A successful Aristotelian 'definition' is what sciences produces after an investigation [Koslicki] |
| 15116 | Essences cause necessary features, and definitions describe those necessary features [Koslicki] |
| 14981 | Philosophical concepts are rarely defined, and are not understood by means of definitions [Sider] |
| 15015 | It seems possible for a correct definition to be factually incorrect, as in defining 'contact' [Sider] |
| 14992 | We don't care about plain truth, but truth in joint-carving terms [Sider] |
| 15012 | Orthodox truthmaker theories make entities fundamental, but that is poor for explanation [Sider] |
| 13689 | 'Theorems' are formulas provable from no premises at all [Sider] |
| 13705 | Truth tables assume truth functionality, and are just pictures of truth functions [Sider] |
| 13710 | In D we add that 'what is necessary is possible'; then tautologies are possible, and contradictions not necessary [Sider] |
| 13706 | Intuitively, deontic accessibility seems not to be reflexive, but to be serial [Sider] |
| 13711 | System B introduces iterated modalities [Sider] |
| 13708 | S5 is the strongest system, since it has the most valid formulas, because it is easy to be S5-valid [Sider] |
| 13712 | Epistemic accessibility is reflexive, and allows positive and negative introspection (KK and K¬K) [Sider] |
| 13714 | We can treat modal worlds as different times [Sider] |
| 13720 | Converse Barcan Formula: □∀αφ→∀α□φ [Sider] |
| 13718 | The Barcan Formula ∀x□Fx→□∀xFx may be a defect in modal logic [Sider] |
| 13723 | System B is needed to prove the Barcan Formula [Sider] |
| 15023 | The Barcan schema implies if X might have fathered something, there is something X might have fathered [Sider] |
| 13715 | You can employ intuitionist logic without intuitionism about mathematics [Sider] |
| 15004 | 'Gunk' is an object in which proper parts all endlessly have further proper parts [Sider] |
| 13258 | The 'aggregative' objections says mereology gets existence and location of objects wrong [Koslicki] |
| 14984 | Which should be primitive in mereology - part, or overlap? [Sider] |
| 14980 | There is a real issue over what is the 'correct' logic [Sider] |
| 15000 | 'It is raining' and 'it is not raining' can't be legislated, so we can't legislate 'p or ¬p' [Sider] |
| 15020 | Classical logic is good for mathematics and science, but less good for natural language [Sider] |
| 13680 | Maybe logical consequence is a primitive notion [Sider] |
| 13679 | Maybe logical consequence is more a matter of provability than of truth-preservation [Sider] |
| 13678 | The most popular account of logical consequence is the semantic or model-theoretic one [Sider] |
| 13682 | Maybe logical consequence is impossibility of the premises being true and the consequent false [Sider] |
| 15029 | Modal accounts of logical consequence are simple necessity, or essential use of logical words [Sider] |
| 13288 | Consequence is truth-preserving, either despite substitutions, or in all interpretations [Koslicki] |
| 13722 | A 'theorem' is an axiom, or the last line of a legitimate proof [Sider] |
| 14506 | 'Roses are red; therefore, roses are colored' seems truth-preserving, but not valid in a system [Koslicki] |
| 15019 | Define logical constants by role in proofs, or as fixed in meaning, or as topic-neutral [Sider] |
| 13696 | When a variable is 'free' of the quantifier, the result seems incapable of truth or falsity [Sider] |
| 13700 | A 'total' function must always produce an output for a given domain [Sider] |
| 13703 | λ can treat 'is cold and hungry' as a single predicate [Sider] |
| 13687 | No assumptions in axiomatic proofs, so no conditional proof or reductio [Sider] |
| 13688 | Good axioms should be indisputable logical truths [Sider] |
| 13691 | Induction has a 'base case', then an 'inductive hypothesis', and then the 'inductive step' [Sider] |
| 13690 | Proof by induction 'on the length of the formula' deconstructs a formula into its accepted atoms [Sider] |
| 15001 | 'Tonk' is supposed to follow the elimination and introduction rules, but it can't be so interpreted [Sider] |
| 13685 | Natural deduction helpfully allows reasoning with assumptions [Sider] |
| 13686 | We can build proofs just from conclusions, rather than from plain formulae [Sider] |
| 13697 | Valuations in PC assign truth values to formulas relative to variable assignments [Sider] |
| 13684 | The semantical notion of a logical truth is validity, being true in all interpretations [Sider] |
| 13704 | It is hard to say which are the logical truths in modal logic, especially for iterated modal operators [Sider] |
| 13724 | In model theory, first define truth, then validity as truth in all models, and consequence as truth-preservation [Sider] |
| 13698 | In a complete logic you can avoid axiomatic proofs, by using models to show consequences [Sider] |
| 13699 | Compactness surprisingly says that no contradictions can emerge when the set goes infinite [Sider] |
| 17435 | Objects do not naturally form countable units [Koslicki] |
| 17433 | We can still count squares, even if they overlap [Koslicki] |
| 17439 | There is no deep reason why we count carrots but not asparagus [Koslicki] |
| 17434 | We struggle to count branches and waves because our concepts lack clear boundaries [Koslicki] |
| 17312 | It is more explanatory if you show how a number is constructed from basic entities and relations [Koslicki] |
| 13701 | A single second-order sentence validates all of arithmetic - but this can't be proved axiomatically [Sider] |
| 14505 | Some questions concern mathematical entities, rather than whole structures [Koslicki] |
| 14760 | Four-dimensionalism sees things and processes as belonging in the same category [Sider] |
| 17314 | The relata of grounding are propositions or facts, but for dependence it is objects and their features [Koslicki] |
| 15017 | Supervenience is a modal connection [Sider] |
| 15008 | Is fundamentality in whole propositions (and holistic), or in concepts (and atomic)? [Sider] |
| 15013 | Tables and chairs have fundamental existence, but not fundamental natures [Sider] |
| 17436 | We talk of snow as what stays the same, when it is a heap or drift or expanse [Koslicki] |
| 15014 | Unlike things, stuff obeys unrestricted composition and mereological essentialism [Sider] |
| 15009 | We must distinguish 'concrete' from 'abstract' and necessary states of affairs. [Sider] |
| 13692 | A 'precisification' of a trivalent interpretation reduces it to a bivalent interpretation [Sider] |
| 13693 | A 'supervaluation' assigns further Ts and Fs, if they have been assigned in every precisification [Sider] |
| 13695 | Supervaluational logic is classical, except when it adds the 'Definitely' operator [Sider] |
| 13694 | We can 'sharpen' vague terms, and then define truth as true-on-all-sharpenings [Sider] |
| 14983 | Accept the ontology of your best theory - and also that it carves nature at the joints [Sider] |
| 13683 | A relation is a feature of multiple objects taken together [Sider] |
| 13289 | Structures have positions, constituent types and number, and some invariable parts [Koslicki] |
| 14978 | A property is intrinsic if an object alone in the world can instantiate it [Sider] |
| 14194 | Proper ontology should only use categorical (actual) properties, not hypothetical ones [Sider] |
| 14501 | 'Categorical' properties exist in the actual world, and 'hypothetical' properties in other worlds [Koslicki] |
| 14995 | Predicates can be 'sparse' if there is a universal, or if there is a natural property or relation [Sider] |
| 14745 | If sortal terms fix the kind and the persistence conditions, we need to know what kinds there are [Sider] |
| 14495 | I aim to put the notion of structure or form back into the concepts of part, whole and object [Koslicki] |
| 13264 | If a whole is just a structure, a dinner party wouldn't need the guests to turn up [Koslicki] |
| 24065 | Structured wholes are united by the teamwork needed for their capacities [Koslicki] |
| 14740 | If Tib is all of Tibbles bar her tail, when Tibbles loses her tail, two different things become one [Sider] |
| 14752 | Artists 'create' statues because they are essentially statues, and so lack identity with the lump of clay [Sider] |
| 14497 | The clay is just a part of the statue (its matter); the rest consists of its form or structure [Koslicki] |
| 13280 | Statue and clay differ in modal and temporal properties, and in constitution [Koslicki] |
| 14743 | The stage view of objects is best for dealing with coincident entities [Sider] |
| 24066 | The form explains kind, structure, unity and activity [Koslicki] |
| 14496 | Structure or form are right at the centre of modern rigorous modes of enquiry [Koslicki] |
| 14747 | 'Composition as identity' says that an object just is the objects which compose it [Sider] |
| 13279 | There are at least six versions of constitution being identity [Koslicki] |
| 14498 | For three-dimensionalist parthood must be a three-place relation, including times [Koslicki] |
| 13283 | The parts may be the same type as the whole, like a building made of buildings [Koslicki] |
| 13266 | Wholes in modern mereology are intended to replace sets, so they closely resemble them [Koslicki] |
| 14500 | Wholes are entities distinct from their parts, and have different properties [Koslicki] |
| 13281 | Wholes are not just their parts; a whole is an entity distinct from the proper parts [Koslicki] |
| 15110 | An essence and what merely follow from it are distinct [Koslicki] |
| 17313 | Modern views want essences just to individuate things across worlds and times [Koslicki] |
| 15113 | Individuals are perceived, but demonstration and definition require universals [Koslicki] |
| 24067 | Hylomorphic compounds need an individual form for transworld identity [Koslicki] |
| 17309 | For Fine, essences are propositions true because of identity, so they are just real definitions [Koslicki] |
| 17315 | We need a less propositional view of essence, and so must distinguish it clearly from real definitions [Koslicki] |
| 15112 | If an object exists, then its essential properties are necessary [Koslicki] |
| 14757 | Mereological essentialism says an object's parts are necessary for its existence [Sider] |
| 15026 | Essence (even if nonmodal) is not fundamental in metaphysics [Sider] |
| 14727 | Three-dimensionalists assert 'enduring', being wholly present at each moment, and deny 'temporal parts' [Sider] |
| 14738 | Some might say that its inconsistency with time travel is a reason to favour three-dimensionalism [Sider] |
| 14726 | Four-dimensionalists assert 'temporal parts', 'perduring', and being spread out over time [Sider] |
| 14728 | 4D says intrinsic change is difference between successive parts [Sider] |
| 14729 | 4D says each spatiotemporal object must have a temporal part at every moment at which it exists [Sider] |
| 14730 | Temporal parts exist, but are not prior building blocks for objects [Sider] |
| 14762 | Four-dimensionalism says temporal parts are caused (through laws of motion) by previous temporal parts [Sider] |
| 14731 | Temporal parts are instantaneous [Sider] |
| 14758 | How can an instantaneous stage believe anything, if beliefs take time? [Sider] |
| 14741 | The ship undergoes 'asymmetric' fission, where one candidate is seen as stronger [Sider] |
| 13702 | The identity of indiscernibles is necessarily true, if being a member of some set counts as a property [Sider] |
| 14754 | If you say Leibniz's Law doesn't apply to 'timebound' properties, you are no longer discussing identity [Sider] |
| 13721 | 'Strong' necessity in all possible worlds; 'weak' necessity in the worlds where the relevant objects exist [Sider] |
| 13707 | Maybe metaphysical accessibility is intransitive, if a world in which I am a frog is impossible [Sider] |
| 13709 | Logical truths must be necessary if anything is [Sider] |
| 13716 | 'If B hadn't shot L someone else would have' if false; 'If B didn't shoot L, someone else did' is true [Sider] |
| 15031 | Modal terms in English are entirely contextual, with no modality outside the language [Sider] |
| 15030 | Humeans say that we decide what is necessary [Sider] |
| 15028 | Conventionalism doesn't seem to apply to examples of the necessary a posteriori [Sider] |
| 15027 | If truths are necessary 'by convention', that seems to make them contingent [Sider] |
| 15033 | Humeans says mathematics and logic are necessary because that is how our concept of necessity works [Sider] |
| 15025 | The world does not contain necessity and possibility - merely how things are [Sider] |
| 13717 | Transworld identity is not a problem in de dicto sentences, which needn't identify an individual [Sider] |
| 14763 | Counterparts rest on similarity, so there are many such relations in different contexts [Sider] |
| 13719 | Barcan Formula problem: there might have been a ghost, despite nothing existing which could be a ghost [Sider] |
| 6595 | If we need a criterion of truth, we need to know whether it is the correct criterion [Pyrrho, by Fogelin] |
| 6593 | The Pyrrhonians attacked the dogmas of professors, not ordinary people [Pyrrho, by Fogelin] |
| 6592 | Academics said that Pyrrhonians were guilty of 'negative dogmatism' [Pyrrho, by Fogelin] |
| 1808 | Perception of things depends on their size or quantity (Mode 8) [Pyrrho, by Diog. Laertius] |
| 1801 | Animals vary in their feelings and judgements (Mode 1) [Pyrrho, by Diog. Laertius] |
| 1802 | Individuals vary in responses and feelings (Mode 2) [Pyrrho, by Diog. Laertius] |
| 1807 | Perception varies with viewing distance and angle (Mode 7) [Pyrrho, by Diog. Laertius] |
| 1805 | Judgements vary according to local culture and law (Mode 5) [Pyrrho, by Diog. Laertius] |
| 1809 | Perception is affected by expectations (Mode 9) [Pyrrho, by Diog. Laertius] |
| 1804 | Perception varies with madness or disease (Mode 4) [Pyrrho, by Diog. Laertius] |
| 1810 | Perception and judgement depend on comparison (Mode 10) [Pyrrho, by Diog. Laertius] |
| 1803 | Objects vary according to which sense perceives them (Mode 3) [Pyrrho, by Diog. Laertius] |
| 1806 | Perception of objects depends on surrounding conditions (Mode 6) [Pyrrho, by Diog. Laertius] |
| 15111 | In demonstration, the explanatory order must mirror the causal order of the phenomena [Koslicki] |
| 15115 | In a demonstration the middle term explains, by being part of the definition [Koslicki] |
| 14988 | A theory which doesn't fit nature is unexplanatory, even if it is true [Sider] |
| 14982 | If I used Ramsey sentences to eliminate fundamentality from my theory, that would be a real loss [Sider] |
| 14989 | Problem predicates in induction don't reflect the structure of nature [Sider] |
| 14997 | Two applications of 'grue' do not guarantee a similarity between two things [Sider] |
| 14990 | Bayes produces weird results if the prior probabilities are bizarre [Sider] |
| 15005 | Explanations must cite generalisations [Sider] |
| 17317 | A good explanation captures the real-world dependence among the phenomena [Koslicki] |
| 15117 | Greek uses the same word for 'cause' and 'explanation' [Koslicki] |
| 15114 | Discovering the Aristotelian essence of thunder will tell us why thunder occurs [Koslicki] |
| 15011 | If the ultimate explanation is a list of entities, no laws, patterns or mechanisms can be cited [Sider] |
| 15018 | Intentionality is too superficial to appear in the catalogue of ultimate physics [Sider] |
| 17316 | We can abstract to a dependent entity by blocking out features of its bearer [Koslicki] |
| 14999 | Prior to conventions, not all green things were green? [Sider] |
| 14998 | Conventions are contingent and analytic truths are necessary, so that isn't their explanation [Sider] |
| 15016 | Analyticity has lost its traditional role, which relied on truth by convention [Sider] |
| 14504 | The Kripke/Putnam approach to natural kind terms seems to give them excessive stability [Koslicki] |
| 13285 | Natural kinds support inductive inferences, from previous samples to the next one [Koslicki] |
| 13287 | Concepts for species are either intrinsic structure, or relations like breeding or ancestry [Koslicki] |
| 13284 | Should vernacular classifications ever be counted as natural kind terms? [Koslicki] |
| 3062 | There are no causes, because they are relative, and alike things can't cause one another [Pyrrho, by Diog. Laertius] |
| 14987 | Many of the key theories of modern physics do not appear to be 'laws' [Sider] |
| 14985 | The notion of law doesn't seem to enhance physical theories [Sider] |
| 13286 | There are apparently no scientific laws concerning biological species [Koslicki] |
| 3063 | Motion can't move where it is, and can't move where it isn't, so it can't exist [Pyrrho, by Diog. Laertius] |
| 14725 | Maybe motion is a dynamical quantity intrinsic to a thing at a particular time [Sider] |
| 14991 | Space has real betweenness and congruence structure (though it is not the Euclidean concepts) [Sider] |
| 15021 | The central question in the philosophy of time is: How alike are time and space? [Sider] |
| 14735 | Space is 3D and lacks a direction; time seems connected to causation [Sider] |
| 15024 | The spotlight theorists accepts eternal time, but with a spotlight of the present moving across it [Sider] |
| 14722 | Between presentism and eternalism is the 'growing block' view - the past is real, the future is not [Sider] |
| 14756 | For Presentists there must always be a temporal vantage point for any description [Sider] |
| 14724 | Presentists must deny truths about multiple times [Sider] |
| 14723 | Talk using tenses can be eliminated, by reducing it to indexical connections for an utterance [Sider] |
| 14734 | The B-series involves eternalism, and the reduction of tense [Sider] |
| 14736 | The B-theory is adequate, except that it omits to say which time is present [Sider] |