227 ideas
9218 | Maybe what distinguishes philosophy from science is its pursuit of necessary truths [Sider] |
15209 | Like disastrous small errors in navigation, small misunderstandings can wreck intellectual life [Harré/Madden] |
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] |
15215 | Philosophy devises and assesses conceptual schemes in the service of worldviews [Harré/Madden] |
15003 | It seems unlikely that the way we speak will give insights into the universe [Sider] |
15212 | Analysis of concepts based neither on formalism nor psychology can arise from examining what we know [Harré/Madden] |
14986 | Conceptual analysts trust particular intuitions much more than general ones [Sider] |
15210 | Humeans see analysis in terms of formal logic, because necessities are fundamentally logical relations [Harré/Madden] |
15236 | Positivism says science only refers to immediate experiences [Harré/Madden] |
15227 | Logically, definitions have a subject, and a set of necessary predicates [Harré/Madden] |
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] |
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] |
13722 | A 'theorem' is an axiom, or the last line of a legitimate proof [Sider] |
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] |
15273 | Points can be 'dense' by unending division, but must meet a tougher criterion to be 'continuous' [Harré/Madden] |
15274 | Points are 'continuous' if any 'cut' point participates in both halves of the cut [Harré/Madden] |
13701 | A single second-order sentence validates all of arithmetic - but this can't be proved axiomatically [Sider] |
15211 | There is not an exclusive dichotomy between the formal and the logical [Harré/Madden] |
15261 | Humeans can only explain change with continuity as successive replacement [Harré/Madden] |
14760 | Four-dimensionalism sees things and processes as belonging in the same category [Sider] |
15268 | Humeans construct their objects from events, but we construct events from objects [Harré/Madden] |
15257 | The induction problem fades if you work with things, rather than with events [Harré/Madden] |
15017 | Supervenience is a modal connection [Sider] |
15300 | Fundamental particulars can't change [Harré/Madden] |
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] |
15319 | Hard individual blocks don't fix what 'things' are; fluids are no less material things [Harré/Madden] |
15014 | Unlike things, stuff obeys unrestricted composition and mereological essentialism [Sider] |
15320 | Magnetic and gravity fields can occupy the same place without merging [Harré/Madden] |
15318 | Gravitational and electrical fields are, for a materialist, distressingly empty of material [Harré/Madden] |
15267 | Events are changes in states of affairs (which consist of structured particulars, with powers and relations) [Harré/Madden] |
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] |
14978 | A property is intrinsic if an object alone in the world can instantiate it [Sider] |
15281 | Humeans see predicates as independent, but science says they are connected [Harré/Madden] |
14194 | Proper ontology should only use categorical (actual) properties, not hypothetical ones [Sider] |
14995 | Predicates can be 'sparse' if there is a universal, or if there is a natural property or relation [Sider] |
15279 | Energy was introduced to physics to refer to the 'store of potency' of a moving ball [Harré/Madden] |
15276 | Some powers need a stimulus, but others are just released [Harré/Madden] |
15305 | Some powers are variable, others cannot change (without destroying an identity) [Harré/Madden] |
15218 | Scientists define copper almost entirely (bar atomic number) in terms of its dispositions [Harré/Madden] |
15302 | We explain powers by the natures of things, but explanations end in inexplicable powers [Harré/Madden] |
15303 | Maybe a physical field qualifies as ultimate, if its nature is identical with its powers [Harré/Madden] |
15258 | Powers are not qualities; they just point to directions of empirical investigation [Harré/Madden] |
15315 | What is a field of potentials, if it only consists of possible events? [Harré/Madden] |
14745 | If sortal terms fix the kind and the persistence conditions, we need to know what kinds there are [Sider] |
15272 | The good criticism of substance by Humeans also loses them the vital concept of a thing [Harré/Madden] |
15304 | We can escape substance and its properties, if we take fields of pure powers as ultimate [Harré/Madden] |
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] |
14743 | The stage view of objects is best for dealing with coincident entities [Sider] |
15309 | The assumption that shape and solidity are fundamental implies dubious 'substance' in bodies [Harré/Madden] |
14747 | 'Composition as identity' says that an object just is the objects which compose it [Sider] |
15264 | The notorious substratum results from substance-with-qualities; individuals-with-powers solves this [Harré/Madden] |
15262 | In logic the nature of a kind, substance or individual is the essence which is inseparable from what it is [Harré/Madden] |
15297 | We can infer a new property of a thing from its other properties, via its essential nature [Harré/Madden] |
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] |
15266 | We say the essence of particles is energy, but only so we can tell a story about the nature of things [Harré/Madden] |
15220 | To say something remains the same but lacks its capacities and powers seems a contradiction [Harré/Madden] |
15222 | Some individuals can gain or lose capacities or powers, without losing their identity [Harré/Madden] |
15296 | A particular might change all of its characteristics, retaining mere numerical identity [Harré/Madden] |
14727 | Three-dimensionalists assert 'enduring', being wholly present at each moment, and deny 'temporal parts' [Sider] |
15275 | 'Dense' time raises doubts about continuous objects, so they need 'continuous' time [Harré/Madden] |
14738 | Some might say that its inconsistency with time travel is a reason to favour three-dimensionalism [Sider] |
15271 | If things are successive instantaneous events, nothing requires those events to resemble one another [Harré/Madden] |
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] |
14758 | How can an instantaneous stage believe anything, if beliefs take time? [Sider] |
14731 | Temporal parts are instantaneous [Sider] |
15256 | Humeans cannot step in the same river twice, because they cannot strictly form the concept of 'river' [Harré/Madden] |
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] |
15290 | What reduces the field of the possible is a step towards necessity [Harré/Madden] |
15291 | There is 'absolute' necessity (implied by all propositions) and 'relative' necessity (from what is given) [Harré/Madden] |
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] |
15230 | Logical necessity is grounded in the logical form of a statement [Harré/Madden] |
13709 | Logical truths must be necessary if anything is [Sider] |
15221 | The relation between what a thing is and what it can do or undergo relate by natural necessity [Harré/Madden] |
15214 | Natural necessity is not logical necessity or empirical contingency in disguise [Harré/Madden] |
15224 | A necessity corresponds to the nature of the actual [Harré/Madden] |
15232 | Natural necessity is when powerful particulars must produce certain results in a situation [Harré/Madden] |
15288 | People doubt science because if it isn't logically necessary it seems to be absolutely contingent [Harré/Madden] |
15289 | Property or event relations are naturally necessary if generated by essential mechanisms [Harré/Madden] |
15231 | Transcendental necessity is conditions of a world required for a rational being to know its nature [Harré/Madden] |
15234 | There is a transcendental necessity for each logical necessity, but the transcendental extends further [Harré/Madden] |
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] |
15260 | Counterfactuals are just right for analysing statements about the powers which things have [Harré/Madden] |
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] |
15233 | If natural necessity is used to include or exclude some predicate, the predicate is conceptually necessary [Harré/Madden] |
15028 | Conventionalism doesn't seem to apply to examples of the necessary a posteriori [Sider] |
15242 | Having a child is contingent for a 'man', necessary for a 'father'; the latter reflects a necessity of nature [Harré/Madden] |
15027 | If truths are necessary 'by convention', that seems to make them contingent [Sider] |
15216 | Is conceptual necessity just conventional, or does it mirror something about nature? [Harré/Madden] |
15235 | There is a conceptual necessity when properties become a standard part of a nominal essence [Harré/Madden] |
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] |
15228 | Necessity and contingency are separate from the a priori and the a posteriori [Harré/Madden] |
15252 | If Goldbach's Conjecture is true (and logically necessary), we may be able to conceive its opposite [Harré/Madden] |
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] |
15245 | It is silly to say that direct experience must be justified, either by reason, or by more experience [Harré/Madden] |
15244 | We experience qualities as of objects, not on their own [Harré/Madden] |
15248 | Inference in perception is unconvincingly defended as non-conscious and almost instantaneous [Harré/Madden] |
15269 | Humean impressions are too instantaneous and simple to have structure or relations [Harré/Madden] |
15286 | Clavius's Paradox: purely syntactic entailment theories won't explain, because they are too profuse [Harré/Madden] |
15283 | Simplicity can sort theories out, but still leaves an infinity of possibilities [Harré/Madden] |
15316 | The powers/natures approach has been so successful (for electricity, magnetism, gravity) it may be universal [Harré/Madden] |
15298 | We prefer the theory which explains and predicts the powers and capacities of particulars [Harré/Madden] |
14988 | A theory which doesn't fit nature is unexplanatory, even if it is true [Sider] |
15225 | Science investigates the nature and constitution of things or substances [Harré/Madden] |
14982 | If I used Ramsey sentences to eliminate fundamentality from my theory, that would be a real loss [Sider] |
15255 | Conjunctions explain nothing, and so do not give a reason for confidence in inductions [Harré/Madden] |
15270 | Hume's atomic events makes properties independent, and leads to problems with induction [Harré/Madden] |
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] |
15284 | Contraposition may be equivalent in truth, but not true in nature, because of irrelevant predicates [Harré/Madden] |
15285 | The items put forward by the contraposition belong within different natural clusters [Harré/Madden] |
15287 | The possibility that all ravens are black is a law depends on a mechanism producing the blackness [Harré/Madden] |
14990 | Bayes produces weird results if the prior probabilities are bizarre [Sider] |
15005 | Explanations must cite generalisations [Sider] |
15306 | Only changes require explanation [Harré/Madden] |
15293 | If explanation is by entailment, that lacks a causal direction, unlike natural necessity [Harré/Madden] |
15294 | Powers can explain the direction of causality, and make it a natural necessity [Harré/Madden] |
15254 | If the nature of particulars explains their powers, it also explains their relations and behaviour [Harré/Madden] |
15317 | Powers and natures lead us to hypothesise underlying mechanisms, which may be real [Harré/Madden] |
15310 | Solidity comes from the power of repulsion, and shape from the power of attraction [Harré/Madden] |
15219 | Essence explains passive capacities as well as active powers [Harré/Madden] |
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] |
15301 | The very concepts of a particular power or nature imply the possibility of being generalised [Harré/Madden] |
15226 | What properties a thing must have to be a type of substance can be laid down a priori [Harré/Madden] |
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] |
15229 | We say there is 'no alternative' in all sorts of contexts, and there are many different grounds for it [Harré/Madden] |
15292 | We can base the idea of a natural kind on the mechanisms that produce natural necessity [Harré/Madden] |
15299 | Species do not have enough constancy to be natural kinds [Harré/Madden] |
15253 | If the concept of a cause includes its usual effects, we call it a 'power' [Harré/Madden] |
15278 | Humean accounts of causal direction by time fail, because cause and effect can occur together [Harré/Madden] |
15246 | Active causal power is just objects at work, not something existing in itself [Harré/Madden] |
15213 | Causation always involves particular productive things [Harré/Madden] |
15217 | Efficient causes combine stimulus to individuals, absence of contraints on activity [Harré/Madden] |
15277 | The cause (or part of it) is what stimulates or releases the powerful particular thing involved [Harré/Madden] |
15237 | Originally Humeans based lawlike statements on pure qualities, without particulars [Harré/Madden] |
15238 | Being lawlike seems to resist formal analysis, because there are always counter-examples [Harré/Madden] |
15223 | Necessary effects will follow from some general theory specifying powers and structure of a world [Harré/Madden] |
15241 | Humeans say there is no necessity in causation, because denying an effect is never self-contradictory [Harré/Madden] |
15240 | In lawful universal statements (unlike accidental ones) we see why the regularity holds [Harré/Madden] |
15239 | We could call any generalisation a law, if it had reasonable support and no counter-evidence [Harré/Madden] |
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] |
15243 | We perceive motion, and not just successive occupations of different positions [Harré/Madden] |
14725 | Maybe motion is a dynamical quantity intrinsic to a thing at a particular time [Sider] |
15280 | 'Kinetic energy' is used to explain the effects of moving things when they are stopped [Harré/Madden] |
15265 | 'Energy' is a quasi-substance invented as the bearer of change during interactions [Harré/Madden] |
15321 | Space can't be an individual (in space), but it is present in all places [Harré/Madden] |
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] |
15263 | Chemistry is not purely structural; CO2 is not the same as SO2 [Harré/Madden] |
15259 | Chemical atoms have two powers: to enter certain combinations, and to emit a particular spectrum [Harré/Madden] |
1558 | Clearly the gods ignore human affairs, or they would have given us justice [Thrasymachus] |
15295 | Theism is supposed to make the world more intelligible - and should offer results [Harré/Madden] |