264 ideas
9218 | Maybe what distinguishes philosophy from science is its pursuit of necessary truths [Sider] |
14721 | Metaphysical enquiry can survive if its conclusions are tentative [Sider] |
16395 | Kripke separated semantics from metaphysics, rather than linking them, making the latter independent [Kripke, by Stalnaker] |
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] |
17034 | Analyses of concepts using entirely different terms are very inclined to fail [Kripke] |
14986 | Conceptual analysts trust particular intuitions much more than general ones [Sider] |
4955 | Some definitions aim to fix a reference rather than give a meaning [Kripke] |
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] |
15327 | Kripke's semantic theory has actually inspired promising axiomatic theories [Kripke, by Horsten] |
15343 | Kripke offers a semantic theory of truth (involving models) [Kripke, by Horsten] |
14966 | The Tarskian move to a metalanguage may not be essential for truth theories [Kripke, by Gupta] |
14967 | Certain three-valued languages can contain their own truth predicates [Kripke, by Gupta] |
16328 | Kripke classified fixed points, and illuminated their use for clarifications [Kripke, by Halbach] |
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] |
10163 | Propositional modal logic has been proved to be complete [Kripke, by Feferman/Feferman] |
10559 | Kripke's modal semantics presupposes certain facts about possible worlds [Kripke, by Zalta] |
16985 | Possible worlds allowed the application of set-theoretic models to modal logic [Kripke] |
10760 | With possible worlds, S4 and S5 are sound and complete, but S1-S3 are not even sound [Kripke, by Rossberg] |
13706 | Intuitively, deontic accessibility seems not to be reflexive, but to be serial [Sider] |
13710 | In D we add that 'what is necessary is possible'; then tautologies are possible, and contradictions not necessary [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] |
16189 | The variable domain approach to quantified modal logic invalidates the Barcan Formula [Kripke, by Simchen] |
15132 | The Barcan formulas fail in models with varying domains [Kripke, by Williamson] |
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] |
13678 | The most popular account of logical consequence is the semantic or model-theoretic one [Sider] |
13679 | Maybe logical consequence is more a matter of provability than of truth-preservation [Sider] |
13682 | Maybe logical consequence is impossibility of the premises being true and the consequent false [Sider] |
13680 | Maybe logical consequence is a primitive notion [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] |
10437 | Names are rigid, making them unlike definite descriptions [Kripke, by Sainsbury] |
4949 | Names are rigid designators, which designate the same object in all possible worlds [Kripke] |
4951 | A bundle of qualities is a collection of abstractions, so it can't be a particular [Kripke] |
17031 | A name can still refer even if it satisfies none of its well-known descriptions [Kripke] |
9175 | We may fix the reference of 'Cicero' by a description, but thereafter the name is rigid [Kripke] |
8957 | Some references, such as 'Neptune', have to be fixed by description rather than baptism [Kripke, by Szabó] |
9171 | The function of names is simply to refer [Kripke] |
10428 | Proper names must have referents, because they are not descriptive [Kripke, by Sainsbury] |
4959 | A name's reference is not fixed by any marks or properties of the referent [Kripke] |
16982 | A man has two names if the historical chains are different - even if they are the same! [Kripke] |
13703 | λ can treat 'is cold and hungry' as a single predicate [Sider] |
10792 | The substitutional quantifier is not in competition with the standard interpretation [Kripke, by Marcus (Barcan)] |
13688 | Good axioms should be indisputable logical truths [Sider] |
13687 | No assumptions in axiomatic proofs, so no conditional proof or reductio [Sider] |
13690 | Proof by induction 'on the length of the formula' deconstructs a formula into its accepted atoms [Sider] |
13691 | Induction has a 'base case', then an 'inductive hypothesis', and then the 'inductive step' [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] |
6007 | If you know your father, but don't recognise your father veiled, you know and don't know the same person [Eubulides, by Dancy,R] |
6006 | If you say truly that you are lying, you are lying [Eubulides, by Dancy,R] |
6008 | Removing one grain doesn't destroy a heap, so a heap can't be destroyed [Eubulides, by Dancy,R] |
13701 | A single second-order sentence validates all of arithmetic - but this can't be proved axiomatically [Sider] |
14760 | Four-dimensionalism sees things and processes as belonging in the same category [Sider] |
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] |
15014 | Unlike things, stuff obeys unrestricted composition and mereological essentialism [Sider] |
14896 | Kripke's metaphysics (essences, kinds, rigidity) blocks the slide into sociology [Kripke, by Ladyman/Ross] |
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] |
13695 | Supervaluational logic is classical, except when it adds the 'Definitely' operator [Sider] |
13693 | A 'supervaluation' assigns further Ts and Fs, if they have been assigned in every precisification [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] |
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] |
17000 | We might fix identities for small particulars, but it is utopian to hope for such things [Kripke] |
17647 | Kripke individuates objects by essential modal properties (and presupposes essentialism) [Kripke, by Putnam] |
14745 | If sortal terms fix the kind and the persistence conditions, we need to know what kinds there are [Sider] |
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] |
14747 | 'Composition as identity' says that an object just is the objects which compose it [Sider] |
16995 | Given that a table is made of molecules, could it not be molecular and still be this table? [Kripke] |
17047 | If we imagine this table made of ice or different wood, we are imagining a different table [Kripke] |
11868 | A different piece of wood could have been used for that table; constitution isn't identity [Wiggins on Kripke] |
5450 | For Kripke, essence is origin; for Putnam, essence is properties; for Wiggins, essence is membership of a kind [Kripke, by Mautner] |
17055 | Atomic number 79 is part of the nature of the gold we know [Kripke] |
16997 | An essential property is true of an object in any case where it would have existed [Kripke] |
17045 | De re modality is an object having essential properties [Kripke] |
17030 | Important properties of an object need not be essential to it [Kripke] |
16955 | Kripke says internal structure fixes species; I say it is genetic affinity and a common descent [Kripke, by Dummett] |
16996 | Given that Nixon is indeed a human being, that he might not have been does not concern knowledge [Kripke] |
14757 | Mereological essentialism says an object's parts are necessary for its existence [Sider] |
13971 | Kripke claims that some properties, only knowable posteriori, are known a priori to be essential [Kripke, by Soames] |
12100 | An essence is the necessary properties, derived from an intuitive identity, in origin, type and material [Kripke, by Witt] |
15026 | Essence (even if nonmodal) is not fundamental in metaphysics [Sider] |
16991 | No one seems to know the identity conditions for a material object (or for people) over time [Kripke] |
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] |
14731 | Temporal parts are instantaneous [Sider] |
14758 | How can an instantaneous stage believe anything, if beliefs take time? [Sider] |
14762 | Four-dimensionalism says temporal parts are caused (through laws of motion) by previous temporal parts [Sider] |
14741 | The ship undergoes 'asymmetric' fission, where one candidate is seen as stronger [Sider] |
11867 | If we lose track of origin, how do we show we are maintaining a reference? [Kripke, by Wiggins] |
12018 | Kripke argues, of the Queen, that parents of an organism are essentially so [Kripke, by Forbes,G] |
17046 | Could the actual Queen have been born of different parents? [Kripke] |
8274 | Socrates can't have a necessary origin, because he might have had no 'origin' [Lowe on Kripke] |
16981 | With the necessity of self-identity plus Leibniz's Law, identity has to be an 'internal' relation [Kripke] |
17044 | A relation can clearly be reflexive, and identity is the smallest reflexive relation [Kripke] |
17036 | Identity statements can be contingent if they rely on descriptions [Kripke] |
17038 | If Hesperus and Phosophorus are the same, they can't possibly be different [Kripke] |
13702 | The identity of indiscernibles is necessarily true, if being a member of some set counts as a property [Sider] |
4942 | The indiscernibility of identicals is as self-evident as the law of contradiction [Kripke] |
14754 | If you say Leibniz's Law doesn't apply to 'timebound' properties, you are no longer discussing identity [Sider] |
16999 | A vague identity may seem intransitive, and we might want to talk of 'counterparts' [Kripke] |
11880 | Kripke says his necessary a posteriori examples are known a priori to be necessary [Kripke, by Mackie,P] |
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] |
17037 | Physical necessity may be necessity in the highest degree [Kripke] |
17058 | What many people consider merely physically necessary I consider completely necessary [Kripke] |
4797 | Instead of being regularities, maybe natural laws are the weak a posteriori necessities of Kripke [Kripke, by Psillos] |
4970 | What is often held to be mere physical necessity is actually metaphysical necessity [Kripke] |
17059 | Unicorns are vague, so no actual or possible creature could count as a unicorn [Kripke] |
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] |
16984 | I don't think possible worlds reductively reveal the natures of modal operators etc. [Kripke] |
15030 | Humeans say that we decide what is necessary [Sider] |
15031 | Modal terms in English are entirely contextual, with no modality outside the language [Sider] |
15027 | If truths are necessary 'by convention', that seems to make them contingent [Sider] |
15028 | Conventionalism doesn't seem to apply to examples of the necessary a posteriori [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] |
4728 | Kripke separates necessary and a priori, proposing necessary a posteriori and contingent a priori examples [Kripke, by O'Grady] |
16990 | A priori = Necessary because we imagine all worlds, and we know without looking at actuality? [Kripke] |
9386 | The meter is defined necessarily, but the stick being one meter long is contingent a priori [Kripke] |
9385 | The very act of designating of an object with properties gives knowledge of a contingent truth [Kripke] |
4960 | "'Hesperus' is 'Phosphorus'" is necessarily true, if it is true, but not known a priori [Kripke] |
4966 | Theoretical identities are between rigid designators, and so are necessary a posteriori [Kripke] |
9174 | It is necessary that this table is not made of ice, but we don't know it a priori [Kripke] |
2408 | Kripke has demonstrated that some necessary truths are only knowable a posteriori [Kripke, by Chalmers] |
13967 | Kripke's essentialist necessary a posteriori opened the gap between conceivable and really possible [Soames on Kripke] |
13970 | Kripke gets to the necessary a posteriori by only allowing conceivability when combined with actuality [Kripke, by Soames] |
4943 | Instead of talking about possible worlds, we can always say "It is possible that.." [Kripke] |
4950 | Possible worlds are useful in set theory, but can be very misleading elsewhere [Kripke] |
16992 | Possible worlds aren't puzzling places to learn about, but places we ourselves describe [Kripke] |
16983 | Probability with dice uses possible worlds, abstractions which fictionally simplify things [Kripke] |
16993 | If we discuss what might have happened to Nixon, we stipulate that it is about Nixon [Kripke] |
16998 | Transworld identification is unproblematic, because we stipulate that we rigidly refer to something [Kripke] |
17001 | A table in some possible world should not even be identified by its essential properties [Kripke] |
4952 | Identification across possible worlds does not need properties, even essential ones [Kripke] |
13717 | Transworld identity is not a problem in de dicto sentences, which needn't identify an individual [Sider] |
7761 | Test for rigidity by inserting into the sentence 'N might not have been N' [Kripke, by Lycan] |
7693 | Kripke avoids difficulties of transworld identity by saying it is a decision, not a discovery [Kripke, by Jacquette] |
5821 | Saying that natural kinds are 'rigid designators' is the same as saying they are 'indexical' [Kripke, by Putnam] |
14068 | If Kripke names must still denote a thing in a non-actual situation, the statue isn't its clay [Gibbard on Kripke] |
10436 | A rigid expression may refer at a world to an object not existing in that world [Kripke, by Sainsbury] |
4953 | We do not begin with possible worlds and place objects in them; we begin with objects in the real world [Kripke] |
4961 | It is a necessary truth that Elizabeth II was the child of two particular parents [Kripke] |
9172 | A 'rigid designator' designates the same object in all possible worlds [Kripke] |
9173 | We cannot say that Nixon might have been a different man from the one he actually was [Kripke] |
17003 | Kaplan's 'Dthat' is a useful operator for transforming a description into a rigid designation [Kripke] |
9176 | Modal statements about this table never refer to counterparts; that confuses epistemology and metaphysics [Kripke] |
9221 | The best known objection to counterparts is Kripke's, that Humphrey doesn't care if his counterpart wins [Kripke, by Sider] |
14763 | Counterparts rest on similarity, so there are many such relations in different contexts [Sider] |
16986 | That there might have been unicorns is false; we don't know the circumstances for unicorns [Kripke] |
13719 | Barcan Formula problem: there might have been a ghost, despite nothing existing which could be a ghost [Sider] |
8259 | Kripke has breathed new life into the a priori/a posteriori distinction [Kripke, by Lowe] |
16989 | Rather than 'a priori truth', it is best to stick to whether some person knows it on a priori evidence [Kripke] |
4947 | A priori truths can be known independently of experience - but they don't have to be [Kripke] |
17052 | The a priori analytic truths involving fixing of reference are contingent [Kripke] |
13975 | Kripke was more successful in illuminating necessity than a priority (and their relations to analyticity) [Kripke, by Soames] |
17048 | Analytic judgements are a priori, even when their content is empirical [Kripke] |
4948 | Intuition is the strongest possible evidence one can have about anything [Kripke] |
4958 | Identities like 'heat is molecule motion' are necessary (in the highest degree), not contingent [Kripke] |
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] |
15011 | If the ultimate explanation is a list of entities, no laws, patterns or mechanisms can be cited [Sider] |
4969 | I regard the mind-body problem as wide open, and extremely confusing [Kripke] |
15018 | Intentionality is too superficial to appear in the catalogue of ultimate physics [Sider] |
4967 | It seems logically possible to have the pain brain state without the actual pain [Kripke] |
9177 | Identity theorists must deny that pains can be imagined without brain states [Kripke] |
7430 | Kripke assumes that mind-brain identity designates rigidly, which it doesn't [Armstrong on Kripke] |
7867 | If consciousness could separate from brain, then it cannot be identical with brain [Kripke, by Papineau] |
3228 | Kripke says pain is necessarily pain, but a brain state isn't necessarily painful [Kripke, by Rey] |
5832 | Identity must be necessary, but pain isn't necessarily a brain state, so they aren't identical [Kripke, by Schwartz,SP] |
4968 | Identity theorists seem committed to no-brain-event-no-pain, and vice versa, which seems wrong [Kripke] |
9178 | Pain, unlike heat, is picked out by an essential property [Kripke] |
19271 | No rule can be fully explained [Kripke] |
19269 | 'Quus' means the same as 'plus' if the ingredients are less than 57; otherwise it just produces 5 [Kripke] |
16383 | Puzzled Pierre has two mental files about the same object [Recanati on Kripke] |
14999 | Prior to conventions, not all green things were green? [Sider] |
7305 | Kripke's Wittgenstein says meaning 'vanishes into thin air' [Kripke, by Miller,A] |
19270 | If you ask what is in your mind for following the addition rule, meaning just seems to vanish [Kripke] |
17874 | Kripke has a definitional account of kinds, but not of naming [Almog on Kripke] |
16394 | Kripke derives accounts of reference and proper names from assumptions about worlds and essences [Stalnaker on Kripke] |
5822 | The important cause is not between dubbing and current use, but between the item and the speaker's information [Evans on Kripke] |
17033 | We may refer through a causal chain, but still change what is referred to [Kripke] |
4689 | Kripke makes reference a largely social matter, external to the mind of the speaker [Kripke, by McGinn] |
17504 | Kripke's theory is important because it gives a collective account of reference [Kripke, by Putnam] |
17035 | We refer through the community, going back to the original referent [Kripke] |
4956 | A description may fix a reference even when it is not true of its object [Kripke] |
16988 | Descriptive reference shows how to refer, how to identify two things, and how to challenge existence [Kripke, by PG] |
17029 | It can't be necessary that Aristotle had the properties commonly attributed to him [Kripke] |
17032 | Even if Gödel didn't produce his theorems, he's still called 'Gödel' [Kripke] |
11076 | Community implies assertability-conditions rather than truth-conditions semantics [Kripke, by Hanna] |
14893 | Rigid designation creates a puzzle - why do some necessary truths appear to be contingent? [Kripke, by Maciŕ/Garcia-Carpentiro] |
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] |
11075 | The sceptical rule-following paradox is the basis of the private language argument [Kripke, by Hanna] |
17056 | Terms for natural kinds are very close to proper names [Kripke] |
4963 | The properties that fix reference are contingent, the properties involving meaning are necessary [Kripke] |
17053 | Gold's atomic number might not be 79, but if it is, could non-79 stuff be gold? [Kripke] |
4964 | 'Cats are animals' has turned out to be a necessary truth [Kripke] |
6765 | Nominal essence may well be neither necessary nor sufficient for a natural kind [Kripke, by Bird] |
9387 | The scientific discovery (if correct) that gold has atomic number 79 is a necessary truth [Kripke] |
17054 | Scientific discoveries about gold are necessary truths [Kripke] |
17057 | Once we've found that heat is molecular motion, then that's what it is, in all possible worlds [Kripke] |
4965 | Science searches basic structures in search of essences [Kripke] |
14985 | The notion of law doesn't seem to enhance physical theories [Sider] |
14987 | Many of the key theories of modern physics do not appear to be 'laws' [Sider] |
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] |
14735 | Space is 3D and lacks a direction; time seems connected to causation [Sider] |
15021 | The central question in the philosophy of time is: How alike are time and space? [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] |
14736 | The B-theory is adequate, except that it omits to say which time is present [Sider] |
14734 | The B-series involves eternalism, and the reduction of tense [Sider] |
17050 | Tigers may lack all the properties we originally used to identify them [Kripke] |
17051 | The original concept of 'cat' comes from paradigmatic instances [Kripke] |
17049 | 'Tiger' designates a species, and merely looking like the species is not enough [Kripke] |