226 ideas
| 7396 | Hobbes created English-language philosophy [Hobbes, by Tuck] |
| 9218 | Maybe what distinguishes philosophy from science is its pursuit of necessary truths [Sider] |
| 17240 | Definitions are the first step in philosophy [Hobbes] |
| 6211 | Laughter is a sudden glory in realising the infirmity of others, or our own formerly [Hobbes] |
| 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] |
| 8014 | Resolve a complex into simple elements, then reconstruct the complex by using them [Hobbes, by MacIntyre] |
| 14986 | Conceptual analysts trust particular intuitions much more than general ones [Sider] |
| 17237 | Definitions of things that are caused must express their manner of generation [Hobbes] |
| 17239 | Definition is resolution of names into successive genera, and finally the difference [Hobbes] |
| 17241 | A defined name should not appear in the definition [Hobbes] |
| 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] |
| 17242 | 'Petitio principii' is reusing the idea to be defined, in disguised words [Hobbes] |
| 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] |
| 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] |
| 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] |
| 17245 | A part of a part is a part of a whole [Hobbes] |
| 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] |
| 13703 | λ can treat 'is cold and hungry' as a single predicate [Sider] |
| 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] |
| 17258 | If we just say one, one, one, one, we don't know where we have got to [Hobbes] |
| 13701 | A single second-order sentence validates all of arithmetic - but this can't be proved axiomatically [Sider] |
| 16789 | Only supernatural means could annihilate anything once it had being [Hobbes] |
| 17253 | Change is nothing but movement [Hobbes] |
| 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] |
| 7559 | Every part of the universe is body, and non-body is not part of it [Hobbes] |
| 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] |
| 16670 | Accidents are just modes of thinking about bodies [Hobbes] |
| 14995 | Predicates can be 'sparse' if there is a universal, or if there is a natural property or relation [Sider] |
| 16621 | Accidents are not parts of bodies (like blood in a cloth); they have accidents as things have a size [Hobbes] |
| 16734 | The complete power of an event is just the aggregate of the qualities that produced it [Hobbes] |
| 17247 | The only generalities or universals are names or signs [Hobbes] |
| 14960 | Bodies are independent of thought, and coincide with part of space [Hobbes] |
| 17250 | If you separate the two places of one thing, you will also separate the thing [Hobbes] |
| 17249 | If you separated two things in the same place, you would also separate the places [Hobbes] |
| 14745 | If sortal terms fix the kind and the persistence conditions, we need to know what kinds there are [Sider] |
| 17248 | If a whole body is moved, its parts must move with it [Hobbes] |
| 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] |
| 16620 | A chair is wood, and its shape is the form; it isn't 'compounded' of the matter and form [Hobbes] |
| 14747 | 'Composition as identity' says that an object just is the objects which compose it [Sider] |
| 16790 | A body is always the same, whether the parts are together or dispersed [Hobbes] |
| 17244 | To make a whole, parts needn't be put together, but can be united in the mind [Hobbes] |
| 17233 | Particulars contain universal things [Hobbes] |
| 17246 | Some accidental features are permanent, unless the object perishes [Hobbes] |
| 14757 | Mereological essentialism says an object's parts are necessary for its existence [Sider] |
| 17251 | The feature which picks out or names a thing is usually called its 'essence' [Hobbes] |
| 16622 | Essence is just an artificial word from logic, giving a way of thinking about substances [Hobbes] |
| 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] |
| 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] |
| 17257 | It is the same river if it has the same source, no matter what flows in it [Hobbes] |
| 12853 | Some individuate the ship by unity of matter, and others by unity of form [Hobbes] |
| 17256 | If a new ship were made of the discarded planks, would two ships be numerically the same? [Hobbes] |
| 14741 | The ship undergoes 'asymmetric' fission, where one candidate is seen as stronger [Sider] |
| 16794 | As an infant, Socrates was not the same body, but he was the same human being [Hobbes] |
| 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] |
| 17255 | Two bodies differ when (at some time) you can say something of one you can't say of the other [Hobbes] |
| 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] |
| 6215 | 'Contingent' means that the cause is unperceived, not that there is no cause [Hobbes] |
| 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] |
| 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] |
| 16582 | We can imagine a point swelling and contracting - but not how this could be done [Hobbes] |
| 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] |
| 16638 | The qualities of the world are mere appearances; reality is the motions which cause them [Hobbes] |
| 2356 | Appearance and reality can be separated by mirrors and echoes [Hobbes] |
| 16688 | Evidence is conception, which is imagination, which proceeds from the senses [Hobbes] |
| 7405 | Experience can't prove universal truths [Hobbes] |
| 3061 | Anaxarchus said that he was not even sure that he knew nothing [Anaxarchus, by Diog. Laertius] |
| 2357 | Dreams must be false because they seem absurd, but dreams don't see waking as absurd [Hobbes] |
| 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] |
| 17238 | Science aims to show causes and generation of things [Hobbes] |
| 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] |
| 17260 | Imagination is just weakened sensation [Hobbes] |
| 19373 | A 'conatus' is an initial motion, experienced by us as desire or aversion [Hobbes, by Arthur,R] |
| 2385 | If a man suddenly develops an intention of doing something, the cause is out of his control, not in his will [Hobbes] |
| 2358 | Freedom is absence of opposition to action; the idea of 'free will' is absurd [Hobbes] |
| 2384 | Those actions that follow immediately the last appetite are voluntary [Hobbes] |
| 6213 | A man cannot will to will, or will to will to will, so the idea of a voluntary will is absurd [Hobbes] |
| 6214 | Liberty and necessity are consistent, as when water freely flows, by necessity [Hobbes] |
| 6208 | Conceptions and apparitions are just motion in some internal substance of the head [Hobbes] |
| 2948 | Sensation is merely internal motion of the sentient being [Hobbes] |
| 23987 | The 'simple passions' are appetite, desire, love, aversion, hate, joy, and grief [Hobbes, by Goldie] |
| 17261 | Apart from pleasure and pain, the only emotions are appetite and aversion [Hobbes] |
| 17236 | Words are not for communication, but as marks for remembering what we have learned [Hobbes] |
| 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] |
| 2362 | The will is just the last appetite before action [Hobbes] |
| 7408 | It is an error that reason should control the passions, which give right guidance on their own [Hobbes, by Tuck] |
| 2363 | Reason is usually general, but deliberation is of particulars [Hobbes] |
| 7407 | Good and evil are what please us; goodness and badness the powers causing them [Hobbes] |
| 2360 | 'Good' is just what we desire, and 'Evil' what we hate [Hobbes] |
| 7410 | Self-preservation is basic, and people judge differently about that, implying ethical relativism [Hobbes, by Tuck] |
| 2368 | Men's natural desires are no sin, and neither are their actions, until law makes it so [Hobbes] |
| 6209 | There is no absolute good, for even the goodness of God is goodness to us [Hobbes] |
| 2359 | Desire and love are the same, but in the desire the object is absent, and in love it is present [Hobbes] |
| 2370 | All voluntary acts aim at some good for the doer [Hobbes] |
| 7409 | Hobbes shifted from talk of 'the good' to talk of 'rights' [Hobbes, by Tuck] |
| 6210 | Life has no end (not even happiness), because we have desires, which presuppose a further end [Hobbes] |
| 2371 | A contract is a mutual transfer of rights [Hobbes] |
| 2372 | The person who performs first in a contract is said to 'merit' the return, and is owed it [Hobbes] |
| 8015 | Hobbes wants a contract to found morality, but shared values are needed to make a contract [MacIntyre on Hobbes] |
| 5337 | For Hobbes the Golden Rule concerns not doing things, whereas Jesus encourages active love [Hobbes, by Flanagan] |
| 2374 | In the violent state of nature, the merest suspicion is enough to justify breaking a contract [Hobbes] |
| 2375 | Suspicion will not destroy a contract, if there is a common power to enforce it [Hobbes] |
| 8016 | Fear of sanctions is the only motive for acceptance of authority that Hobbes can think of [MacIntyre on Hobbes] |
| 2377 | No one who admitted to not keeping contracts could ever be accepted as a citizen [Hobbes] |
| 2379 | If there is a good reason for breaking a contract, the same reason should have stopped the making of it [Hobbes] |
| 2373 | The first performer in a contract is handing himself over to an enemy [Hobbes] |
| 2382 | Someone who keeps all his contracts when others are breaking them is making himself a prey to others [Hobbes] |
| 2383 | Virtues are a means to peaceful, sociable and comfortable living [Hobbes] |
| 2376 | Injustice is the failure to keep a contract, and justice is the constant will to give what is owed [Hobbes] |
| 2367 | In time of war the life of man is solitary, poor, nasty, brutish and short [Hobbes] |
| 19764 | Hobbes attributed to savages the passions which arise in a law-bound society [Hobbes, by Rousseau] |
| 20566 | Hobbes says the people voluntarily give up their sovereignty, in a contract with a ruler [Hobbes, by Oksala] |
| 2366 | There is not enough difference between people for one to claim more benefit than another [Hobbes] |
| 20485 | Hobbes says people are roughly equal; Locke says there is no right to impose inequality [Hobbes, by Wolff,J] |
| 2369 | If we seek peace and defend ourselves, we must compromise on our rights [Hobbes] |
| 20484 | We should obey the laws of nature, provided other people are also obeying them [Hobbes, by Wolff,J] |
| 7573 | The legal positivism of Hobbes said law is just formal or procedural [Hobbes, by Jolley] |
| 2380 | Punishment should only be for reform or deterrence [Hobbes] |
| 23609 | I act justly if I follow my Prince in an apparently unjust war, and refusing to fight would be injustice [Hobbes] |
| 2361 | If fear of unknown powers is legal it is religion, if it is illegal it is superstition [Hobbes] |
| 6212 | Lust involves pleasure, and also the sense of power in pleasing others [Hobbes] |
| 16600 | Prime matter is body considered with mere size and extension, and potential [Hobbes] |
| 17252 | Acting on a body is either creating or destroying a property in it [Hobbes] |
| 17254 | An effect needs a sufficient and necessary cause [Hobbes] |
| 2364 | Causation is only observation of similar events following each other, with nothing visible in between [Hobbes] |
| 17235 | A cause is the complete sum of the features which necessitate the effect [Hobbes] |
| 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] |
| 17234 | Motion is losing one place and acquiring another [Hobbes] |
| 14725 | Maybe motion is a dynamical quantity intrinsic to a thing at a particular time [Sider] |
| 17259 | 'Force' is the quantity of movement imposed on something [Hobbes] |
| 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] |
| 17243 | Past times can't exist anywhere, apart from in our memories [Hobbes] |
| 7411 | The attributes of God just show our inability to conceive his nature [Hobbes] |
| 2365 | Religion is built on ignorance and misinterpretation of what is unknown or frightening [Hobbes] |
| 2378 | Belief in an afterlife is based on poorly founded gossip [Hobbes] |