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Single Idea 14981

[filed under theme 2. Reason / D. Definition / 13. Against Definition ]

Full Idea

Philosophical concepts of interest are rarely reductively defined; still more rarely does our understanding of such concepts rest on definitions. ...(We generally understand concepts to the extent that we know what role they play in thinking).

Gist of Idea

Philosophical concepts are rarely defined, and are not understood by means of definitions

Source

Theodore Sider (Writing the Book of the World [2011], 02.1)

Book Ref

Sider,Theodore: 'Writing the Book of the World' [OUP 2011], p.9

A Reaction

I'm not sure that I agree with this. I suspect that Sider has the notion of definition in mind that is influenced by lexicography. Aristotle's concept of definition I take to be lengthy and expansive, and that is very relevant to philosophy.

The 124 ideas from Theodore Sider

14752 Artists 'create' statues because they are essentially statues, and so lack identity with the lump of clay [Sider]
14721 Metaphysical enquiry can survive if its conclusions are tentative [Sider]
14722 Between presentism and eternalism is the 'growing block' view - the past is real, the future is not [Sider]
14723 Talk using tenses can be eliminated, by reducing it to indexical connections for an utterance [Sider]
14725 Maybe motion is a dynamical quantity intrinsic to a thing at a particular time [Sider]
14724 Presentists must deny truths about multiple times [Sider]
14194 Proper ontology should only use categorical (actual) properties, not hypothetical ones [Sider]
14727 Three-dimensionalists assert 'enduring', being wholly present at each moment, and deny 'temporal parts' [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]
14734 The B-series involves eternalism, and the reduction of tense [Sider]
14735 Space is 3D and lacks a direction; time seems connected to causation [Sider]
14736 The B-theory is adequate, except that it omits to say which time is present [Sider]
14740 If Tib is all of Tibbles bar her tail, when Tibbles loses her tail, two different things become one [Sider]
14741 The ship undergoes 'asymmetric' fission, where one candidate is seen as stronger [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]
14745 If sortal terms fix the kind and the persistence conditions, we need to know what kinds there are [Sider]
14754 If you say Leibniz's Law doesn't apply to 'timebound' properties, you are no longer discussing identity [Sider]
14756 For Presentists there must always be a temporal vantage point for any description [Sider]
14757 Mereological essentialism says an object's parts are necessary for its existence [Sider]
14758 How can an instantaneous stage believe anything, if beliefs take time? [Sider]
14760 Four-dimensionalism sees things and processes as belonging in the same category [Sider]
14762 Four-dimensionalism says temporal parts are caused (through laws of motion) by previous temporal parts [Sider]
14763 Counterparts rest on similarity, so there are many such relations in different contexts [Sider]
14738 Some might say that its inconsistency with time travel is a reason to favour three-dimensionalism [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]
13683 A relation is a feature of multiple objects taken together [Sider]
13724 In model theory, first define truth, then validity as truth in all models, and consequence as truth-preservation [Sider]
13684 The semantical notion of a logical truth is validity, being true in all interpretations [Sider]
13685 Natural deduction helpfully allows reasoning with assumptions [Sider]
13686 We can build proofs just from conclusions, rather than from plain formulae [Sider]
13687 No assumptions in axiomatic proofs, so no conditional proof or reductio [Sider]
13688 Good axioms should be indisputable logical truths [Sider]
13689 'Theorems' are formulas provable from no premises at all [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]
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]
13697 Valuations in PC assign truth values to formulas relative to variable assignments [Sider]
13696 When a variable is 'free' of the quantifier, the result seems incapable of truth or falsity [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]
13700 A 'total' function must always produce an output for a given domain [Sider]
13701 A single second-order sentence validates all of arithmetic - but this can't be proved axiomatically [Sider]
13702 The identity of indiscernibles is necessarily true, if being a member of some set counts as a property [Sider]
13703 λ can treat 'is cold and hungry' as a single predicate [Sider]
13705 Truth tables assume truth functionality, and are just pictures of truth functions [Sider]
13704 It is hard to say which are the logical truths in modal logic, especially for iterated modal operators [Sider]
13706 Intuitively, deontic accessibility seems not to be reflexive, but to be serial [Sider]
13707 Maybe metaphysical accessibility is intransitive, if a world in which I am a frog is impossible [Sider]
13708 S5 is the strongest system, since it has the most valid formulas, because it is easy to be S5-valid [Sider]
13709 Logical truths must be necessary if anything is [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]
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]
13715 You can employ intuitionist logic without intuitionism about mathematics [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]
13717 Transworld identity is not a problem in de dicto sentences, which needn't identify an individual [Sider]
13719 Barcan Formula problem: there might have been a ghost, despite nothing existing which could be a ghost [Sider]
13720 Converse Barcan Formula: □∀αφ→∀α□φ [Sider]
13718 The Barcan Formula ∀x□Fx→□∀xFx may be a defect in modal logic [Sider]
13721 'Strong' necessity in all possible worlds; 'weak' necessity in the worlds where the relevant objects exist [Sider]
13723 System B is needed to prove the Barcan Formula [Sider]
13722 A 'theorem' is an axiom, or the last line of a legitimate proof [Sider]
9218 Maybe what distinguishes philosophy from science is its pursuit of necessary truths [Sider]
14977 Metaphysics is not about what exists or is true or essential; it is about the structure of reality [Sider]
14978 A property is intrinsic if an object alone in the world can instantiate it [Sider]
14980 There is a real issue over what is the 'correct' logic [Sider]
14981 Philosophical concepts are rarely defined, and are not understood by means of definitions [Sider]
14982 If I used Ramsey sentences to eliminate fundamentality from my theory, that would be a real loss [Sider]
14984 Which should be primitive in mereology - part, or overlap? [Sider]
14983 Accept the ontology of your best theory - and also that it carves nature at the joints [Sider]
14985 The notion of law doesn't seem to enhance physical theories [Sider]
14986 Conceptual analysts trust particular intuitions much more than general ones [Sider]
14987 Many of the key theories of modern physics do not appear to be 'laws' [Sider]
14988 A theory which doesn't fit nature is unexplanatory, even if it is true [Sider]
14990 Bayes produces weird results if the prior probabilities are bizarre [Sider]
14989 Problem predicates in induction don't reflect the structure of nature [Sider]
14991 Space has real betweenness and congruence structure (though it is not the Euclidean concepts) [Sider]
14992 We don't care about plain truth, but truth in joint-carving terms [Sider]
14994 Extreme doubts about metaphysics also threaten to undermine the science of unobservables [Sider]
14995 Predicates can be 'sparse' if there is a universal, or if there is a natural property or relation [Sider]
14997 Two applications of 'grue' do not guarantee a similarity between two things [Sider]
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]
15001 'Tonk' is supposed to follow the elimination and introduction rules, but it can't be so interpreted [Sider]
15000 'It is raining' and 'it is not raining' can't be legislated, so we can't legislate 'p or ¬p' [Sider]
15004 'Gunk' is an object in which proper parts all endlessly have further proper parts [Sider]
15005 Explanations must cite generalisations [Sider]
15003 It seems unlikely that the way we speak will give insights into the universe [Sider]
15008 Is fundamentality in whole propositions (and holistic), or in concepts (and atomic)? [Sider]
15009 We must distinguish 'concrete' from 'abstract' and necessary states of affairs. [Sider]
15010 Your metaphysics is 'cheating' if your ontology won't support the beliefs you accept [Sider]
15012 Orthodox truthmaker theories make entities fundamental, but that is poor for explanation [Sider]
15011 If the ultimate explanation is a list of entities, no laws, patterns or mechanisms can be cited [Sider]
15013 Tables and chairs have fundamental existence, but not fundamental natures [Sider]
15017 Supervenience is a modal connection [Sider]
15014 Unlike things, stuff obeys unrestricted composition and mereological essentialism [Sider]
15015 It seems possible for a correct definition to be factually incorrect, as in defining 'contact' [Sider]
15016 Analyticity has lost its traditional role, which relied on truth by convention [Sider]
15019 Define logical constants by role in proofs, or as fixed in meaning, or as topic-neutral [Sider]
15020 Classical logic is good for mathematics and science, but less good for natural language [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]
15023 The Barcan schema implies if X might have fathered something, there is something X might have fathered [Sider]
15025 The world does not contain necessity and possibility - merely how things are [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]
15026 Essence (even if nonmodal) is not fundamental in metaphysics [Sider]
15033 Humeans says mathematics and logic are necessary because that is how our concept of necessity works [Sider]
15030 Humeans say that we decide what is necessary [Sider]
15029 Modal accounts of logical consequence are simple necessity, or essential use of logical words [Sider]
15031 Modal terms in English are entirely contextual, with no modality outside the language [Sider]
15018 Intentionality is too superficial to appear in the catalogue of ultimate physics [Sider]