92 ideas
| 13734 | Modern Quinean metaphysics is about what exists, but Aristotelian metaphysics asks about grounding [Schaffer,J] |
| Full Idea: On the now dominant Quinean view, metaphysics is about what there is (such as properties, meanings and numbers). I will argue for the revival of a more traditional Aristotelian view, on which metaphysics is about what grounds what. | |
| From: Jonathan Schaffer (On What Grounds What [2009], Intro) | |
| A reaction: I find that an enormously helpful distinction, and support the Aristotelian view. Schaffer's general line is that what exists is fairly uncontroversial and dull, but the interesting truths about the world emerge when we grasp its structure. |
| 13751 | If you tore the metaphysics out of philosophy, the whole enterprise would collapse [Schaffer,J] |
| Full Idea: Traditional metaphysics is so tightly woven into the fabric of philosophy that it cannot be torn out without the whole tapestry unravelling. | |
| From: Jonathan Schaffer (On What Grounds What [2009], 2.3) | |
| A reaction: I often wonder why the opponents of metaphysics still continue to do philosophy. I don't see how you address questions of ethics, or philosophy of mathematics (etc) without coming up against highly general and abstract over-questions. |
| 3807 | Reason is and ought to be the slave of the passions [Hume] |
| Full Idea: Reason is and ought to be the slave of the passions, and can never pretend to any other office than to serve and obey them. | |
| From: David Hume (Treatise of Human Nature [1739], II.III.3) |
| 13743 | We should not multiply basic entities, but we can have as many derivative entities as we like [Schaffer,J] |
| Full Idea: Occam's Razor should only be understood to concern substances: do not multiply basic entities without necessity. There is no problem with the multiplication of derivative entities - they are an 'ontological free lunch'. | |
| From: Jonathan Schaffer (On What Grounds What [2009], 2.1) | |
| A reaction: The phrase 'ontological free lunch' comes from Armstrong. This is probably what Occam meant. A few extra specks of dust, or even a few more numbers (thank you, Cantor!) don't seem to challenge the principle. |
| 10859 | A set is 'well-ordered' if every subset has a first element [Clegg] |
| Full Idea: For a set to be 'well-ordered' it is required that every subset of the set has a first element. | |
| From: Brian Clegg (Infinity: Quest to Think the Unthinkable [2003], Ch.13) |
| 10857 | Set theory made a closer study of infinity possible [Clegg] |
| Full Idea: Set theory made a closer study of infinity possible. | |
| From: Brian Clegg (Infinity: Quest to Think the Unthinkable [2003], Ch.13) |
| 10864 | Any set can always generate a larger set - its powerset, of subsets [Clegg] |
| Full Idea: The idea of the 'power set' means that it is always possible to generate a bigger one using only the elements of that set, namely the set of all its subsets. | |
| From: Brian Clegg (Infinity: Quest to Think the Unthinkable [2003], Ch.14) |
| 10872 | Extensionality: Two sets are equal if and only if they have the same elements [Clegg] |
| Full Idea: Axiom of Extension: Two sets are equal if and only if they have the same elements. | |
| From: Brian Clegg (Infinity: Quest to Think the Unthinkable [2003], Ch.15) |
| 10875 | Pairing: For any two sets there exists a set to which they both belong [Clegg] |
| Full Idea: Axiom of Pairing: For any two sets there exists a set to which they both belong. So you can make a set out of two other sets. | |
| From: Brian Clegg (Infinity: Quest to Think the Unthinkable [2003], Ch.15) |
| 10876 | Unions: There is a set of all the elements which belong to at least one set in a collection [Clegg] |
| Full Idea: Axiom of Unions: For every collection of sets there exists a set that contains all the elements that belong to at least one of the sets in the collection. | |
| From: Brian Clegg (Infinity: Quest to Think the Unthinkable [2003], Ch.15) |
| 10878 | Infinity: There exists a set of the empty set and the successor of each element [Clegg] |
| Full Idea: Axiom of Infinity: There exists a set containing the empty set and the successor of each of its elements. | |
| From: Brian Clegg (Infinity: Quest to Think the Unthinkable [2003], Ch.15) | |
| A reaction: This is rather different from the other axioms because it contains the notion of 'successor', though that can be generated by an ordering procedure. |
| 10877 | Powers: All the subsets of a given set form their own new powerset [Clegg] |
| Full Idea: Axiom of Powers: For each set there exists a collection of sets that contains amongst its elements all the subsets of the given set. | |
| From: Brian Clegg (Infinity: Quest to Think the Unthinkable [2003], Ch.15) | |
| A reaction: Obviously this must include the whole of the base set (i.e. not just 'proper' subsets), otherwise the new set would just be a duplicate of the base set. |
| 10879 | Choice: For every set a mechanism will choose one member of any non-empty subset [Clegg] |
| Full Idea: Axiom of Choice: For every set we can provide a mechanism for choosing one member of any non-empty subset of the set. | |
| From: Brian Clegg (Infinity: Quest to Think the Unthinkable [2003], Ch.15) | |
| A reaction: This axiom is unusual because it makes the bold claim that such a 'mechanism' can always be found. Cohen showed that this axiom is separate. The tricky bit is choosing from an infinite subset. |
| 10871 | Axiom of Existence: there exists at least one set [Clegg] |
| Full Idea: Axiom of Existence: there exists at least one set. This may be the empty set, but you need to start with something. | |
| From: Brian Clegg (Infinity: Quest to Think the Unthinkable [2003], Ch.15) |
| 10874 | Specification: a condition applied to a set will always produce a new set [Clegg] |
| Full Idea: Axiom of Specification: For every set and every condition, there corresponds a set whose elements are exactly the same as those elements of the original set for which the condition is true. So the concept 'number is even' produces a set from the integers. | |
| From: Brian Clegg (Infinity: Quest to Think the Unthinkable [2003], Ch.15) | |
| A reaction: What if the condition won't apply to the set? 'Number is even' presumably won't produce a set if it is applied to a set of non-numbers. |
| 10880 | Mathematics can be 'pure' (unapplied), 'real' (physically grounded); or 'applied' (just applicable) [Clegg] |
| Full Idea: Three views of mathematics: 'pure' mathematics, where it doesn't matter if it could ever have any application; 'real' mathematics, where every concept must be physically grounded; and 'applied' mathematics, using the non-real if the results are real. | |
| From: Brian Clegg (Infinity: Quest to Think the Unthinkable [2003], Ch.17) | |
| A reaction: Very helpful. No one can deny the activities of 'pure' mathematics, but I think it is undeniable that the origins of the subject are 'real' (rather than platonic). We do economics by pretending there are concepts like the 'average family'. |
| 10860 | An ordinal number is defined by the set that comes before it [Clegg] |
| Full Idea: You can think of an ordinal number as being defined by the set that comes before it, so, in the non-negative integers, ordinal 5 is defined as {0, 1, 2, 3, 4}. | |
| From: Brian Clegg (Infinity: Quest to Think the Unthinkable [2003], Ch.13) |
| 10861 | Beyond infinity cardinals and ordinals can come apart [Clegg] |
| Full Idea: With ordinary finite numbers ordinals and cardinals are in effect the same, but beyond infinity it is possible for two sets to have the same cardinality but different ordinals. | |
| From: Brian Clegg (Infinity: Quest to Think the Unthinkable [2003], Ch.13) |
| 10854 | Transcendental numbers can't be fitted to finite equations [Clegg] |
| Full Idea: The 'transcendental numbers' are those irrationals that can't be fitted to a suitable finite equation, of which π is far and away the best known. | |
| From: Brian Clegg (Infinity: Quest to Think the Unthinkable [2003], Ch. 6) |
| 10858 | By adding an axis of imaginary numbers, we get the useful 'number plane' instead of number line [Clegg] |
| Full Idea: The realisation that brought 'i' into the toolkit of physicists and engineers was that you could extend the 'number line' into a new dimension, with an imaginary number axis at right angles to it. ...We now have a 'number plane'. | |
| From: Brian Clegg (Infinity: Quest to Think the Unthinkable [2003], Ch.12) |
| 10853 | Either lack of zero made early mathematics geometrical, or the geometrical approach made zero meaningless [Clegg] |
| Full Idea: It is a chicken-and-egg problem, whether the lack of zero forced forced classical mathematicians to rely mostly on a geometric approach to mathematics, or the geometric approach made 0 a meaningless concept, but the two remain strongly tied together. | |
| From: Brian Clegg (Infinity: Quest to Think the Unthinkable [2003], Ch. 6) |
| 10866 | Cantor's account of infinities has the shaky foundation of irrational numbers [Clegg] |
| Full Idea: As far as Kronecker was concerned, Cantor had built a whole structure on the irrational numbers, and so that structure had no foundation at all. | |
| From: Brian Clegg (Infinity: Quest to Think the Unthinkable [2003], Ch.15) |
| 10869 | The Continuum Hypothesis is independent of the axioms of set theory [Clegg] |
| Full Idea: Paul Cohen showed that the Continuum Hypothesis is independent of the axioms of set theory. | |
| From: Brian Clegg (Infinity: Quest to Think the Unthinkable [2003], Ch.15) |
| 10862 | The 'continuum hypothesis' says aleph-one is the cardinality of the reals [Clegg] |
| Full Idea: The 'continuum hypothesis' says that aleph-one is the cardinality of the rational and irrational numbers. | |
| From: Brian Clegg (Infinity: Quest to Think the Unthinkable [2003], Ch.14) |
| 8649 | Two numbers are equal if all of their units correspond to one another [Hume] |
| Full Idea: When two numbers are so combin'd, as that the one has always a unit answering to every unit of the other, we pronounce them equal. | |
| From: David Hume (Treatise of Human Nature [1739], I.III.1) | |
| A reaction: This became known as Hume's Principle after Frege made use of it for logicism (Foundations §63). It reduces equality to something fairly simple and visual (one-to-one correspondence). But we also say that two logicians or musicians are 'equal' in ability. |
| 13741 | If 'there are red roses' implies 'there are roses', then 'there are prime numbers' implies 'there are numbers' [Schaffer,J] |
| Full Idea: We can automatically infer 'there are roses' from 'there are red roses' (with no shift in the meaning of 'roses'). Likewise one can automatically infer 'there are numbers' from 'there are prime numbers'. | |
| From: Jonathan Schaffer (On What Grounds What [2009], 2.1) | |
| A reaction: He similarly observes that the atheist's 'God is a fictional character' implies 'there are fictional characters'. Schaffer is not committing to a strong platonism with his claim - merely that the existence of numbers is hardly worth disputing. |
| 21291 | There is no medium state between existence and non-existence [Hume] |
| Full Idea: Betwixt unity and number there can be no medium; no more than betwixt existence and non-existence. | |
| From: David Hume (Treatise of Human Nature [1739], I.IV.2) | |
| A reaction: Just to confirm that, as you would expect, the great empiricist has no time for 'subsistence', or shadows and holes having lower grade existece. |
| 13748 | Grounding is unanalysable and primitive, and is the basic structuring concept in metaphysics [Schaffer,J] |
| Full Idea: Grounding should be taken as primitive, as per the neo-Aristotelian approach. Grounding is an unanalyzable but needed notion - it is the primitive structuring conception of metaphysics. | |
| From: Jonathan Schaffer (On What Grounds What [2009], 2.2) | |
| A reaction: [he cites K.Fine 1991] I find that this simple claim clarifies the discussions of Kit Fine, where you are not always quite sure what the game is. I agree fully with it. It makes metaphysics interesting, where cataloguing entities is boring. |
| 13747 | Supervenience is just modal correlation [Schaffer,J] |
| Full Idea: Supervenience is mere modal correlation. | |
| From: Jonathan Schaffer (On What Grounds What [2009], 2.2) |
| 13744 | The cosmos is the only fundamental entity, from which all else exists by abstraction [Schaffer,J] |
| Full Idea: My preferred view is that there is only one fundamental entity - the whole concrete cosmos - from which all else exists by abstraction. | |
| From: Jonathan Schaffer (On What Grounds What [2009], 2.1) | |
| A reaction: This looks to me like weak anti-realism - that there are no natural 'joints' in nature - but I don't think Schaffer intends that. I take the joints to be fundamentals, which necessitates that the cosmos has parts. His 'abstraction' is clearly a process. |
| 13739 | Maybe categories are just the different ways that things depend on basic substances [Schaffer,J] |
| Full Idea: Maybe the categories are determined by the different grounding relations, ..so that categories just are the ways things depend on substances. ...Categories are places in the dependence ordering. | |
| From: Jonathan Schaffer (On What Grounds What [2009], 1.3) |
| 11942 | Power is the possibility of action, as discovered by experience [Hume] |
| Full Idea: Power consists in the possibility or probability of any action, as discovered by experience and the practice of the world. | |
| From: David Hume (Treatise of Human Nature [1739], p.313), quoted by George Molnar - Powers 5 | |
| A reaction: [page in OUP edn] This strikes me as blatantly false, and typical of those who confuse epistemology with ontology. It implies that a power that takes everyone by surprise is impossible, by definition. |
| 11949 | There may well be powers in things, with which we are quite unacquainted [Hume] |
| Full Idea: I am, indeed, ready to allow, that there may be several qualities both in material and immaterial objects, with which we are utterly unacquainted; and if we please to call these powers and efficiency, 'twill be be of little consequence to the world. | |
| From: David Hume (Treatise of Human Nature [1739], p.168), quoted by George Molnar - Powers 7.2.1 | |
| A reaction: A delightful air of casual indifference. What the classic empiricists needed was a notion of 'best explanation', which would allow them to leap beyond immediate experience. They made plenty of other leaps beyond experience, though Hume hated them. |
| 11950 | We have no idea of powers, because we have no impressions of them [Hume] |
| Full Idea: We never have any impression that contains any power or efficacy. We never therefore have any idea of power. | |
| From: David Hume (Treatise of Human Nature [1739], p.161), quoted by George Molnar - Powers 7.2.1 | |
| A reaction: [page in Selby-Bigges edn] It seems to me plausible that Hume is utterly wrong, because our own mental lives are a direct and constant experience of the physical powers and efficacies of material objects. |
| 11941 | The distinction between a power and its exercise is entirely frivolous [Hume] |
| Full Idea: The distinction which we sometimes make betwixt a power and the exercise of it is entirely frivolous, and ... neither man nor any other being ought ever to be thought possesst of any ability, unless it be exerted and put into action. | |
| From: David Hume (Treatise of Human Nature [1739], p.311), quoted by George Molnar - Powers 5 | |
| A reaction: [page in OUP] Molnar says this strong intuition is shared by most of us, but I take the world to be full of people who can play the piano or speak Spanish, but never actually do it. [but see Idea 11942] Most wasps never sting anything. |
| 11098 | Momentary impressions are wrongly identified with one another on the basis of resemblance [Hume, by Quine] |
| Full Idea: Momentary impressions, according to Hume, are wrongly identified with one another on the basis of resemblance. | |
| From: report of David Hume (Treatise of Human Nature [1739]) by Willard Quine - Identity, Ostension, and Hypostasis 3 | |
| A reaction: I don't have a Hume quotation for this yet, but Quine is plausibly claiming Hume as a resemblance nominalist, equipped with an error theory about universals. |
| 7954 | If we see a resemblance among objects, we apply the same name to them, despite their differences [Hume] |
| Full Idea: When we have found a resemblance among several objects, that often occur to us, we apply the same name to all of them, whatever differences we may observe in the degrees of their quantity and quality, and whatever other differences may appear among them. | |
| From: David Hume (Treatise of Human Nature [1739], I.I.7) | |
| A reaction: This must to some extent by right, whatever objections can be found. Russell's objection (Idea 4441) wouldn't alter the truth of Hume's observation, thought Hume is attacking universals and Russell defending them. |
| 21293 | Individuation is only seeing that a thing is stable and continuous over time [Hume] |
| Full Idea: The principle of individuation is nothing but the invariableness and uninterruptedness of any object through a supposed variation of time, by which the mind can trace it in the different periods of its existence. | |
| From: David Hume (Treatise of Human Nature [1739], I.IV.2) | |
| A reaction: Not convinced by this. I can individuate something by an almost instantaneous glimpse. I don't increasingly individuate it as time passes. Instant viewing of type and structure may be enough. |
| 12048 | The only meaning we have for substance is a collection of qualities [Hume] |
| Full Idea: We have no idea of substance, distinct from that of a collection of particular qualities, nor have we any other meaning when we either talk or reason concerning it. | |
| From: David Hume (Treatise of Human Nature [1739], I.I.6) | |
| A reaction: This is the standard empiricist view of such things, firmly stated. It is tempting to say that Hume has simply misunderstood the word, since it is precisely intended to mean not the qualities, but what underlies them, and persists. |
| 13424 | Aristotelians propose accidents supported by substance, but they don't understand either of them [Hume] |
| Full Idea: The peripatetic philosophers carry their fictions still further, and both suppose a substance supporting, which they do not understand, and an accident supported, of which they have as imperfect an idea. The whole system is entirely incomprehensible. | |
| From: David Hume (Treatise of Human Nature [1739], I.IV.3) | |
| A reaction: It seems to me that if you put it to Aristotle that he didn't understand 'substantial form', he would concede the point, but nevertheless say that it was ideal at which knowledge aimed. Locke is much more astute than Hume on this. |
| 13742 | There exist heaps with no integral unity, so we should accept arbitrary composites in the same way [Schaffer,J] |
| Full Idea: I am happy to accept universal composition, on the grounds that there are heaps, piles etc with no integral unity, and that arbitrary composites are no less unified than heaps. | |
| From: Jonathan Schaffer (On What Grounds What [2009], 2.1 n11) | |
| A reaction: The metaphysical focus is then placed on what constitutes 'integral unity', which is precisely the question which most interested Aristotle. Clearly if there is nothing more to an entity than its components, scattering them isn't destruction. |
| 13752 | The notion of 'grounding' can explain integrated wholes in a way that mere aggregates can't [Schaffer,J] |
| Full Idea: The notion of grounding my capture a crucial mereological distinction (missing from classical mereology) between an integrated whole with genuine unity, and a mere aggregate. x is an integrated whole if it grounds its proper parts. | |
| From: Jonathan Schaffer (On What Grounds What [2009], 3.1) | |
| A reaction: That gives a nice theoretical notion, but if you remove each of the proper parts, does x remain? Is it a bare particular? I take it that it will have to be an abstract principle, the one Aristotle was aiming at with his notion of 'form'. Schaffer agrees. |
| 21299 | Changing a part can change the whole, not absolutely, but by its proportion of the whole [Hume] |
| Full Idea: Though the change of any considerable part of a mass of matter destroys the identity of the whole, yet we must measure the greatness of the part, not absolutely, but by its proportion to the whole. | |
| From: David Hume (Treatise of Human Nature [1739], I.IV.6) | |
| A reaction: This seems to nicely demonstrate that the wholeness is in the mind of the perceiver, and does not simply depend on objective facts. Compare the proportion needed to change my pile of mud and my pile of gold. |
| 21300 | A change more obviously destroys an identity if it is quick and observed [Hume] |
| Full Idea: A change in any considerable part of a body destroys its identity; but 'tis remarkable that where the change is produced gradually and insensibly we are less apt to ascribe to it the same effect. | |
| From: David Hume (Treatise of Human Nature [1739], I.IV.6) | |
| A reaction: Broad spotted that landscapes change too, but so slowly that we barely admit any change at all. The type of change also matters. If my car slowly changes to chocolate the speed of change is a minor factor. |
| 1321 | If identity survives change or interruption, then resemblance, contiguity or causation must unite the parts of it [Hume] |
| Full Idea: The objects which are variable or interrupted, and yet are supposed to continue the same, are such only as consist of a succession of parts, connected together by resemblance, contiguity, or causation. | |
| From: David Hume (Treatise of Human Nature [1739], I.IV.6) |
| 1330 | If a republic can retain identity through many changes, so can an individual [Hume] |
| Full Idea: As the same individual republic may not only change its members, but also its laws and constitutions; in like manner the same person may vary his character and disposition, as well as his impressions and ideas, without losing his identity. | |
| From: David Hume (Treatise of Human Nature [1739], I.IV.6) |
| 21302 | If a ruined church is rebuilt, its relation to its parish makes it the same church [Hume] |
| Full Idea: If a church which was formerly of brick fell to ruin, the parish can build the same church of free-stone, with modern architecture. Neither the form nor materials are the same, but their relation to the parishioners is sufficient to say they are the same. | |
| From: David Hume (Treatise of Human Nature [1739], I.IV.6) | |
| A reaction: The clearly invites the question of whether this is type-identity or token-identity. If the parish decided they wanted two churches they obviously wouldn't be the same (even if they then demolished the first one). |
| 21303 | We accept the identity of a river through change, because it is the river's nature [Hume] |
| Full Idea: Where the objects are in their nature changeable and inconstant, we admit of a more sudden transition. The nature of a river consists in the motion and change of parts. What is expected appears of less moment than what is unusual and extraordinary. | |
| From: David Hume (Treatise of Human Nature [1739], I.IV.6) | |
| A reaction: Aha! Little does Hume realise how Aristotelian he is! Aristotle may have a more objective view of the 'nature' of a thing, but making inferences about identity over time from a thing's essential nature is pure Aristotle. |
| 21301 | The purpose of the ship makes it the same one through all variations [Hume] |
| Full Idea: The common end [of a ship], in which the parts conspire, is the same under all variations, and affords an easy transition of the imagination from one situation of the body to another. | |
| From: David Hume (Treatise of Human Nature [1739], I.IV.6) | |
| A reaction: It is not true that a ship remains the same under ALL variations. Consider gradually changing a yacht into a racing powerboat. You might say the purpose is then changed, but the slight variations in a yacht can slightly change its purpose. |
| 21290 | Multiple objects cannot convey identity, because we see them as different [Hume] |
| Full Idea: A mutiplicity of objects can never convey the idea of identity. The mind always pronounces the one not to be the other. | |
| From: David Hume (Treatise of Human Nature [1739], I.IV.2) | |
| A reaction: However, if we are talking on the phone about two objects we are viewing, such as two buildings, our descriptions might lead us to conclude that our objects are identical. Thus experience might imply identity. |
| 1207 | Both number and unity are incompatible with the relation of identity [Hume] |
| Full Idea: Both number and unity are incompatible with the relation of identity. | |
| From: David Hume (Treatise of Human Nature [1739], I.IV.2) |
| 21289 | 'An object is the same with itself' is meaningless; it expresses unity, not identity [Hume] |
| Full Idea: In that proposition 'an object is the same with itself', if the idea expressed by the word 'object' were no way distinguished from that meant by 'itself', we should really mean nothing. ...One single object conveys the idea of unity, not that of identity. | |
| From: David Hume (Treatise of Human Nature [1739], I.IV.2) | |
| A reaction: As far as I can see it is mathematicians who like self-identity, to justify x=x, which they need. To say 'this vase is identical with itself' is an empty locution. It expresses either unity or stability over time. See Idea 21292. |
| 21292 | Saying an object is the same with itself is only meaningful over a period of time [Hume] |
| Full Idea: We cannot, in any propriety of speech, say that an object is the same with itself, unless we mean that the object existent at one time is the same with itself at another time. | |
| From: David Hume (Treatise of Human Nature [1739], I.IV.2) | |
| A reaction: This seems correct, but the strict language of identity is superfluous when identifying stolen goods. 'This is my watch', not 'this watch is identical with my watch'. |
| 9428 | Nothing we clearly imagine is absolutely impossible [Hume] |
| Full Idea: 'Tis an established maxim in metaphysics, that whatever the mind clearly conceives includes the idea of possible existence, or in other words, that nothing we imagine is absolutely impossible. | |
| From: David Hume (Treatise of Human Nature [1739], I.II.2) | |
| A reaction: It is important to note that this empiricist approach to what is impossible requires that we 'clearly' conceive the possibility - but how do we evaluate whether we are being clear or not? |
| 4766 | Necessity only exists in the mind, and not in objects [Hume] |
| Full Idea: Necessity …is nothing but an internal impression of the mind, or a determination to carry our thoughts from one object to another. | |
| From: David Hume (Treatise of Human Nature [1739], I.III.16) | |
| A reaction: The classic statement of the empiricist position. Personally I don't believe it. Non-mental necessities are likely to be natural, or to be features of 'Platonic' objects. A big issue… |
| 13749 | Belief in impossible worlds may require dialetheism [Schaffer,J] |
| Full Idea: One motivation for dialetheism is the view that there are impossible worlds. | |
| From: Jonathan Schaffer (On What Grounds What [2009], 2.3) |
| 13740 | 'Moorean certainties' are more credible than any sceptical argument [Schaffer,J] |
| Full Idea: A 'Moorean certainty' is when something is more credible than any philosopher's argument to the contrary. | |
| From: Jonathan Schaffer (On What Grounds What [2009], 2.1) | |
| A reaction: The reference is to G.E. Moore's famous claim that the existence of his hand is more certain than standard sceptical arguments. It sounds empiricist, but they might be parallel rational truths, of basic logic or arithmetic. |
| 6526 | Hume says objects are not a construction, but an imaginative leap [Hume, by Robinson,H] |
| Full Idea: Hume's idea is that we move from private impressions to the physical world, not by an unconscious analytical construction but by a spontaneous imaginative leap. | |
| From: report of David Hume (Treatise of Human Nature [1739]) by Howard Robinson - Perception IX.6 | |
| A reaction: The idea that objects are 'constructions' seems to have originated with Russell. Hume seems closer to the actual process, which is virtually instantaneous. They both forget that you can follow up the construction or leap with a cool evaluation. |
| 6489 | Associationism results from having to explain intentionality just with sense-data [Robinson,H on Hume] |
| Full Idea: The limited theories of Berkeley and Hume have to be reductive, because they have to explain intentionality in terms of some kind of relation between sense-data; this predicament gives rise to the associationist accounts of psychology and meaning. | |
| From: comment on David Hume (Treatise of Human Nature [1739]) by Howard Robinson - Perception 1.4 | |
| A reaction: An illuminating explanation. Robinson seems to be implying that we should accept something like Searle's 'intrinsic' intentionality as basic, rather than intentionality built up from smaller components as Hume and Dennett suggest. |
| 6182 | Even Hume didn't include mathematics in his empiricism [Hume, by Kant] |
| Full Idea: Even Hume did not make empiricism so universal as to include mathematics in it. | |
| From: report of David Hume (Treatise of Human Nature [1739]) by Immanuel Kant - Critique of Practical Reason Pref | |
| A reaction: Hume didn't actually exclude mathematics, and the notion of 'relations of ideas' is a pointer. Subsequent empiricist have offered promising accounts. Personally I like the idea that patterns are the key idea. |
| 12417 | Mathematicians only accept their own proofs when everyone confims them [Hume] |
| Full Idea: There is no Mathematician so expert as to place entire confidence in any truth upon his discovery of it. ..Every time he runs over his proofs his confidence encreases, ..and is rais'd to perfection by the applause of the learned world. | |
| From: David Hume (Treatise of Human Nature [1739], IV.1.4) | |
| A reaction: [compressed] Quoted by Kitcher, and a nice example of the social nature of 'warrants', even in mathematics. It was illustrated well in the 1990s by the story of the proof of Fermat's Last Theorem by Andrew Wiles. |
| 5548 | Hume became a total sceptic, because he believed that reason was a deception [Hume, by Kant] |
| Full Idea: David Hume gave way entirely to scepticism, since he believed himself to have discovered in what is generally held to be reason a deception of our faculty of cognition. | |
| From: report of David Hume (Treatise of Human Nature [1739]) by Immanuel Kant - Critique of Pure Reason B128 | |
| A reaction: Unfair to Hume, who was very opposed to global scepticism (see Ideas 2240 and 2241), and voted only for 'mitigated scepticism' (see Idea 2242). On the other hand, there is no greater opposition in philosophy than Kant and Hume on 'pure reason'. |
| 7446 | The idea of inductive evidence, around 1660, made Hume's problem possible [Hume, by Hacking] |
| Full Idea: Hume's sceptical problem of induction could not have arisen much before 1660, for there was no concept of inductive evidence in terms of which to raise it. | |
| From: report of David Hume (Treatise of Human Nature [1739]) by Ian Hacking - The Emergence of Probability Cont 19 | |
| A reaction: Hacking is the expert, but Ideas 1683 and 1886 suggest there was some thinking on the problem in the ancient world. The worry about whether the future would be like the past must occasionally have bothered someone. |
| 21806 | Memory, senses and understanding are all founded on the imagination [Hume] |
| Full Idea: The memory, senses, and understanding are all of them founded on the imagination, or the vivacity of our ideas. | |
| From: David Hume (Treatise of Human Nature [1739], I.IV.7.3), quoted by Stephan Schmid - Faculties in Early Modern Philosophy 5 | |
| A reaction: He seems to have in mind his theory of associations, which are not rational. |
| 3819 | Hume's 'bundle' won't distinguish one mind with ten experiences from ten minds [Searle on Hume] |
| Full Idea: Hume's thought that each perception is separate and distinct cannot be right, because then we can't distinguish between one consciousness with ten experiences and ten different consciousnesses. | |
| From: comment on David Hume (Treatise of Human Nature [1739]) by John Searle - Rationality in Action Ch.3.VI | |
| A reaction: Why can't the only connection between them be that they all occur to the speaker who reports to them? How would I know if one of 'my' mental events actually belonged to a neighbour and had strayed. If it was coherent, I would accept it. |
| 1317 | A person is just a fast-moving bundle of perceptions [Hume] |
| Full Idea: I affirm of the rest of mankind, that they are nothing but a bundle or collection of different perceptions, which succeed each other with an inconceivable rapidity, and are in perpetual flux and movement. | |
| From: David Hume (Treatise of Human Nature [1739], I.IV.6) | |
| A reaction: Note that Hume is not just saying what we can know of ourselves, but is asserting a view of what we actually are. The minimal objection to this is to ask how we know that a perception is a member of one big bundle rather than several small ones. |
| 1331 | The parts of a person are always linked together by causation [Hume] |
| Full Idea: Whatever changes a person endures, his several parts are still connected by the relation of causation. | |
| From: David Hume (Treatise of Human Nature [1739], I.IV.6) | |
| A reaction: However, the opposite ends of the universe are linked together by causation, so that will not suffice for a theory of personal identity. One might try to specify a complex and tight network of causation (like a brain!) instead of just 'connection'. |
| 1388 | Hume gives us an interesting sketchy causal theory of personal identity [Perry on Hume] |
| Full Idea: I believe Hume offers an interesting if sketchy theory of personal identity, a causal theory, disguised as the revolutionary discovery that there is no such thing as personal identity | |
| From: comment on David Hume (Treatise of Human Nature [1739], I.IV.6) by John Perry - Introduction to 'Personal Identity' Intro | |
| A reaction: There is certainly a theory there, even though Hume ceased to believe in it, which is nowadays covered by the idea that personal identity is a 'fiction', an arbitrary idea that reifies the focus and direction of a bundle of mental events. |
| 21297 | A person is simply a bundle of continually fluctuating perceptions [Hume] |
| Full Idea: [People] are nothing but a bundle or collection of different perceptions, which succeed each other with an inconceivable rapidity, and are in a continual flux and movement. | |
| From: David Hume (Treatise of Human Nature [1739], I.IV.6) | |
| A reaction: Nowadays we must say that this misses the huge non-conscious aspect of what a person is. He seems to see all mental events as equal. Isn't the experience of deciding to focus on this sentence more 'central' than awareness of your feet? |
| 1316 | Introspection always discovers perceptions, and never a Self without perceptions [Hume] |
| Full Idea: I never can catch myself at any time without a perception, and never can observe any thing but the perception. | |
| From: David Hume (Treatise of Human Nature [1739], I.IV.6) | |
| A reaction: The first half can hardly be denied, but I think the second half is just false. What you observe is not just a raw neutral sense-datum, floating in nothing, but a sense-datum that is deeply coloured by MY interests, interpretations and values. |
| 1333 | Memory only reveals personal identity, by showing cause and effect [Hume] |
| Full Idea: Memory does not so much produce as discover personal identity, by showing us the relation of cause and effect among our different perceptions. | |
| From: David Hume (Treatise of Human Nature [1739], I.IV.6) | |
| A reaction: This is a rather strained proposal, as the revelation of a network of cause and effect seems to have no implications for personal identity (unless only 'I' could be the cause). |
| 1332 | We use memory to infer personal actions we have since forgotten [Hume] |
| Full Idea: We can extend the chain of causes acquired from memory, and consequently the identity of our persons beyond our memory, and can comprehend times, and circumstances, and actions, which we have entirely forgot. | |
| From: David Hume (Treatise of Human Nature [1739], I.IV.6) | |
| A reaction: If the principle is just that 'I am my consciousness' (including of my past), then why should not my consciousness of other people's pasts by included in my identity. How do I know that images in my consciousness are MY memories? |
| 21305 | Memory not only reveals identity, but creates it, by producing resemblances [Hume] |
| Full Idea: The memory not only discovers the identity [of the mind], but also contributes to its production, by producing the relation of resemblance among the perceptions | |
| From: David Hume (Treatise of Human Nature [1739], I.IV.6) | |
| A reaction: This is Hume battling to explain personal identity by his principles of association. He discount 'contiguity'. He doesn't explain how memory creates resemblances. Is not resemblance of idea to fact required in order to remember? |
| 21307 | Who thinks that because you have forgotten an incident you are no longer that person? [Hume] |
| Full Idea: Who will affirm, because he has entirely forgot the incidents of past days, that the present self is not the same person with the self of that time? And by that means overturn all the most established notions of personal identity? | |
| From: David Hume (Treatise of Human Nature [1739], I.IV.6) | |
| A reaction: This is a swipe at one of Locke's most controversial claims (especially when applied to incidents of criminal behaviour). Hume says memory constitutes this identity, but Locke's view says it merely reveals identity. |
| 21306 | Causation unites our perceptions, by producing, destroying and modifying each other [Hume] |
| Full Idea: As to causation, the true idea of the human mind is to consider it as a system of different perceptions, which are linked together by the relation of cause and effect, and mutually produce, destroy, influence and modify each other. | |
| From: David Hume (Treatise of Human Nature [1739], I.IV.6) | |
| A reaction: He suggests that the associations of memory and causation might be sufficient to produce identity of the mind, and he gives the priority to memory. Eventually the good empiricist despairs because you cannot experience the links. |
| 21294 | A continuous lifelong self must be justified by a single sustained impression, which we don't have [Hume] |
| Full Idea: If any impression gives rise to the idea of self, that impression must continue invariably the same, through the whole course of our lives; since self is supposed to exist after that manner. But there is no impression constant and invariable. | |
| From: David Hume (Treatise of Human Nature [1739], I.IV.6) | |
| A reaction: This is a rather dogmatic application of the requirement that all knowledge must be founded in experience. It fails to recognise that knowledge of the thing having the experiences is a rather special case. We must ask for the best explanation. |
| 21295 | When I introspect I can only observe my perceptions, and never a self which has them [Hume] |
| Full Idea: When I enter most intimately into myself I always stumble on some particular perception or other, of heat or cold, love or hatred, pain or pleasure. I never can catch myself at any time without a perception, and never observe any thing but the perception. | |
| From: David Hume (Treatise of Human Nature [1739], I.IV.6) | |
| A reaction: It isn't like looking for your car in the car park. The prior question should be: assuming you do have a persisting self, what would you expect introspection to reveal about it? |
| 21298 | We pretend our perceptions are continuous, and imagine a self to fill the gaps [Hume] |
| Full Idea: We feign the continued existence of the perceptions of our senses, to remove their interruption; and run into the notion of a soul, and self, and substance, to disguise the variation. | |
| From: David Hume (Treatise of Human Nature [1739], I.IV.6) | |
| A reaction: Modern neuroscience (according to Dennett) endorses this, because the brain continually fills in gaps in experience (as it fills in the blindspot during normal vision). |
| 21304 | Identity in the mind is a fiction, like that fiction that plants and animals stay the same [Hume] |
| Full Idea: The identity we ascribe to the mind is only a fictitious one, and of a like kind with that we ascribe to vegetable and animal bodies. It cannot therefore have a different origin, but must proceed from a like operation of the imagination upon like objects. | |
| From: David Hume (Treatise of Human Nature [1739], I.IV.6) | |
| A reaction: Sustained purpose is Hume's common factor. Is the identity over time ascribed to the body of a single animal nothing more than a fiction? It is a wise ascription, compared to stupid ascriptions to gerrymandered objects. |
| 20030 | If one event causes another, the two events must be wholly distinct [Hume, by Wilson/Schpall] |
| Full Idea: Hume's maxim is that if one event cause another, then the two events must be wholly distinct. | |
| From: report of David Hume (Treatise of Human Nature [1739]) by Wilson,G/Schpall,S - Action 3 | |
| A reaction: [Anyone know the original reference?] So we are not allowed to say that one part of an event caused another. The charged caused the victory, so they are two events, but in another context the whole battle is one event. |
| 6692 | For Hume, practical reason has little force, because we can always modify our desires [Hume, by Graham] |
| Full Idea: In Hume's account of action, practical reason is not a very forceful guide to conduct, since we can escape its demands by abandoning or modifying our desires. | |
| From: report of David Hume (Treatise of Human Nature [1739]) by Gordon Graham - Eight Theories of Ethics Ch.6 | |
| A reaction: Presumably a desire can be a good reason, and we can passionately desire to be rational, etc., so this is a rather complex issue. 'Pure reason' is not 'all-or-nothing', and neither is pure desire. |
| 8257 | Reason alone can never be a motive to any action of the will [Hume] |
| Full Idea: Reason alone can never be a motive to any action of the will. | |
| From: David Hume (Treatise of Human Nature [1739], II.III.3) | |
| A reaction: This is Hume's notorious total rejection of Socratic intellectualism, a stilleto in the back of the 'age of reason'. Hume thinks desire is the motivator. He's probably right. Why should truth motivate? See Idea 4421. |
| 22374 | You can only hold people responsible for actions which arise out of their character [Hume] |
| Full Idea: Where actions proceed not from some cause in the characters and dispositions of the person who performed them, they infix not themselves upon him, and can neither redound to his honour if good, nor infamy if evil. The action in itself may be blameable. | |
| From: David Hume (Treatise of Human Nature [1739], II.III.2), quoted by Philippa Foot - Free Will as Involving Determinism p.70 | |
| A reaction: I agree with Foot that this is wrong. Uncharacteristic actions still reflect on the person. The last sentence is wrong too. If you ignore the agent of an action, it can't be distinguished from a flash of lightning. |
| 22382 | We cannot discover vice by studying a wilful murder; that only arises from our own feelings [Hume] |
| Full Idea: Examine wilful murder and see if you can find the matter of fact called vice. You only find certain passions, motives, volitions and thoughts. There is no matter of fact in the case. You can never find it till you turn your reflexion into your own breast. | |
| From: David Hume (Treatise of Human Nature [1739], III.I.2), quoted by Philippa Foot - Hume on Moral Judgement p.77 | |
| A reaction: [...In you breast you find 'disapprobation'] The question Foot asks is whether the facts of the case are relevant to the disapprobation. If they are not, as Hume implies, then it would be rational to feel the same disapprobation about drinking coffee. |
| 4008 | Modern science has destroyed the Platonic synthesis of scientific explanation and morality [Hume, by Taylor,C] |
| Full Idea: From our modern perspective, the Platonic synthesis of scientific explanation and moral insight lies irrecoverably shattered by the rise of natural science. | |
| From: report of David Hume (Treatise of Human Nature [1739]) by Charles Taylor - Sources of the Self §3.2 | |
| A reaction: Modern attempts to challenge Hume's separation of fact from value have failed, but a return to the Greek perspective presents a plausible alternative. |
| 8067 | The problem of getting to 'ought' from 'is' would also apply in getting to 'owes' or 'needs' [Anscombe on Hume] |
| Full Idea: Hume's objection to passing from 'is' to 'ought' would equally apply to passing from 'is' to 'owes' or from 'is' to 'needs'. | |
| From: comment on David Hume (Treatise of Human Nature [1739]) by G.E.M. Anscombe - Modern Moral Philosophy p.176 | |
| A reaction: Profound and important. The empirical and emotivist (nay, nihilist) clinging to the total independence of duties from facts crumbles when looking at facts of human nature or of social groups. Creatures ought to feed; societies ought to flourish. |
| 4578 | You can't move from 'is' to 'ought' without giving some explanation or reason for the deduction [Hume] |
| Full Idea: In many writers I find that instead of the usual propositions 'is' and 'is not', I then find no proposition that is not connected with an 'ought' or an 'ought not'. It is necessary that a reason be given for how one can be a deduction from the other. | |
| From: David Hume (Treatise of Human Nature [1739], III.1.1) | |
| A reaction: A huge claim, the basis of the value-free modern scientific world view. Possible escapes are Greek virtue theory, or Kantian principles, or some sort of a priori values (as in Charles Taylor). |
| 3650 | Total selfishness is not irrational [Hume] |
| Full Idea: It is not contrary to reason to prefer the destruction of the whole world to the scratching of my finger. | |
| From: David Hume (Treatise of Human Nature [1739], II.III.ii) | |
| A reaction: A famous idea, and the embodiment of moral nihilism. I say nothing could ever refute someone who held such a view. No moral theory can force someone to care, if they just don't. |
| 14301 | We have no good concept of solidity or matter, because accounts of them are all circular [Hume] |
| Full Idea: In order to form an idea of solidity, we must conceive two bodies pressing on each other without penetration. ..The ideas of secondary qualities are excluded, and the idea of motion depends on extension. This leaves us no just idea of solidity or matter. | |
| From: David Hume (Treatise of Human Nature [1739], I.IV.4), quoted by Stephen Mumford - Dispositions 02.3 | |
| A reaction: [compressed] For me these kind of strict empiricist arguments always recede when you accept the notion of an inference to be best explanation. We have some sort of notion of 'matter', but here the physicist seems to take over. |
| 8382 | For Hume a constant conjunction is both necessary and sufficient for causation [Hume, by Crane] |
| Full Idea: Hume held that constant conjunction between As and Bs is both necessary and sufficient for a causal relation. If As and Bs are conjoined that is sufficient for a causal relation; if A and B are causally related, necessarily they are constantly conjoined. | |
| From: report of David Hume (Treatise of Human Nature [1739]) by Tim Crane - Causation 1.2.2 | |
| A reaction: A helpful connection between Hume and the modern debate about conditions for causation (e.g. Mackie). It sounds as if, to spot the necessary condition, you need to independently see that A and B are causally related, which regularity does not allow. |
| 19274 | Hume seems to presuppose necessary connections between mental events [Kripke on Hume] |
| Full Idea: A well-known objection to Hume's analysis of causation is that he presupposes necessary connections between mental events in the theory. | |
| From: comment on David Hume (Treatise of Human Nature [1739]) by Saul A. Kripke - Wittgenstein on Rules and Private Language n 87 | |
| A reaction: Are these the associations that occur within the mind? I'm not clear about the objection, but record it for interest. |
| 21296 | If all of my perceptions were removed by death, nothing more is needed for total annihilation [Hume] |
| Full Idea: Were all my perceptions removed by death, and I could I neither think nor feel nor see nor love nor hate, after the dissolution of my body, I should be enitrely annihilated, nor do I conceive what is further requisite to make me a perfect non-entity. | |
| From: David Hume (Treatise of Human Nature [1739], I.IV.6) | |
| A reaction: 'A perfect non-entity'. How about that for an eighteenth century rejection of immortality of the soul? In the context, his point is that the has no enduring self, apart from this range of experiences. |