31 ideas
| 19066 | Philosophy aims to understand the world, through ordinary experience and science [Dummett] |
| Full Idea: Philosophy is an attempt to understand the world, as it is revealed to us both in our ordinary experience and by the discoveries and theories of science. | |
| From: Michael Dummett (The Justification of Deduction [1973], p.311) | |
| A reaction: I don't see a sharp division between 'ordinary' and 'scientific'. I really like this idea, first because it makes 'understanding' central, and second because it wants both revelations. In discussing matter and time, there is too much emphasis on science. |
| 17651 | Without words or other symbols, we have no world [Goodman] |
| Full Idea: We can have words without a world but no world without words or other symbols. | |
| From: Nelson Goodman (Ways of Worldmaking [1978], 1.3) | |
| A reaction: Goodman seems to have a particularly extreme version of the commitment to philosophy as linguistic. Non-human animals have no world, it seems. |
| 19067 | A successful proof requires recognition of truth at every step [Dummett] |
| Full Idea: For a demonstration to be cogent it is necessary that the passage from step to step involve a recognition of truth at each line. | |
| From: Michael Dummett (The Justification of Deduction [1973], p.313) | |
| A reaction: Dummett cited Quine (esp. 1970) as having an almost entirely syntactic view of logic. Rumfitt points out that logic can move validly from one falsehood to another. Even a 'proof' might detour into falsehood, but it would not be a 'canonical' proof! |
| 17652 | Truth is irrelevant if no statements are involved [Goodman] |
| Full Idea: Truth pertains solely to what is said ...For nonverbal versions and even for verbal versions without statements, truth is irrelevant. | |
| From: Nelson Goodman (Ways of Worldmaking [1978], 1.5) | |
| A reaction: Goodman is a philosopher of language (like Dummett), but I am a philosopher of thought (like Evans). The test, for me, is whether truth is applicable to the thought of non-human animals. I take it to be obvious that it is applicable. |
| 19060 | Truth-tables are dubious in some cases, and may be a bad way to explain connective meaning [Dummett] |
| Full Idea: It is arguable whether two-valued truth tables give correct meanings for certain sentential operators, and even whether they constitute legitimate explanations of any possible sentential operators. | |
| From: Michael Dummett (The Justification of Deduction [1973], p.294) | |
| A reaction: See 'Many-valued logic' for examples of non-binary truth tables. Presumably logicians should aspire to make their semantics precise, as well as their syntax. |
| 11066 | Deduction is justified by the semantics of its metalanguage [Dummett, by Hanna] |
| Full Idea: For Dummett the semantics of the metalanguage is the external and objective source of the justification of deduction. | |
| From: report of Michael Dummett (The Justification of Deduction [1973]) by Robert Hanna - Rationality and Logic 3.4 | |
| A reaction: This is offered as an answer to the Lewis Carroll problem that justifying deduction seems to need deduction, thus leading to a regress. [There is a reply to Dummett by Susan Haack] |
| 19058 | Syntactic consequence is positive, for validity; semantic version is negative, with counterexamples [Dummett] |
| Full Idea: A plausible account is that the syntactic notion of consequence is for positive results, that some form of argument is valid; the semantic notion is required for negative results, that some argument is invalid, because a counterexample can be found. | |
| From: Michael Dummett (The Justification of Deduction [1973], p.292) | |
| A reaction: This rings true for the two strategies of demonstration, the first by following the rules in steps, the second by using your imagination (or a tableau) to think up problems. |
| 19063 | Beth trees show semantics for intuitionistic logic, in terms of how truth has been established [Dummett] |
| Full Idea: Beth trees give a semantics for intuitionistic logic, by representing sentence meaning in terms of conditions under which it is recognised to have been established as true. | |
| From: Michael Dummett (The Justification of Deduction [1973], p.305) |
| 19059 | In standard views you could replace 'true' and 'false' with mere 0 and 1 [Dummett] |
| Full Idea: Nothing is lost, on this view, if in the standard semantic treatment of classical sentential logic, we replace the standard truth-values 'true' and 'false' by the numbers 0 and 1. | |
| From: Michael Dummett (The Justification of Deduction [1973], p.294) | |
| A reaction: [A long context will explain 'on this view'] He is discussing the relationship of syntactic and semantic consequence, and goes on to criticise simple binary truth-table accounts of connectives. Semantics on a computer would just be 0 and 1. |
| 19062 | Classical two-valued semantics implies that meaning is grasped through truth-conditions [Dummett] |
| Full Idea: The standard two-valued semantics for classical logic involves a conception under which to grasp the meaning of a sentence is to apprehend the conditions under which it is, or is not, true. | |
| From: Michael Dummett (The Justification of Deduction [1973], p.305) | |
| A reaction: The idea is that you only have to grasp the truth tables for sentential logic, and that needs nothing more than knowing whether a sentence is true or false. I'm not sure where the 'conditions' creep in, though. |
| 19065 | Soundness and completeness proofs test the theory of meaning, rather than the logic theory [Dummett] |
| Full Idea: A proof of soundess or completeness is a test, not so much of the logical theory to which it applies, but of the theory of meaning which underlies the semantics. | |
| From: Michael Dummett (The Justification of Deduction [1973], p.310) | |
| A reaction: These two types of proof concern how the syntax and the semantics match up, so this claim sounds plausible, though I tend to think of them as more like roadworthiness tests for logic, checking how well they function. |
| 17656 | Being primitive or prior always depends on a constructional system [Goodman] |
| Full Idea: Nothing is primitive or derivationally prior to anything apart from a constructional system. | |
| From: Nelson Goodman (Ways of Worldmaking [1978], 1.4c) | |
| A reaction: Something may be primitive not just because we can't be bothered to analyse it any further, but because even God couldn't analyse it. Maybe. |
| 17661 | We don't recognise patterns - we invent them [Goodman] |
| Full Idea: Recognising patterns is very much a matter of inventing or imposing them. | |
| From: Nelson Goodman (Ways of Worldmaking [1978], 1.7) | |
| A reaction: I take this to be false. |
| 17659 | Reality is largely a matter of habit [Goodman] |
| Full Idea: Reality in a world, like realism in a picture, is largely a matter of habit. | |
| From: Nelson Goodman (Ways of Worldmaking [1978], 1.6) | |
| A reaction: I'm a robust realist, me, but I sort of see what he means. We become steeped in unspoken conventions about how we take our world to be, and filter out anything that conflicts with it. |
| 17657 | We build our world, and ignore anything that won't fit [Goodman] |
| Full Idea: We dismiss as illusory or negligible what cannot be fitted into the architecture of the world we are building. | |
| From: Nelson Goodman (Ways of Worldmaking [1978], 1.4d) | |
| A reaction: I'm trying to think of an example of this, but can't. Maybe poor people are invisible to the rich? |
| 17654 | A world can be full of variety or not, depending on how we sort it [Goodman] |
| Full Idea: A world may be unmanageably heterogeneous or unbearably monotonous according to how events are sorted into kinds. | |
| From: Nelson Goodman (Ways of Worldmaking [1978], 1.4a) | |
| A reaction: We might expect this from the man who invented 'grue', which allows you to classify things that change colour with things that don't. Could you describe a bird as 'might have been a fish', and classify it with fish? ('Projectible'?) |
| 7720 | Two things can only resemble one another in some respect, and that may reintroduce a universal [Lowe] |
| Full Idea: A problem for resemblance nominalism is that in saying that two particulars 'resemble' one another, it is necessary to specify in what respect they do so (e.g. colour, shape, size), and this threatens to reintroduce what appears to be talk of universals. | |
| From: E.J. Lowe (Locke on Human Understanding [1995], Ch.7) | |
| A reaction: We see resemblance between faces instantly, long before we can specify the 'respects' of the resemblance. This supports the Humean hard-wired view of resemblance, rather than some appeal to Platonic universals. |
| 7712 | On substances, Leibniz emphasises unity, Spinoza independence, Locke relations to qualities [Lowe] |
| Full Idea: Later philosophers emphasised different strands of Aristotle's concept of substances: Leibniz (in his theory of monads) emphasised their unity; Spinoza emphasised their ontological independence; Locke emphasised their role in relation to qualities. | |
| From: E.J. Lowe (Locke on Human Understanding [1995], Ch.4) | |
| A reaction: Note that this Aristotelian idea had not been jettisoned in the late seventeenth century, unlike other Aristotelianisms. I think it is only with the success of atomism in chemistry that the idea of substance is forced to recede. |
| 17653 | Things can only be judged the 'same' by citing some respect of sameness [Goodman] |
| Full Idea: Identification rests upon organization into entities and kinds. The response to the question 'Same or not the same?' must always be 'Same what?'. ...Identity or constancy in a world is identity with respect to what is within that world as organised. | |
| From: Nelson Goodman (Ways of Worldmaking [1978], 1.4a) | |
| A reaction: And the gist of his book is that 'organised' is done by us, not by the world. He seems to be committed to the full Geachean relative identity, rather than the mere Wigginsian relative individuation. An unfashionable view! |
| 7710 | Perception is a mode of belief-acquisition, and does not involve sensation [Lowe] |
| Full Idea: According to one school of thought, perception is simply a mode of belief-acquisition,and there is no reason to suppose that any element of sensation is literally involved in perception. | |
| From: E.J. Lowe (Locke on Human Understanding [1995], Ch.3) | |
| A reaction: Blindsight would be an obvious supporting case for this view. I think this point is crucial in understanding what is wrong with Jackson's 'knowledge argument' (involving Mary, see Idea 7377). Sensation gives knowledge, so it can't be knowledge. |
| 7711 | Science requires a causal theory - perception of an object must be an experience caused by the object [Lowe] |
| Full Idea: Only a causal theory of perception will respect the facts of physiology and physics ...meaning a theory which maintains that for a subject to perceive a physical object the subject should enjoy some appropriate perceptual experience caused by the object. | |
| From: E.J. Lowe (Locke on Human Understanding [1995], Ch.3) | |
| A reaction: If I hallucinate an object, then presumably I am not allowed to say that I 'perceive' it, but that seems to make the causal theory an idle tautology. If we are in virtual reality then there aren't any objects. |
| 17660 | Discovery is often just finding a fit, like a jigsaw puzzle [Goodman] |
| Full Idea: Discovery often amounts, as when I place a piece in a jigsaw puzzle, not to arrival at a proposition for declaration or defense, but to finding a fit. | |
| From: Nelson Goodman (Ways of Worldmaking [1978], 1.7) | |
| A reaction: I find Goodman's views here pretty alien, but I like this bit. Coherence really rocks. |
| 17658 | Users of digital thermometers recognise no temperatures in the gaps [Goodman] |
| Full Idea: To use a digital thermometer with readings in tenths of a degree is to recognise no temperature as lying between 90 and 90.1 degrees. | |
| From: Nelson Goodman (Ways of Worldmaking [1978], 1.4d) | |
| A reaction: This appears to be nonsense, treating users of digital thermometers as if they were stupid. No one thinks temperatures go up and down in quantum leaps. We all know there is a gap between instrument and world. (Very American, I'm thinking!) |
| 17650 | We lack frames of reference to transform physics, biology and psychology into one another [Goodman] |
| Full Idea: We have no neat frames of reference, no ready rules for transforming physics, biology and psychology into one another. | |
| From: Nelson Goodman (Ways of Worldmaking [1978], 1.2) |
| 17655 | Grue and green won't be in the same world, as that would block induction entirely [Goodman] |
| Full Idea: Grue cannot be a relevant kind for induction in the same world as green, for that would preclude some of the decisions, right or wrong, that constitute inductive inference. | |
| From: Nelson Goodman (Ways of Worldmaking [1978], 1.4b) | |
| A reaction: This may make 'grue' less mad than I thought it was. I always assume we are slicing the world as 'green, blue and grue'. I still say 'green' is a basic predicate of experience, but 'grue' is amenable to analysis. |
| 19061 | An explanation is often a deduction, but that may well beg the question [Dummett] |
| Full Idea: An explanation is often a deductive argument, with the fact needing explaining as its conclusion. ...But the conclusion is usually given in advance, and we may only believe the premisses because they plausibly explain the conclusion. | |
| From: Michael Dummett (The Justification of Deduction [1973], p.296) | |
| A reaction: [compressed (Dummett's wordy prose cries out for it!)] I suppose this works better in mathematics, which is central to Dummett's interests. In the real world the puzzle is not usually logically implied by its explanation. |
| 7714 | Personal identity is a problem across time (diachronic) and at an instant (synchronic) [Lowe] |
| Full Idea: There is the question of the identity of a person over or across time ('diachronic' personal identity), and there is also the question of what makes for personal identity at a time ('synchronic' personal identity). | |
| From: E.J. Lowe (Locke on Human Understanding [1995], Ch.5) | |
| A reaction: This seems to me to be the first and most important distinction in the philosophy of personal identity, and they regularly get run together. Locke, for example, has an account of synchronic identity, which is often ignored. It applies to objects too. |
| 7715 | Mentalese isn't a language, because it isn't conventional, or a means of public communication [Lowe] |
| Full Idea: 'Mentalese' would be neither conventional nor a means of public communication so that even to call it a language is seriously misleading. | |
| From: E.J. Lowe (Locke on Human Understanding [1995], Ch.7) | |
| A reaction: It is, however, supposed to contain symbolic representations which are then used as tokens for computation, so it seems close to a language, if (for example) symbolic logic or mathematics were accepted as languages. But who understands it? |
| 7722 | If meaning is mental pictures, explain "the cat (or dog!) is NOT on the mat" [Lowe] |
| Full Idea: If meaning is a private mental picture, what does 'the cat is NOT on the mat' mean, and how does it differ from 'the dog is not on the mat?'. | |
| From: E.J. Lowe (Locke on Human Understanding [1995], Ch.7) | |
| A reaction: Not insurmountable. We picture an empty mat, combined with a cat (or whatever) located somewhere else. A mental 'picture' of something shouldn't be contrued as a single image in a neat black frame. |
| 19064 | Holism is not a theory of meaning; it is the denial that a theory of meaning is possible [Dummett] |
| Full Idea: In the sense of giving a model for the content of a sentence, its representative power, holism is not a theory of meaning; it is the denial that a theory of meaning is possible. | |
| From: Michael Dummett (The Justification of Deduction [1973], p.309) | |
| A reaction: This will obviously be because sentences just don't have meaning in isolation, so their meaning can't be given in terms of the sentences. |
| 17649 | If the world is one it has many aspects, and if there are many worlds they will collect into one [Goodman] |
| Full Idea: If there is but one world, it embraces a multiplicity of contrasting aspects; if there are many worlds, the collection of them all is one. One world may be taken as many, or many worlds taken as one; whether one or many depends on the way of taking. | |
| From: Nelson Goodman (Ways of Worldmaking [1978], 1.2) | |
| A reaction: He cites 'The Pluralistic Universe' by William James for this idea. The idea is that the distinction 'evaporates under analysis'. Parmenides seems to have thought that no features could be distinguished in the true One. |