38 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. |
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! |
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. |
6504 | For physicalists, the only relations are spatial, temporal and causal [Robinson,H] |
Full Idea: Spatial, temporal and causal relations are the only respectable candidates for relations for a physicalist. | |
From: Howard Robinson (Perception [1994], V.4) | |
A reaction: This seems to be true, and is an absolutely crucial principle upon which any respectable physicalist account of the world must be built. It means that physicalists must attempt to explain all mental events in causal terms. |
6520 | If reality just has relational properties, what are its substantial ontological features? [Robinson,H] |
Full Idea: Some thinkers claim the physical world consists just of relational properties - generally of active powers or fields; ..but an ontology of mutual influences is not an ontology at all unless the possessors of the influence have more substantial features. | |
From: Howard Robinson (Perception [1994], IX.3) | |
A reaction: I think this idea is one of the keys to wisdom. It is the same problem with functional explanations - you are left asking WHY this thing can have this particular function. Without the buck stopping at essences you are chasing your explanatory tail. |
6485 | When a red object is viewed, the air in between does not become red [Robinson,H] |
Full Idea: When the form of red passes from an object to the eye, the air in between does not become red. | |
From: Howard Robinson (Perception [1994], 1.2) | |
A reaction: This strikes me as a crucial and basic fact which must be faced by any philosopher offering a theory of perception. I would have thought it instantly eliminated any sort of direct or naïve realism. The quale of red is created by my brain. |
6521 | Representative realists believe that laws of phenomena will apply to the physical world [Robinson,H] |
Full Idea: One thing which is meant by saying that the phenomenal world represents or resembles the transcendental physical world is that the scientific laws devised to apply to the former, if correct, also apply (at least approximately) to the latter. | |
From: Howard Robinson (Perception [1994], IX.3) | |
A reaction: This is not, of course, an argument, or a claim which can be easily substantiated, but it does seem to be a nice statement of a central article of faith for representative realists. The laws of the phenomenal world are the only ones we are going to get. |
6509 | Representative realists believe some properties of sense-data are shared by the objects themselves [Robinson,H] |
Full Idea: A representative realist believes that at least some of the properties that are ostensively demonstrable in virtue of being exemplified in sense-data are of the same kind as some of those exemplified in physical objects. | |
From: Howard Robinson (Perception [1994], VII.5) | |
A reaction: It is hard to pin down exactly what is being claimed here. Locke's primary qualities will obviously qualify, but could properties be 'exemplified' in sense-data without them actually being the same as those of the objects? |
18988 | Behind the bare phenomenal facts there is nothing [Wright,Ch] |
Full Idea: Behind the bare phenomenal facts, as my tough-minded old friend Chauncey Wright, the great Harvard empiricist of my youth, used to say, there is nothing. | |
From: Chauncey Wright (talk [1870]), quoted by William James - Pragmatism - eight lectures Lec 7 | |
A reaction: This is the best slogan for strong phenomenalism ever coined! It also seems to fit David Lewis's approach to philosophy, as the pure study of the mosaic of experiences. |
6522 | Phenomenalism can be theistic (Berkeley), or sceptical (Hume), or analytic (20th century) [Robinson,H] |
Full Idea: It is useful to identify three kinds of phenomenalism: theistic, sceptical and analytic; the first is represented by Berkeley, the second by Hume, and the third by most twentieth-century phenomenalists. | |
From: Howard Robinson (Perception [1994], IX.4) | |
A reaction: In Britain the third group is usually represented by A.J.Ayer. My simple objection to all phenomenalists is that they are intellectual cowards because they won't venture to give an explanation of the phenomena which confront them. |
6502 | Can we reduce perception to acquisition of information, which is reduced to causation or disposition? [Robinson,H] |
Full Idea: Many modern physicalists first analyse perception as no more than the acquisition of beliefs or information through the senses, and then analyse belief and the possession of information in causal or dispositional terms. | |
From: Howard Robinson (Perception [1994], V.1) | |
A reaction: (He mentions Armstrong, Dretske and Pitcher). A reduction to dispositions implies behaviourism. This all sounds more like an eliminativist strategy than a reductive one. I would start by saying that perception is only information after interpretation. |
6513 | Would someone who recovered their sight recognise felt shapes just by looking? [Robinson,H] |
Full Idea: Molyneux's Problem is whether someone who was born blind and acquired sight would be able to recognise, on sight, which shapes were which; that is, would they see which shape was the one that felt so-and-so? | |
From: Howard Robinson (Perception [1994], VIII.7) | |
A reaction: (Molyneux wrote a letter to John Locke about this). It is a good question, and much discussed in modern times. My estimation is that the person would recognise the shapes. We are partly synaesthetic, and see sharpness as well as feeling it. |
6512 | Secondary qualities have one sensory mode, but primary qualities can have more [Robinson,H] |
Full Idea: Primary qualities and secondary qualities are often distinguished on the grounds that secondaries are restricted to one sensory modality, but primaries can appear in more. | |
From: Howard Robinson (Perception [1994], VIII.7) | |
A reaction: This distinction seems to me to be accurate and important. It is not just that the two types are phenomenally different - it is that the best explanation is that the secondaries depend on their one sense, but the primaries are independent. |
6497 | We say objects possess no intrinsic secondary qualities because physicists don't need them [Robinson,H] |
Full Idea: The idea that objects do not possess secondary qualities intrinsically rests on the thought that they do not figure in the physicist's account of the world; ..as they are causally idle, no purpose is served by attributing them to objects. | |
From: Howard Robinson (Perception [1994], III.1) | |
A reaction: On the whole I agree with this, but colours (for example) are not causally idle, as they seem to affect the behaviour of insects. They are properties which can only have a causal effect if there is a brain in their vicinity. Physicists ignore brains. |
6494 | If objects are not coloured, and neither are sense-contents, we are left saying that nothing is coloured [Robinson,H] |
Full Idea: If there are good reasons for thinking that physical objects are not literally coloured, and one also refuses to attribute them to sense-contents, then one will have the bizarre theory (which has been recently adopted) that nothing is actually coloured. | |
From: Howard Robinson (Perception [1994], 1.7) | |
A reaction: It seems to me that objects are not literally coloured, that the air in between does not become coloured, and that my brain doesn't turn a funny colour, so that only leaves colour as an 'interior' feature of certain brain states. That's how it is. |
6499 | Shape can be experienced in different ways, but colour and sound only one way [Robinson,H] |
Full Idea: Shape can be directly experienced by either touch or sight, which are subjectively different; but colour and sound can be directly experienced only through experiences which are subjectively like sight and hearing. | |
From: Howard Robinson (Perception [1994], III.1) | |
A reaction: This seems to be a key argument in support of the distinction between primary and secondary qualities. It seems to me that the distinction may be challenged and questioned, but to deny it completely (as Berkeley and Hume do) is absurd. |
6500 | If secondary qualities match senses, would new senses create new qualities? [Robinson,H] |
Full Idea: As secondary qualities are tailored to match senses, a proliferation of senses would lead to a proliferation of secondary qualities. | |
From: Howard Robinson (Perception [1994], III.1) | |
A reaction: One might reply that if we experienced, say, magnetism, we would just be discerning a new fine grained primary quality, not adding something new to the ontological stock of properties in the world. It is a matter of HOW we experience the magnetism. |
6484 | Most moderate empiricists adopt Locke's representative theory of perception [Robinson,H] |
Full Idea: The representative theory of perception is found in Locke, and is adopted by most moderate empiricists. | |
From: Howard Robinson (Perception [1994], 1.2) | |
A reaction: This is, I think, my own position. Anything less than fairly robust realism strikes me as being a bit mad (despite Berkeley's endless assertions that he is preaching common sense), and direct realism seems obviously false. |
6508 | Sense-data leads to either representative realism or phenomenalism or idealism [Robinson,H] |
Full Idea: The sense-datum theorist is either a representative realist or a phenomenalist (with which we can classify idealism for present purposes). | |
From: Howard Robinson (Perception [1994], VII.5) | |
A reaction: The only alternative to these two positions seems to be some sort of direct realism. I class myself as a representative realist, as this just seems (after a very little thought about colour blindness) to be common sense. I'm open to persuasion. |
6480 | Sense-data do not have any intrinsic intentionality [Robinson,H] |
Full Idea: I understand sense-data as having no intrinsic intentionality; that is, though it may suggest, by habit, things beyond it, in itself it possesses only sensible qualities which do not refer beyond themselves. | |
From: Howard Robinson (Perception [1994], 1.1) | |
A reaction: This seems right, as the whole point of proposing sense-data was as something neutral between realism and anti-realism |
6482 | For idealists and phenomenalists sense-data are in objects; representative realists say they resemble objects [Robinson,H] |
Full Idea: For idealists and phenomenalists sense-data are part of physical objects, for objects consist only of actual or actual and possible sense-data; representative realists say they just have an abstract and structural resemblance to objects. | |
From: Howard Robinson (Perception [1994], 1.1) | |
A reaction: He puts Berkeley, Hume and Mill in the first group, and Locke in the second. Russell belongs in the second. The very fact that there can be two such different theories about the location of sense-data rather discredits the whole idea. |
6505 | Sense-data are rejected because they are a veil between us and reality, leading to scepticism [Robinson,H] |
Full Idea: Resistance to the sense-datum theory is inspired mainly by the fear that such data constitute a veil of perception which stands between the observer and the external world, threatening scepticism, or even solipsism. | |
From: Howard Robinson (Perception [1994], VII.1) | |
A reaction: It is very intellectually dishonest to reject any theory because it leads to scepticism or relativism. This is a common failing among quite good professional philosophers. See Idea 241. |
6506 | 'Sense redly' sounds peculiar, but 'senses redly-squarely tablely' sounds far worse [Robinson,H] |
Full Idea: 'Sense redly' sounds peculiar, but 'senses redly-squarely' or 'red-squarely' or 'senses redly-squarely-tablely' and other variants sound far worse. | |
From: Howard Robinson (Perception [1994], VII.5) | |
A reaction: This is a comment on the adverbial theory, which is meant to replace representative theories based on sense-data. The problem is not that it sounds weird; it is that while plain red can be a mode of perception, being a table obviously can't. |
6507 | Adverbialism sees the contents of sense-experience as modes, not objects [Robinson,H] |
Full Idea: The defining claim of adverbialism is that the contents of sense-experience are modes, not objects, of sensory activity. | |
From: Howard Robinson (Perception [1994], VII.5) | |
A reaction: This seems quite a good account of simple 'modes' like colour, but not so good when you instantly perceive a house. It never seems wholly satisfactory to sidestep the question of 'what are you perceiving when you perceive red or square?' |
6511 | If there are only 'modes' of sensing, then an object can no more be red or square than it can be proud or lazy. [Robinson,H] |
Full Idea: If only modes of sensing are ostensively available, ..then it is a category mistake to see any resemblance between what is available and properties of bodies; one could as sensibly say that a physical body is proud or lazy as that it is red or square. | |
From: Howard Robinson (Perception [1994], VII.5) | |
A reaction: This is an objection to the 'adverbial' theory of perception. It looks to me like a devastating objection, if the theory is meant to cover primary qualities as well as secondary. Red could be a mode of perception, but not square, surely? |
6515 | An explanation presupposes something that is improbable unless it is explained [Robinson,H] |
Full Idea: Any search for an explanation presupposes that there is something in need of an explanation - that is, something which is improbable unless explained. | |
From: Howard Robinson (Perception [1994], IX.3) | |
A reaction: Elementary enough, but it underlines the human perspective of all explanations. I may need an explanation of baseball, where you don't. |
6517 | If all possibilities are equal, order seems (a priori) to need an explanation - or does it? [Robinson,H] |
Full Idea: The fact that order requires an explanation seems to be an a priori principle; ..we assume all possibilities are equally likely, and so no striking regularities should emerge; the sceptic replies that a highly ordered sequence is as likely as any other. | |
From: Howard Robinson (Perception [1994], IX.3) | |
A reaction: An independent notion of 'order' is required. If I write down '14356', and then throw 1 4 3 5 6 on a die, the match is the order; instrinsically 14356 is nothing special. If you threw the die a million times, a run of six sixes seems quite likely. |
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. |
6481 | If intentional states are intrinsically about other things, what are their own properties? [Robinson,H] |
Full Idea: Intentional states are mysterious things; if they are intrinsically about other things, what properties, if any, do they possess intrinsically? | |
From: Howard Robinson (Perception [1994], 1.1) | |
A reaction: A very nice question, which I suspect to be right at the heart of the tendency towards externalist accounts of the mind. Since you can only talk about the contents of the thoughts, you can't put forward a decent internalist account of what is going on. |
6503 | Physicalism cannot allow internal intentional objects, as brain states can't be 'about' anything [Robinson,H] |
Full Idea: It is generally conceded by reductive physicalists that a state of the brain cannot be intrinsically about anything, for intentionality is not an intrinsic property of anything, so there can be no internal objects for a physicalist. | |
From: Howard Robinson (Perception [1994], V.4) | |
A reaction: Perhaps it is best to say that 'aboutness' is not a property of physics. We may say that a brain state 'represents' something, because the something caused the brain state, but representations have to be recognised |
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. |
6519 | Locke's solidity is not matter, because that is impenetrability and hardness combined [Robinson,H] |
Full Idea: Notoriously, Locke's filler for Descartes's geometrical matter, solidity, will not do, for that quality collapses on examination into a composite of the dispositional-cum-relational propery of impenetrability, and the secondary quality of hardness. | |
From: Howard Robinson (Perception [1994], IX.3) | |
A reaction: I would have thought the problem was that 'matter is solidity' turns out on analysis to be a tautology. We have a handful of nearly synonymous words for matter and our experiences of it, but they boil down to some 'given' thing for which we lack words. |