28 ideas
| 13445 | Descartes showed a one-one order-preserving match between points on a line and the real numbers [Descartes, by Hart,WD] |
| Full Idea: Descartes founded analytic geometry on the assumption that there is a one-one order-preserving correspondence between the points on a line and the real numbers. | |
| From: report of René Descartes (works [1643]) by William D. Hart - The Evolution of Logic 1 |
| 8568 | A property is merely a constituent of laws of nature; temperature is just part of thermodynamics [Mellor] |
| Full Idea: Being a constituent of probabilistic laws of nature is all there is to being a property. There is no more to temperature than the thermodynamics and other laws they occur in. | |
| From: D.H. Mellor (Properties and Predicates [1991], 'Props') | |
| A reaction: How could thermodynamics be worked out without a prior concept of temperature? I think it is at least plausible to deny that there are any 'laws' of nature. But even Quine can't deny that some things are too hot to touch. |
| 8780 | Attributes are functions, not objects; this distinguishes 'square of 2' from 'double of 2' [Geach] |
| Full Idea: Attributes should not be thought of as identifiable objects. It is better to follow Frege and compare them to mathematical functions. 'Square of' and 'double of' x are distinct functions, even though they are not distinguishable in thought when x is 2. | |
| From: Peter Geach (Mental Acts: their content and their objects [1957], §11) | |
| A reaction: Attributes are features of the world, of which animals are well aware, and the mathematical model is dubious when dealing with physical properties. The route to arriving at 2 is not the same concept as 2. There are many roads to Rome. |
| 8564 | There is obviously a possible predicate for every property [Mellor] |
| Full Idea: To every property there obviously corresponds a possible predicate applying to all and only those particulars with that property. | |
| From: D.H. Mellor (Properties and Predicates [1991], 'Intro') | |
| A reaction: This doesn't strike me as at all obvious. If nature dictates the properties, there may be vastly more than any human language could cope with. It is daft to say that a property can only exist if humanity can come up with a predicate for it. |
| 8566 | We need universals for causation and laws of nature; the latter give them their identity [Mellor] |
| Full Idea: I take the main reason for believing in contingent universals to be the roles they play in causation and in laws of nature, and those laws are what I take to give those universals their identity. | |
| From: D.H. Mellor (Properties and Predicates [1991], 'Props') | |
| A reaction: He agrees with Armstrong. Sounds a bit circular - laws are built on universals, and universals are identified by laws. It resembles a functionalist account of mental events. I think it is wrong. A different account of laws will be needed... |
| 8565 | If properties were just the meanings of predicates, they couldn't give predicates their meaning [Mellor] |
| Full Idea: One reason for denying that properties just are the meanings of our predicates is that, if they were, they could not give our predicates their meanings. | |
| From: D.H. Mellor (Properties and Predicates [1991], 'Props') | |
| A reaction: Neither way round sounds quite right to me. Predicate nominalism is wrong, but what is meant by a property 'giving' a predicate its meaning? It doesn't seem to allow room for error in our attempts to name the properties. |
| 16774 | Descartes thinks distinguishing substances from aggregates is pointless [Descartes, by Pasnau] |
| Full Idea: Descartes thinks it is a pointless relic of scholastic metaphysics to dispute over the boundaries between substances and mere aggregates. | |
| From: report of René Descartes (works [1643]) by Robert Pasnau - Metaphysical Themes 1274-1671 25.6 | |
| A reaction: This is Pasnau's carefully considered conclusion, with which others may not agree. It presumably captures the attitude of modern science generally to such issues. |
| 11910 | Being 'the same' is meaningless, unless we specify 'the same X' [Geach] |
| Full Idea: "The same" is a fragmentary expression, and has no significance unless we say or mean "the same X", where X represents a general term. ...There is no such thing as being just 'the same'. | |
| From: Peter Geach (Mental Acts: their content and their objects [1957], §16) | |
| A reaction: Geach seems oddly unaware of the perfect identity of Hespherus with Phosphorus. His critics don't spot that he was concerned with identity over time (of 'the same man', who ages). Perry's critique emphasises the type/token distinction. |
| 7400 | Descartes said images can refer to objects without resembling them (as words do) [Descartes, by Tuck] |
| Full Idea: Descartes argued (in 'The World') that just as words refer to objects, but they do not resemble them, in the same way, visual images or other sensory inputs relate to objects without depicting them. | |
| From: report of René Descartes (works [1643]) by Richard Tuck - Hobbes | |
| A reaction: This strikes me as a rather significant and plausible claim, which might contain the germ of the idea of a language of thought. It is also the basis for the recent view that language is the best route to understanding the mind. |
| 8775 | A big flea is a small animal, so 'big' and 'small' cannot be acquired by abstraction [Geach] |
| Full Idea: A big flea or rat is a small animal, and a small elephant is a big animal, so there can be no question of ignoring the kind of thing to which 'big' or 'small' is referred and forming those concepts by abstraction. | |
| From: Peter Geach (Mental Acts: their content and their objects [1957], §9) | |
| A reaction: Geach is attacking a caricature of the theory. Abstraction is a neat mental trick which has developed in stages, from big rats relative to us, to big relative to other rats, to the concept of 'relative' (Idea 8776!), to the concept of 'relative bigness'. |
| 8776 | We cannot learn relations by abstraction, because their converse must be learned too [Geach] |
| Full Idea: Abstractionists are unaware of the difficulty with relations - that they neither exist nor can be observed apart from the converse relation, the two being indivisible, as in grasping 'to the left of' and 'to the right of'. | |
| From: Peter Geach (Mental Acts: their content and their objects [1957], §9) | |
| A reaction: It is hard to see how a rival account such as platonism could help. It seems obvious to me that 'right' and 'left' would be quite meaningless without some experience of things in space, including an orientation to them. |
| 4310 | We have inner awareness of our freedom [Descartes] |
| Full Idea: We have inner awareness of our freedom. | |
| From: René Descartes (works [1643]) | |
| A reaction: This begs a few questions. I may be directly aware that I have not been hypnotised, but no one would accept it as proof. |
| 6553 | Descartes discussed the interaction problem, and compared it with gravity [Descartes, by Lycan] |
| Full Idea: Descartes himself was well aware of the interaction problem, and corresponded uncomfortably with Princess Elizabeth on the matter; …he pointed out that gravity is causal despite not being a physical object. | |
| From: report of René Descartes (works [1643]) by William Lycan - Consciousness n1.3 | |
| A reaction: Lycan observes that at least gravity is in space-time, unlike the Cartesian mind. Pierre Gassendi had pointed out the problem to Descartes in the Fifth Objection to the 'Meditations' (see Idea 3400). |
| 2567 | You can't define real mental states in terms of behaviour that never happens [Geach] |
| Full Idea: We can't take a statement that two men, whose overt behaviour was not actually different, were in different states of mind as being really a statement that the behaviour of one man would have been different in hypothetical circumstances that never arose. | |
| From: Peter Geach (Mental Acts: their content and their objects [1957], §3) | |
| A reaction: This is the whole problem with trying to define the mind as dispositions. The same might be said of properties, since some properties are active, but others are mere potential or disposition. Hence 'process' looks to me the most promising word for mind. |
| 2568 | Beliefs aren't tied to particular behaviours [Geach] |
| Full Idea: Is there any behaviour characteristic of a given belief? | |
| From: Peter Geach (Mental Acts: their content and their objects [1957], §4) | |
| A reaction: Well, yes. Belief that a dog is about to bite you. Belief that this nice food is yours, and you are hungry. But he has a good point. He is pointing out that the mental state is a very different thing from the 'disposition' to behave in a certain way. |
| 8781 | The mind does not lift concepts from experience; it creates them, and then applies them [Geach] |
| Full Idea: Having a concept is not recognizing a feature of experience; the mind makes concepts. We then fit our concepts to experience. | |
| From: Peter Geach (Mental Acts: their content and their objects [1957], §11) | |
| A reaction: This seems to imply that we create concepts ex nihilo, which is a rather worse theory than saying that we abstract them from multiple (and multi-level) experiences. That minds create concepts is a truism. How do we do it? |
| 8769 | If someone has aphasia but can still play chess, they clearly have concepts [Geach] |
| Full Idea: If a man struck with aphasia can still play bridge or chess, I certainly wish to say he still has the concepts involved in the game, although he can no longer exercise them verbally. | |
| From: Peter Geach (Mental Acts: their content and their objects [1957], §5) | |
| A reaction: Geach proceeds thereafter to concentrate on language, but this caveat is crucial. To suggest that concepts are entirely verbal has always struck me as ridiculous, and an insult to our inarticulate mammalian cousins. |
| 8770 | 'Abstractionism' is acquiring a concept by picking out one experience amongst a group [Geach] |
| Full Idea: I call 'abstractionism' the doctrine that a concept is acquired by a process of singling out in attention some one feature given in direct experience - abstracting it - and ignoring the other features simultaneously given - abstracting from them. | |
| From: Peter Geach (Mental Acts: their content and their objects [1957], §6) | |
| A reaction: Locke seems to be the best known ancestor of this view, and Geach launches a vigorous attack against it. However, contemporary philosophers still refer to the process, and I think Geach should be crushed and this theory revived. |
| 8771 | 'Or' and 'not' are not to be found in the sensible world, or even in the world of inner experience [Geach] |
| Full Idea: Nowhere in the sensible world could you find anything to be suitably labelled 'or' or 'not'. So the abstractionist appeals to an 'inner sense', or hesitation for 'or', and of frustration or inhibition for 'not'. Personally I see a threat in 'or else'! | |
| From: Peter Geach (Mental Acts: their content and their objects [1957], §7) | |
| A reaction: This is a key argument of Geach's against abstractionism. As a logician he prefers to discuss connectives rather than, say, colours. I think they might be meta-abstractions, which you create internally once you have picked up the knack. |
| 8772 | We can't acquire number-concepts by extracting the number from the things being counted [Geach] |
| Full Idea: The number-concepts just cannot be got by concentrating on the number and abstracting from the kind of things being counted. | |
| From: Peter Geach (Mental Acts: their content and their objects [1957], §8) | |
| A reaction: This point is from Frege - that if you 'abstract away' everything apart from the number, you are simply left with nothing in experience. The objection might, I think, be met by viewing it as second-order abstraction, perhaps getting to a pattern first. |
| 8773 | Abstractionists can't explain counting, because it must precede experience of objects [Geach] |
| Full Idea: The way counting is learned is wholly contrary to abstractionist preconceptions, because the series of numerals has to be learned before it can be applied. | |
| From: Peter Geach (Mental Acts: their content and their objects [1957], §8) | |
| A reaction: You might learn to parrot the names of numbers, but you could hardly know what they meant if you couldn't count anything. See Idea 3907. I would have thought that individuating objects must logically and pedagogically precede counting. |
| 8774 | The numbers don't exist in nature, so they cannot have been abstracted from there into our languages [Geach] |
| Full Idea: The pattern of the numeral series that is grasped by a child exists nowhere in nature outside human languages, so the human race cannot possibly have discerned this pattern by abstracting it from some natural context. | |
| From: Peter Geach (Mental Acts: their content and their objects [1957], §8) | |
| A reaction: This is a spectacular non sequitur, which begs the question. Abstractionists precisely claim that the process of abstraction brings numerals into human language from the natural context. Structuralism is an attempt to explain the process. |
| 8778 | Blind people can use colour words like 'red' perfectly intelligently [Geach] |
| Full Idea: It is not true that men born blind can form no colour-concepts; a man born blind can use the word 'red' with a considerable measure of intelligence; he can show a practical grasp of the logic of the word. | |
| From: Peter Geach (Mental Acts: their content and their objects [1957], §10) | |
| A reaction: Weak. It is obvious that they pick up the word 'red' from the usage of sighted people, and the usage of the word doesn't guarantee a grasp of the concept, as when non-mathematicians refer to 'calculus'. Compare Idea 7377 and Idea 7866. |
| 8777 | If 'black' and 'cat' can be used in the absence of such objects, how can such usage be abstracted? [Geach] |
| Full Idea: Since we can use the terms 'black' and 'cat' in situations not including any black object or any cat, how could this part of the use be got by abstraction? | |
| From: Peter Geach (Mental Acts: their content and their objects [1957], §10) | |
| A reaction: [He is attacking H.H. Price] It doesn't seem a huge psychological leap to apply the word 'cat' when we remember a cat, and once it is in the mind we can play games with our abstractions. Cats are smaller than dogs. |
| 8779 | We can form two different abstract concepts that apply to a single unified experience [Geach] |
| Full Idea: It is impossible to form the concept of 'chromatic colour' by discriminative attention to a feature given in my visual experience. In seeing a red window-pane, I do not have two sensations, one of redness and one of chromatic colour. | |
| From: Peter Geach (Mental Acts: their content and their objects [1957], §10) | |
| A reaction: Again Geach begs the question, because abstractionists claim that you can focus on two different 'aspects' of the one experience, as that it is a 'window', or it is 'red', or it is not a wall, or it is not monochrome. |
| 19676 | Nature is devoid of thought [Descartes, by Meillassoux] |
| Full Idea: It is Descartes who ratifies the idea that nature is devoid of thought. | |
| From: report of René Descartes (works [1643]) by Quentin Meillassoux - After Finitude; the necessity of contingency 5 | |
| A reaction: His dualism is crucial, along with his ontological argument, because they make all mentality supernatural. Remember, for Descartes animals are mindless machines. |
| 6518 | Matter can't just be Descartes's geometry, because a filler of the spaces is needed [Robinson,H on Descartes] |
| Full Idea: Notoriously, the Cartesian idea that matter is purely geometrical will not do, for it leaves no distinction between matter and empty volumes: a filler for these volumes is required. | |
| From: comment on René Descartes (works [1643]) by Howard Robinson - Perception IX.3 | |
| A reaction: Descartes thinks of matter as 'extension'. Descartes's error seems so obvious that it is a puzzle why he made it. He may have confused epistemology and ontology - all we can know of matter is its extension in space. |
| 8567 | Singular causation requires causes to raise the physical probability of their effects [Mellor] |
| Full Idea: Singular causation entails physical probabilities or chances. ...Causal laws require causes to raise their effects' chances, as when fires have a greater chance of occurring when explosions do. | |
| From: D.H. Mellor (Properties and Predicates [1991], 'Props') | |
| A reaction: It seems fairly obvious that a probability can be increased without actually causing something. Just after a harmless explosion is a good moment for arsonists, especially if Mellor will be the investigating officer. |