26 ideas
| 14238 | A class is an aggregate of objects; if you destroy them, you destroy the class; there is no empty class [Frege] |
| Full Idea: A class consists of objects; it is an aggregate, a collective unity, of them; if so, it must vanish when these objects vanish. If we burn down all the trees of a wood, we thereby burn down the wood. Thus there can be no empty class. | |
| From: Gottlob Frege (Elucidation of some points in E.Schröder [1895], p.212), quoted by Oliver,A/Smiley,T - What are Sets and What are they For? | |
| A reaction: This rests on Cantor's view of a set as a collection, rather than on Dedekind, which allows null and singleton sets. |
| 6472 | Continuity is a sufficient criterion for the identity of a rock, but not for part of a smooth fluid [Russell] |
| Full Idea: Continuity is not a sufficient criterion of material identity; it is sufficient in many cases, such as rocks and tables, where the appearances change slowly, but in others, such as the parts of an approximately homogeneous fluid, it fails us utterly. | |
| From: Bertrand Russell (The Relation of Sense-Data to Physics [1914], §XI) | |
| A reaction: It might be debatable to what extent the 'parts' of a homogeneous fluid have identity. How many 'parts' are there in a glass of water? This seems, now, a problem for internalists; externalists can define the identity by the unseen molecules. |
| 6473 | Physical things are series of appearances whose matter obeys physical laws [Russell] |
| Full Idea: We may lay down the following definition: Physical things are those series of appearances whose matter obeys the laws of physics. | |
| From: Bertrand Russell (The Relation of Sense-Data to Physics [1914], §XI) | |
| A reaction: We will then have to define the laws of physic without making any reference to 'physical things'. There is an obvious suspicion of circularity somewhere here. I find it very odd to define objects just in terms of their appearances. |
| 6465 | We need not deny substance, but there seems no reason to assert it [Russell] |
| Full Idea: It is not necessary to deny a substance or substratum underlying appearances; it is merely expedient (by the application of Occam's Razor) to abstain from asserting this unnecessary entity. | |
| From: Bertrand Russell (The Relation of Sense-Data to Physics [1914], §V) | |
| A reaction: Russell then goes on to struggle heroically in attempts to give accounts of 'matter' and 'objects' entirely in terms of 'sense-data'. If he failed, as many think he did, should we go back to belief in Aristotelian substance? |
| 6471 | The assumption by physicists of permanent substance is not metaphysically legitimate [Russell] |
| Full Idea: The assumption of permanent substance, which technically underlies the procedure of physics, cannot of course be regarded as metaphysically legitimate. | |
| From: Bertrand Russell (The Relation of Sense-Data to Physics [1914], §XI) | |
| A reaction: It is a moot point whether physicists still thought this way after the full arrival of quantum theory in 1926. Russell raises all sorts of nice questions about the relationship between physics and philosophy here. I'm on Russell's side. |
| 8361 | What is true used to be possible, but it may no longer be so [Wright,GHv] |
| Full Idea: It is not very natural to say of that which is true that it is also possible. ...What is true was possible - but whether it still is a potency of the world is not certain. | |
| From: G.H. von Wright (Logic and Epistemology of Causal Relations [1973], §5) | |
| A reaction: A simple and rather important distinction. Before encountering this, I would certainly have been happy to affirm that the actual is possible, but actually it may not be. The power to create differs from the power to sustain. Could God re-create the world? |
| 6466 | Where possible, logical constructions are to be substituted for inferred entities [Russell] |
| Full Idea: The supreme maxim in scientific philosophising is this: Wherever possible, logical constructions are to be substituted for inferred entities. | |
| From: Bertrand Russell (The Relation of Sense-Data to Physics [1914], §VI) | |
| A reaction: This seems to represent Russell's first move (in 1914) into what looks like phenomenalism. One might ask what is the difference between 'logical constructions' and 'inferred entities'. The latter appear to have unity, so I prefer them. |
| 6467 | No sensibile is ever a datum to two people at once [Russell] |
| Full Idea: No sensibile is ever a datum to two people at once. | |
| From: Bertrand Russell (The Relation of Sense-Data to Physics [1914], §VII) | |
| A reaction: So a loud bang has to broken down into an almost infinite number of sound sensibilia - each one presumably the size of the apperture of a small ear. This is beginning to sound a bit silly. |
| 6483 | Russell held that we are aware of states of our own brain [Russell, by Robinson,H] |
| Full Idea: Russell held that we are aware of states of our own brain. | |
| From: report of Bertrand Russell (The Relation of Sense-Data to Physics [1914]) by Howard Robinson - Perception 1.1 | |
| A reaction: I can't say that I had ever intepreted Russell in this way, but it is a wonderfully thought-provoking idea. All the time that I thought I was looking at a table, I was just looking at my own brain, and drawing an unspoken inference that a table caused it. |
| 8244 | Sense-data are qualities devoid of subjectivity, which are the basis of science [Russell, by Deleuze/Guattari] |
| Full Idea: Rather than oppose sensory knowledge and scientific knowledge, we should identify the sensibilia that are peculiar to science. This is what Russell did when he evoked sense-data, qualities devoid of all subjectivity. | |
| From: report of Bertrand Russell (The Relation of Sense-Data to Physics [1914]) by G Deleuze / F Guattari - What is Philosophy? 2.5 | |
| A reaction: An interesting observation. Russell is striking for his lack of interest in theories of arts and ethics, and his whole work focuses on understanding the scientific view. What is involved in sensibilia is a key modern issue (e.g. McDowell). |
| 6462 | Sense-data are not mental, but are part of the subject-matter of physics [Russell] |
| Full Idea: I regard sense-data as not mental, and as being, in fact, part of the actual subject-matter of physics. | |
| From: Bertrand Russell (The Relation of Sense-Data to Physics [1914], §III) | |
| A reaction: Russell had clearly given himself an ontological problem with the introduction of sense-data, and this is his drastic solution. In 1912 his account seems ambiguous between sense-data being mental and being physical. |
| 6463 | Sense-data are objects, and do not contain the subject as part, the way beliefs do [Russell] |
| Full Idea: Logically a sense-datum is an object, a particular of which the subject is aware; it does not contain the subject as a part, as for example beliefs and volitions do. | |
| From: Bertrand Russell (The Relation of Sense-Data to Physics [1914], §IV) | |
| A reaction: This very firmly rejects any notion that a sense-datum is mental. It is a left as a strange sort of object which gets as close as it is possible to get to the 'borders' of the mind, without actually becoming part of it. |
| 6464 | Sense-data are usually objects within the body, but are not part of the subject [Russell] |
| Full Idea: The sense-datum is an external object of which in sensation the subject is aware; it is true that the sense-datum is in many cases in the subject's body, but the subject's body is as distinct from the subject as tables and chairs are. | |
| From: Bertrand Russell (The Relation of Sense-Data to Physics [1914], §IV) | |
| A reaction: This is probably Russell's clearest statement of the nature of sense-data, which are objects within the subjects body, but are not part of the mind. So once again we come up against the question of their ontology. Are they made of neurons? |
| 6459 | We do not know whether sense-data exist as objects when they are not data [Russell] |
| Full Idea: We do not know, except by means of more or less precarious inferences, whether the objects which are at one time sense-data continue to exist at times when they are not data. | |
| From: Bertrand Russell (The Relation of Sense-Data to Physics [1914], §II) | |
| A reaction: Note that he actually refers to sense-data as 'objects'. It shows how thoroughly reified they are in his theory if they have the possibility of independent existence. This invites the question 'what are they made of?' |
| 6460 | 'Sensibilia' are identical to sense-data, without actually being data for any mind [Russell] |
| Full Idea: I shall give the name 'sensibilia' to those objects which have the same metaphysical and physical status as sense-data without necessarily being data to any mind. | |
| From: Bertrand Russell (The Relation of Sense-Data to Physics [1914], §III) | |
| A reaction: This is his response to the problem of whether sense-data can exist independently of experience, which was unclear in 1912. Presumably sensibilia are objects which are possible sources of experience, but that seems to cover most objects. |
| 6461 | Ungiven sense-data can no more exist than unmarried husbands [Russell] |
| Full Idea: We cannot ask, 'Can sense-data exist without being given?' for that is like asking, 'Can husbands exist without being married?' | |
| From: Bertrand Russell (The Relation of Sense-Data to Physics [1914], §III) | |
| A reaction: This follows hard on Idea 6460, which introduces the idea of 'sensibilia' for things which are like sense-data, but are not 'given'. This is a new distinction in 1914, which he had not made in 1912. |
| 6458 | Individuating sense-data is difficult, because they divide when closely attended to [Russell] |
| Full Idea: There is some difficulty in deciding what is to be considered one sense-datum: often attention causes divisions to appear where, so far as can be discovered, there were no divisions before. | |
| From: Bertrand Russell (The Relation of Sense-Data to Physics [1914], §II) | |
| A reaction: This was, I suspect, why Russell had dropped the idea of sense-data by 1921. He does, however, say that they are the last unit in analysis, rather than being the most basic unit of perception. In other words, they are purely theoretical. |
| 6469 | Sense-data may be subjective, if closing our eyes can change them [Russell] |
| Full Idea: One reason often alleged for the subjectivity of sense-data is that the appearance of a thing itself may change when we find it hard to suppose that the thing itself has changed - as when we shut our eyes, or screw them up to make things look double. | |
| From: Bertrand Russell (The Relation of Sense-Data to Physics [1914], §VIII) | |
| A reaction: Russell firmly denies that they are subjective. These examples are also said to support to proposed existence of sense-data in the first place, since they show the gap between appearance and reality. |
| 8363 | p is a cause and q an effect (not vice versa) if manipulations of p change q [Wright,GHv] |
| Full Idea: What makes p a cause-factor relative to the effect-factor q (rather than vice versa) is the fact that by manipulating p, producing changes in it 'at will', we could bring about changes in q. | |
| From: G.H. von Wright (Logic and Epistemology of Causal Relations [1973], §8) | |
| A reaction: As a solution to the direction-of-causation problem, I suspect that this proposal is begging the question. Will a causal explanation be offered of the action of manipulation? If he mistook his manipulation for a cause when it is actually an effect... |
| 8364 | We can imagine controlling floods by controlling rain, but not vice versa [Wright,GHv] |
| Full Idea: Given our present knowledge of the laws of nature, we can imagine ways of controlling floods by controlling rainfall, but not the other way round. That is should be so, however, is contingent. | |
| From: G.H. von Wright (Logic and Epistemology of Causal Relations [1973], §8) | |
| A reaction: Despite my objections to Idea 8363, this is a good example. It won't establish the metaphysics of the direction of causation, though, because God might control rainfall by controlling floods. Maybe causation is more like a motorway pile-up than dominoes. |
| 8366 | The very notion of a cause depends on agency and action [Wright,GHv] |
| Full Idea: There is an implicit dependence of the very notion of a cause on a concept of agency and action. | |
| From: G.H. von Wright (Logic and Epistemology of Causal Relations [1973], §10) | |
| A reaction: This is because he thinks experimental intervention is the key to the concept of causation (see Ideas 8362 and 8363). Others go further, and say that the concept of causation arises from subjective experience of performing actions. I quite like that. |
| 8362 | We give regularities a causal character by subjecting them to experiment [Wright,GHv] |
| Full Idea: What confers on observed regularities the character of causal or nomic connections is the possibility of subjecting cause-factors to experimental test by interfering with the 'natural' course of events. | |
| From: G.H. von Wright (Logic and Epistemology of Causal Relations [1973], §7) | |
| A reaction: This is von Wright's distinctive proposal, making causation a feature of the culture of science, rather than of ordinary life. But see Idea 2461. Causation is becoming too epistemological for my taste. Either it is a feature of reality, or forget it. |
| 8360 | We must further analyse conditions for causation, into quantifiers or modal concepts [Wright,GHv] |
| Full Idea: We may be able to analyse causation into conditionship relations between events or states of affairs, ...but conditions cannot be regarded as logical primitives, ... and must be analysed into quantifiers, or modal concepts. | |
| From: G.H. von Wright (Logic and Epistemology of Causal Relations [1973], §2) | |
| A reaction: [very compressed] A nice illustration of the aim of analytical philosophy - to analyse the elements of reality down to logical primitives. This is the dream of Descartes and Leibniz, continued by Russell and co. Do we still have this aspiration? |
| 8365 | Some laws are causal (Ohm's Law), but others are conceptual principles (conservation of energy) [Wright,GHv] |
| Full Idea: Not all laws are causal 'experimentalist' laws, such as those for falling bodies, or the Gas Law, or Ohm's Law. Some are more like conceptual principles, giving a frame of reference, such as inertia, or conservation of energy, or the law of entropy. | |
| From: G.H. von Wright (Logic and Epistemology of Causal Relations [1973], §9) | |
| A reaction: An interesting and important distinction, whenever one is exploring the links between theories of causation and of laws of nature. If one wished to attack the whole concept of 'laws of nature', this might be a good place to start. |
| 6470 | Matter is the limit of appearances as distance from the object diminishes [Russell] |
| Full Idea: We offer the following tentative definition: The matter of a given thing is the limit of its appearances as their distance from the thing diminishes. | |
| From: Bertrand Russell (The Relation of Sense-Data to Physics [1914], §IX) | |
| A reaction: This strikes me as empiricism gone mad. Russell is famous for being a 'realist', but you would hardly know it at this point. Personally I put emphasis on 'best explanation', which fairly simply delivers most of our commonsense understandings of reality. |
| 6468 | There is 'private space', and there is also the 'space of perspectives' [Russell] |
| Full Idea: In addition to the private spaces, ..there is the 'space of perspectives', since each private world may be regarded as the appearance which the universe presents from a certain point of view. | |
| From: Bertrand Russell (The Relation of Sense-Data to Physics [1914], §VII) | |
| A reaction: This replaces his concept of 'public space', which he introduced in 1912. Russell gradually dropped this, but I like the idea that we somehow directly perceive space in two ways simultaneously (which led him to say that space is six-dimensional). |