48 ideas
6420 | Only by analysing is progress possible in philosophy [Russell] |
Full Idea: I remain firmly persuaded, in spite of some modern tendencies to the contrary, that only by analysing is progress possible, …for example, by analysing physics and perception, the problem of mind and matter can be completely solved. | |
From: Bertrand Russell (My Philosophical Development [1959], Ch.1) | |
A reaction: I don't share his confidence in the second part of this, but I subscribe to the maxim that 'analsis is the path to wisdom'. It is a very western view, and lots of people (mostly of a mystical disposition) hate it, but I see no better path. |
6432 | Analysis gives new knowledge, without destroying what we already have [Russell] |
Full Idea: It seems to me evident that, as in the case of impure water, analysis gives new knowledge without destroying any of the previously existing knowledge. | |
From: Bertrand Russell (My Philosophical Development [1959], Ch.11) | |
A reaction: I agree. On the whole, opponents of analysis are sentimental mystics who are reluctant to think carefully about life. I'm not sure what careful and concentrated thought is capable of, apart from analysis. |
18781 | Inconsistency doesn't prevent us reasoning about some system [Mares] |
Full Idea: We are able to reason about inconsistent beliefs, stories, and theories in useful and important ways | |
From: Edwin D. Mares (Negation [2014], 1) |
6437 | The theory of types makes 'Socrates and killing are two' illegitimate [Russell] |
Full Idea: 'Socrates and killing are two' would be an illegitimate sentence according to the doctrine of types. | |
From: Bertrand Russell (My Philosophical Development [1959], Ch.14) | |
A reaction: This nicely shows how Ryle's notion of a 'category mistake', although it is a commonsense observation of bogus reasoning, arises out of Russell's logical analysis of sets. Of course, the theory of types has its critics. |
6442 | Truth belongs to beliefs, not to propositions and sentences [Russell] |
Full Idea: Truth and falsehood both belong primarily to beliefs, and only derivatively to propositions and sentences. | |
From: Bertrand Russell (My Philosophical Development [1959], Ch.15) | |
A reaction: I'm not sure why a proposition which is date/place stamped ('it is raining, here and now') could not be considered a truth, even if no one believed it. Is not the proposition 'squares have four sides' true? |
18790 | Intuitionism as natural deduction has no rule for negation [Mares] |
Full Idea: In intuitionist logic each connective has one introduction and one elimination rule attached to it, but in the classical system we have to add an extra rule for negation. | |
From: Edwin D. Mares (Negation [2014], 5.5) | |
A reaction: How very intriguing. Mares says there are other ways to achieve classical logic, but they all seem rather cumbersome. |
18789 | Intuitionist logic looks best as natural deduction [Mares] |
Full Idea: Intuitionist logic appears most attractive in the form of a natural deduction system. | |
From: Edwin D. Mares (Negation [2014], 5.5) |
18787 | Three-valued logic is useful for a theory of presupposition [Mares] |
Full Idea: One reason for wanting a three-valued logic is to act as a basis of a theory of presupposition. | |
From: Edwin D. Mares (Negation [2014], 3.1) | |
A reaction: [He cites Strawson 1950] The point is that you can get a result when the presupposition does not apply, as in talk of the 'present King of France'. |
6436 | I gradually replaced classes with properties, and they ended as a symbolic convenience [Russell] |
Full Idea: My original use of classes was gradually more and more replaced by properties, and in the end disappeared except as a symbolic convenience. | |
From: Bertrand Russell (My Philosophical Development [1959], Ch.14) | |
A reaction: I wish I knew what properties are. On the whole, though, I agree with this, because it is more naturalistic. We may place things in classes because of their properties, and this means there are natural classes, but classes can't have a life of their own. |
18793 | Material implication (and classical logic) considers nothing but truth values for implications [Mares] |
Full Idea: The problem with material implication, and classical logic more generally, is that it considers only the truth value of formulas in deciding whether to make an implication stand between them. It ignores everything else. | |
From: Edwin D. Mares (Negation [2014], 7.1) | |
A reaction: The obvious problem case is conditionals, and relevance is an obvious extra principle that comes to mind. |
18784 | In classical logic the connectives can be related elegantly, as in De Morgan's laws [Mares] |
Full Idea: Among the virtues of classical logic is the fact that the connectives are related to one another in elegant ways that often involved negation. For example, De Morgan's Laws, which involve negation, disjunction and conjunction. | |
From: Edwin D. Mares (Negation [2014], 2.2) | |
A reaction: Mares says these enable us to take disjunction or conjunction as primitive, and then define one in terms of the other, using negation as the tool. |
18786 | Excluded middle standardly implies bivalence; attacks use non-contradiction, De M 3, or double negation [Mares] |
Full Idea: On its standard reading, excluded middle tells us that bivalence holds. To reject excluded middle, we must reject either non-contradiction, or ¬(A∧B) ↔ (¬A∨¬B) [De Morgan 3], or the principle of double negation. All have been tried. | |
From: Edwin D. Mares (Negation [2014], 2.2) |
18780 | Standard disjunction and negation force us to accept the principle of bivalence [Mares] |
Full Idea: If we treat disjunction in the standard way and take the negation of a statement A to mean that A is false, accepting excluded middle forces us also to accept the principle of bivalence, which is the dictum that every statement is either true or false. | |
From: Edwin D. Mares (Negation [2014], 1) | |
A reaction: Mates's point is to show that passively taking the normal account of negation for granted has important implications. |
7528 | Leibniz bases everything on subject/predicate and substance/property propositions [Russell] |
Full Idea: The metaphysics of Leibniz was explicitly based upon the doctrine that every proposition attributes a predicate to a subject and (what seemed to him almost the same thing) that every fact consists of a substance having a property. | |
From: Bertrand Russell (My Philosophical Development [1959], Ch.5) | |
A reaction: I think it is realised now that although predicates tend to attribute properties to things, they are far from being the same thing. See Idea 4587, for example. Russell gives us an interesting foot in the door of Leibniz's complex system. |
18782 | The connectives are studied either through model theory or through proof theory [Mares] |
Full Idea: In studying the logical connectives, philosophers of logic typically adopt the perspective of either model theory (givng truth conditions of various parts of the language), or of proof theory (where use in a proof system gives the connective's meaning). | |
From: Edwin D. Mares (Negation [2014], 1) | |
A reaction: [compressed] The commonest proof theory is natural deduction, giving rules for introduction and elimination. Mates suggests moving between the two views is illuminating. |
6439 | Names are meaningless unless there is an object which they designate [Russell] |
Full Idea: Unlike descriptions, names are meaningless unless there is an object which they designate. | |
From: Bertrand Russell (My Philosophical Development [1959], Ch.14) | |
A reaction: This interests Russell because of its ontological implications. If we reduce language to names, we can have a pure ontology of 'objects'. We need a system for saying whether a description names something - which is his theory of definite descriptions. |
18783 | Many-valued logics lack a natural deduction system [Mares] |
Full Idea: Many-valued logics do not have reasonable natural deduction systems. | |
From: Edwin D. Mares (Negation [2014], 1) |
18792 | Situation semantics for logics: not possible worlds, but information in situations [Mares] |
Full Idea: Situation semantics for logics consider not what is true in worlds, but what information is contained in situations. | |
From: Edwin D. Mares (Negation [2014], 6.2) | |
A reaction: Since many theoretical physicists seem to think that 'information' might be the most basic concept of a natural ontology, this proposal is obviously rather appealing. Barwise and Perry are the authors of the theory. |
18785 | Consistency is semantic, but non-contradiction is syntactic [Mares] |
Full Idea: The difference between the principle of consistency and the principle of non-contradiction is that the former must be stated in a semantic metalanguage, whereas the latter is a thesis of logical systems. | |
From: Edwin D. Mares (Negation [2014], 2.2) |
6423 | We tried to define all of pure maths using logical premisses and concepts [Russell] |
Full Idea: The primary aim of our 'Principia Mathematica' was to show that all pure mathematics follows from purely logical premisses and uses only concepts definable in logical terms. | |
From: Bertrand Russell (My Philosophical Development [1959], Ch.7) | |
A reaction: This spells out the main programme of logicism, by its great hero, Russell. The big question now is whether Gödel's Incompleteness Theorems have succeeded in disproving logicism. |
6425 | Formalism can't apply numbers to reality, so it is an evasion [Russell] |
Full Idea: Formalism is perfectly adequate for doing sums, but not for the application of number, such as the simple statement 'there are three men in this room', so it must be regarded as an unsatisfactory evasion. | |
From: Bertrand Russell (My Philosophical Development [1959], Ch.10) | |
A reaction: This seems to me a powerful and simple objection. The foundation of arithmetic is that there are three men in the room, not that one plus two is three. Three men and three ties make a pattern, which we call 'three'. |
6424 | Formalists say maths is merely conventional marks on paper, like the arbitrary rules of chess [Russell] |
Full Idea: The Formalists, led by Hilbert, maintain that arithmetic symbols are merely marks on paper, devoid of meaning, and that arithmetic consists of certain arbitrary rules, like the rules of chess, by which these marks can be manipulated. | |
From: Bertrand Russell (My Philosophical Development [1959], Ch.10) | |
A reaction: I just don't believe that maths is arbitrary, and this view pushes me into the arms of the empiricists, who say maths is far more likely to arise from experience than from arbitrary convention. The key to maths is patterns. |
6426 | Intuitionism says propositions are only true or false if there is a method of showing it [Russell] |
Full Idea: The nerve of the Intuitionist theory, led by Brouwer, is the denial of the law of excluded middle; it holds that a proposition can only be accounted true or false when there is some method of ascertaining which of these it is. | |
From: Bertrand Russell (My Philosophical Development [1959], Ch.2) | |
A reaction: He cites 'there are three successive sevens in the expansion of pi' as a case in point. This seems to me an example of the verificationism and anti-realism which is typical of that period. It strikes me as nonsense, but Russell takes it seriously. |
18788 | For intuitionists there are not numbers and sets, but processes of counting and collecting [Mares] |
Full Idea: For the intuitionist, talk of mathematical objects is rather misleading. For them, there really isn't anything that we should call the natural numbers, but instead there is counting. What intuitionists study are processes, such as counting and collecting. | |
From: Edwin D. Mares (Negation [2014], 5.1) | |
A reaction: That is the first time I have seen mathematical intuitionism described in a way that made it seem attractive. One might compare it to a metaphysics based on processes. Apparently intuitionists struggle with infinite sets and real numbers. |
22227 | For Sartre there is only being for-itself, or being in-itself (which is beyond experience) [Sartre, by Daigle] |
Full Idea: The two most fundamental modes of being in Sartre's ontology are being in-itself, and being for-itself. ...The in-itself lies beyond our experience of it. | |
From: report of Jean-Paul Sartre (Being and Nothingness [1943]) by Christine Daigle - Jean-Paul Sartre 2.2 | |
A reaction: This appears to be Kant's ding-an-sich, paired with Heidegger's Dasein. If those are the only options, then reality is either subjective or unknown, which seems to make Sartre an idealist, but he asserted that phenomena vindicate the in-itself. |
6419 | In 1899-1900 I adopted the philosophy of logical atomism [Russell] |
Full Idea: In the years 1899-1900 I adopted the philosophy of logical atomism. | |
From: Bertrand Russell (My Philosophical Development [1959], Ch.1) | |
A reaction: This is interesting (about Russell) because he only labelled it as 'logical atomism' in about 1912, and only wrote about it as such in 1918. It is helpful to understand that the theory of definite descriptions was part of his logical atomism. |
6438 | Complex things can be known, but not simple things [Russell] |
Full Idea: I have come to think that, although many things can be known to be complex, nothing can be known to be simple. | |
From: Bertrand Russell (My Philosophical Development [1959], Ch.14) | |
A reaction: This appears to be a rejection of his logical atomism. It goes with a general rebellion against foundationalist epistemology, because the empiricists foundations (e.g. Hume's impressions) seem devoid of all content. |
6434 | Facts are everything, except simples; they are either relations or qualities [Russell] |
Full Idea: Facts, as I am using the word, consist always of relations between parts of a whole or qualities of single things; facts, in a word, are whatever there is except what (if anything) is completely simple. | |
From: Bertrand Russell (My Philosophical Development [1959], Ch.13) | |
A reaction: This is the view that goes with Russell's 'logical atomism', where the 'completely simple' is used to build up the 'facts'. If World War One was a fact, was it a 'relation' or a 'quality'. Must events then be defined in terms of those two? |
6440 | Universals can't just be words, because words themselves are universals [Russell] |
Full Idea: Those who dislike universals have thought that they could be merely words; the trouble with this view is that a word itself is a universal. | |
From: Bertrand Russell (My Philosophical Development [1959], Ch.14) | |
A reaction: Russell gradually lost his faith in most things, but never in universals. I find it unconvincing that we might dismiss nominalism so easily. I'm not sure why the application of the word 'cat' could not just be conventional. |
6430 | In epistemology we should emphasis the continuity between animal and human minds [Russell] |
Full Idea: It seems to me desirable in the theory of knowledge to emphasise the continuity between animal and human minds. | |
From: Bertrand Russell (My Philosophical Development [1959], Ch.11) | |
A reaction: I strongly agree with this, mainly because it avoids overemphasis on language in epistemology. It doesn't follow that animals know a lot, and there is a good case for saying that they don't actually 'know' anything, despite having true beliefs. |
20743 | Appearances do not hide the essence; appearances are the essence [Sartre] |
Full Idea: We reject the dualism of appearance and essence. The appearance does not hide the essence, it reveals it; it is the essence. | |
From: Jean-Paul Sartre (Being and Nothingness [1943], p.4-5), quoted by Kevin Aho - Existentialism: an introduction 2 'Phenomenology' | |
A reaction: This idea, expressed in the language of Hegel and Husserl, strikes me as the same as the analytic phenomenalism of Mill and Ayer. Hence I take it to be wrong. |
6441 | Pragmatism judges by effects, but I judge truth by causes [Russell] |
Full Idea: Pragmatism holds that a belief is to be judged if it has certain effects, whereas I hold that an empirical belief is to be judged true if it has certain kinds of causes. | |
From: Bertrand Russell (My Philosophical Development [1959], Ch.15) | |
A reaction: I'm with Russell here, and this seems to me a convincing objection to pragmatism. The simple problem is that falsehoods can occasionally have very beneficial effects. Beliefs are made true by the facts, not by their consequences. |
6431 | Empiricists seem unclear what they mean by 'experience' [Russell] |
Full Idea: When I began to think about theory of knowledge, I found that none of the philosophers who emphasise 'experience' tells us what they mean by the word. | |
From: Bertrand Russell (My Philosophical Development [1959], Ch.11) | |
A reaction: A very significant comment about empiricism. Hume does not seem very clear about what an 'impression' is. Russell's problem has been dealt with intensively by modern empiricists, who discuss 'the given', and conceptualised perception. |
6444 | True belief about the time is not knowledge if I luckily observe a stopped clock at the right moment [Russell] |
Full Idea: Not all true beliefs are knowledge; the stock example to the contrary is that of a clock which has stopped by which I believe to be going and which I happen to look at when, by chance, it shows the right time. | |
From: Bertrand Russell (My Philosophical Development [1959], Ch.15) | |
A reaction: [in his 1948:112] Russell had spotted Gettier-type problems long before Gettier. The problem of lucky true beliefs dates back to Plato (Idea 2140). This example is also a problem for reliabilism, if the clock is usually working fine. |
6151 | Sartre says consciousness is just directedness towards external objects [Sartre, by Rowlands] |
Full Idea: Sartre defends a view of consciousness as nothing but a directedness towards objects, insisting that these objects are transcendent with respect to that consciousness; hence Sartre is one of the first genuine externalists. | |
From: report of Jean-Paul Sartre (Being and Nothingness [1943]) by Mark Rowlands - Externalism Ch.1 | |
A reaction: An ancestor here is, I think, Schopenhauer (Idea 4166). The idea is attractive, as we are brought up with idea that we have a thing called 'consciousness', but if you removed its contents there would literally be nothing left. |
6433 | Behaviourists struggle to explain memory and imagination, because they won't admit images [Russell] |
Full Idea: Behaviourists refuse to admit images because they cannot be observed from without, but this causes them difficulties when they attempt to explain either memory or imagination. | |
From: Bertrand Russell (My Philosophical Development [1959], Ch.13) | |
A reaction: This is a striking objection to behaviourism, and it is rarely mentioned in modern discussions of the topic. They might try denying the existence of private 'images', but that wouldn't be very plausible. |
6443 | Surprise is a criterion of error [Russell] |
Full Idea: Surprise is a criterion of error. | |
From: Bertrand Russell (My Philosophical Development [1959], Ch.15) | |
A reaction: Russell is not too precise about this, but it is a nice point. Surprise is thwarted expectation, which implies prior misjudgement. |
6164 | Sartre rejects mental content, and the idea that the mind has hidden inner features [Sartre, by Rowlands] |
Full Idea: Sartre's attack on the idea that consciousness has contents is an attack on the idea that the mental possesses features that are hidden, inner and constituted or revealed by the individual's inwardly directed awareness. | |
From: report of Jean-Paul Sartre (Being and Nothingness [1943]) by Mark Rowlands - Externalism Ch.5 | |
A reaction: This is part of the move towards 'externalism' about the mind. The notion of 'content' implies a container. It seems slightly ridiculous, though, to try to say that the mind just 'is the world'. How is reasoning possible, and the relation of ideas? |
6427 | Unverifiable propositions about the remote past are still either true or false [Russell] |
Full Idea: There is no conceivable method by which we can discover whether the proposition 'It snowed on Manhattan Island on the 1st January in the year 1 A.D.' is true or false, but it seems preposterous to maintain that it is neither. | |
From: Bertrand Russell (My Philosophical Development [1959], Ch.10) | |
A reaction: I love this example, which seems so simple and so clear-cut. It criticises verificationism, and gives strong intuitive support for realism, and supports the law of excluded middle. |
18791 | In 'situation semantics' our main concepts are abstracted from situations [Mares] |
Full Idea: In 'situation semantics' individuals, properties, facts, and events are treated as abstractions from situations. | |
From: Edwin D. Mares (Negation [2014], 6.1) | |
A reaction: [Barwise and Perry 1983 are cited] Since I take the process of abstraction to be basic to thought, I am delighted to learn that someone has developed a formal theory based on it. I am immediately sympathetic to situation semantics. |
6435 | You can believe the meaning of a sentence without thinking of the words [Russell] |
Full Idea: If you have just heard a loud clap of thunder, you believe what is expressed by 'there has just been a loud clap of thunder' even if no words come into your mind. | |
From: Bertrand Russell (My Philosophical Development [1959], Ch.13) | |
A reaction: This seems to me important, and accurate. We should not be too mesmerised by language. Animals have beliefs, and this is a nice example of an undeniable non-linguistic human belief. |
7074 | Man is a useless passion [Sartre] |
Full Idea: Man is a useless passion. | |
From: Jean-Paul Sartre (Being and Nothingness [1943], IV.2.III) | |
A reaction: Memorable and neat. Since all of existence is ultimately 'useless', that part of it is not a revelation. The notion that we are essentially a 'passion' chimes nicely with David Hume's view, against the enlightenment rational view, and against Aristotle. |
6687 | Man is the desire to be God [Sartre] |
Full Idea: Man fundamentally is the desire to be God. | |
From: Jean-Paul Sartre (Being and Nothingness [1943], p.556?), quoted by Gordon Graham - Eight Theories of Ethics Ch.5 | |
A reaction: It is better to see man (as seen all the way through the European tradition) as caught between the self-images of being an angel and being a 'quintessence of dust' (Hamlet). |
22228 | Sartre's freedom is not for whimsical action, but taking responsibility for our own values [Sartre, by Daigle] |
Full Idea: Readers often confuse Sartre's notion of freedom with the freedom of acting whimsically ....but since there is no God, we must create our own values. Freedom is not merely a licence to act whimsically.; it entails responsibility. | |
From: report of Jean-Paul Sartre (Being and Nothingness [1943]) by Christine Daigle - Jean-Paul Sartre 2.3 | |
A reaction: The idea that we create our values comes from Nietzsche. Did Sartre want everyone to behave like an übermensch? How can you form a society from individuals who create private values, even if they (somehow) take responsibility for them? |
22233 | Love is the demand to be loved [Sartre] |
Full Idea: Love is the demand to be loved. | |
From: Jean-Paul Sartre (Being and Nothingness [1943], p.488), quoted by Christine Daigle - Jean-Paul Sartre 2.5 | |
A reaction: Is that all love is? Hard to imagine someone loving another person without hoping that the other person will reciprocate. You need high self-esteem to 'demand' it. Low self-esteem merely hopes for it. He says the other person may feel the same. |
20755 | Fear concerns the world, but 'anguish' comes from confronting my self [Sartre] |
Full Idea: Anguish is distinguished from fear in that fear is fear of being in the world whereas anguish is anguish before myself. | |
From: Jean-Paul Sartre (Being and Nothingness [1943], p.65), quoted by Kevin Aho - Existentialism: an introduction 5 'Radical' | |
A reaction: I'm guessing that the anguish comes from the horror of the infinite choices available to me. Once you've made major life choices with full commitment (such as marriage), does that mean that existentialism becomes irrelevant? |
20760 | Sincerity is not authenticity, because it only commits to one particular identity [Sartre, by Aho] |
Full Idea: Being sincere [in Sartre] has nothing to do with authenticity because, in committing ourselves to a particular identity, we strip away the possibility of transcendence by reducing ourselves to a thing. | |
From: report of Jean-Paul Sartre (Being and Nothingness [1943]) by Kevin Aho - Existentialism: an introduction 6 'Bad' | |
A reaction: I take this to mean that sincerity says genuinely what role you are playing (such as a waiter), but authenticity is recognition that you don't have to play that role. I think. |
22231 | We flee from the anguish of freedom by seeing ourselves objectively, as determined [Sartre] |
Full Idea: We are always ready to take refuge in a belief in determinism if this freedom weighs upon us or if we need an excuse. Thus we flee from anguish by attempting to apprehend ourselves from without as an Other or a thing. | |
From: Jean-Paul Sartre (Being and Nothingness [1943], p.82), quoted by Christine Daigle - Jean-Paul Sartre 2.4 | |
A reaction: I would have thought we blame social pressures, or biological pressures, rather than metaphysical determinism, but it amounts to the same thing. If we are not free then probably nothing else is. |