34 ideas
| 22659 | It is wisdom to believe what you desire, because belief is needed to achieve it [James] |
| Full Idea: Clearly it is often the part of wisdom to believe what one desires; for the belief is one of indispensable preliminary conditions of the realisation of its object. | |
| From: William James (The Sentiment of Rationality [1882], p.43) | |
| A reaction: Roughly, action is impossible without optimism about possible success. This may count as instinct, rather than 'wisdom'. |
| 22657 | All good philosophers start from a dumb conviction about which truths can be revealed [James] |
| Full Idea: Every philosopher whose initiative counts for anything in the evolution of thought has taken his stand on a sort of dumb conviction that the truth must lie in one direction rather than another, and a preliminary assurance that this can be made to work. | |
| From: William James (The Sentiment of Rationality [1882], p.40) | |
| A reaction: I would refer to this as 'intuition', which I think of as reasons (probably good reasons) which cannot yet be articulated. Hence I like this idea very much, except for the word 'dumb'. It is more like a rational vision, yet to be filled in. |
| 22647 | A complete system is just a classification of the whole world's ingredients [James] |
| Full Idea: A completed theoretic philosophy can never be anything more than a completed classification of the world's ingredients. | |
| From: William James (The Sentiment of Rationality [1882], p.23) | |
| A reaction: I assume this is not just the physical ingredients, but must also include our conceptual scheme - but then we must first decide which is the best conceptual scheme to classify, and that's where the real action is. [He scorns such classifation later]. |
| 22648 | A single explanation must have a single point of view [James] |
| Full Idea: A single explanation of a fact only explains it from a single point of view. | |
| From: William James (The Sentiment of Rationality [1882], p.23) | |
| A reaction: I take this to imply that multiple viewpoints lead us towards objectivity. The single viewpoint of an expert is of much greater value than that of a novice, on the whole. |
| 22644 | Our greatest pleasure is the economy of reducing chaotic facts to one single fact [James] |
| Full Idea: Our pleasure at finding that a chaos of facts is the expression of single underlying fact is like a musician's relief at discovering harmony. …The passion for economy of means in thought is the philosophic passion par excellence. | |
| From: William James (The Sentiment of Rationality [1882], p.21) | |
| A reaction: We do, though, possess an inner klaxon warning against stupid simplistic reductions. Reducing all the miseries of life to the workings of the Devil is not satisfactory, even it it is economical. Simplicities are dangerously tempting. |
| 8729 | Intuitionists deny excluded middle, because it is committed to transcendent truth or objects [Shapiro] |
| Full Idea: Intuitionists in mathematics deny excluded middle, because it is symptomatic of faith in the transcendent existence of mathematical objects and/or the truth of mathematical statements. | |
| From: Stewart Shapiro (Thinking About Mathematics [2000], 1.2) | |
| A reaction: There are other problems with excluded middle, such as vagueness, but on the whole I, as a card-carrying 'realist', am committed to the law of excluded middle. |
| 8763 | The number 3 is presumably identical as a natural, an integer, a rational, a real, and complex [Shapiro] |
| Full Idea: It is surely wise to identify the positions in the natural numbers structure with their counterparts in the integer, rational, real and complex number structures. | |
| From: Stewart Shapiro (Thinking About Mathematics [2000], 10.2) | |
| A reaction: The point is that this might be denied, since 3, 3/1, 3.00.., and -3*i^2 are all arrived at by different methods of construction. Natural 3 has a predecessor, but real 3 doesn't. I agree, intuitively, with Shapiro. Russell (1919) disagreed. |
| 18249 | Cauchy gave a formal definition of a converging sequence. [Shapiro] |
| Full Idea: A sequence a1,a2,... of rational numbers is 'Cauchy' if for each rational number ε>0 there is a natural number N such that for all natural numbers m, n, if m>N and n>N then -ε < am - an < ε. | |
| From: Stewart Shapiro (Thinking About Mathematics [2000], 7.2 n4) | |
| A reaction: The sequence is 'Cauchy' if N exists. |
| 8764 | Categories are the best foundation for mathematics [Shapiro] |
| Full Idea: There is a dedicated contingent who hold that the category of 'categories' is the proper foundation for mathematics. | |
| From: Stewart Shapiro (Thinking About Mathematics [2000], 10.3 n7) | |
| A reaction: He cites Lawvere (1966) and McLarty (1993), the latter presenting the view as a form of structuralism. I would say that the concept of a category will need further explication, and probably reduce to either sets or relations or properties. |
| 8762 | Two definitions of 3 in terms of sets disagree over whether 1 is a member of 3 [Shapiro] |
| Full Idea: Zermelo said that for each number n, its successor is the singleton of n, so 3 is {{{null}}}, and 1 is not a member of 3. Von Neumann said each number n is the set of numbers less than n, so 3 is {null,{null},{null,{null}}}, and 1 is a member of 3. | |
| From: Stewart Shapiro (Thinking About Mathematics [2000], 10.2) | |
| A reaction: See Idea 645 - Zermelo could save Plato from the criticisms of Aristotle! These two accounts are cited by opponents of the set-theoretical account of numbers, because it seems impossible to arbitrate between them. |
| 8760 | Numbers do not exist independently; the essence of a number is its relations to other numbers [Shapiro] |
| Full Idea: The structuralist vigorously rejects any sort of ontological independence among the natural numbers; the essence of a natural number is its relations to other natural numbers. | |
| From: Stewart Shapiro (Thinking About Mathematics [2000], 10.1) | |
| A reaction: This seems to place the emphasis on ordinals (what order?) rather than on cardinality (how many?). I am strongly inclined to think that this is the correct view, though you can't really have relations if there is nothing to relate. |
| 8761 | A 'system' is related objects; a 'pattern' or 'structure' abstracts the pure relations from them [Shapiro] |
| Full Idea: A 'system' is a collection of objects with certain relations among them; a 'pattern' or 'structure' is the abstract form of a system, highlighting the interrelationships and ignoring any features they do not affect how they relate to other objects. | |
| From: Stewart Shapiro (Thinking About Mathematics [2000], 10.1) | |
| A reaction: Note that 'ignoring' features is a psychological account of abstraction, which (thanks to Frege and Geach) is supposed to be taboo - but which I suspect is actually indispensable in any proper account of thought and concepts. |
| 8744 | Logicism seems to be a non-starter if (as is widely held) logic has no ontology of its own [Shapiro] |
| Full Idea: The thesis that principles of arithmetic are derivable from the laws of logic runs against a now common view that logic itself has no ontology. There are no particular logical objects. From this perspective logicism is a non-starter. | |
| From: Stewart Shapiro (Thinking About Mathematics [2000], 5.1) | |
| A reaction: This criticism strikes me as utterly devastating. There are two routes to go: prove that logic does have an ontology of objects (what would they be?), or - better - deny that arithmetic contains any 'objects'. Or give up logicism. |
| 8749 | Term Formalism says mathematics is just about symbols - but real numbers have no names [Shapiro] |
| Full Idea: Term Formalism is the view that mathematics is just about characters or symbols - the systems of numerals and other linguistic forms. ...This will cover integers and rational numbers, but what are real numbers supposed to be, if they lack names? | |
| From: Stewart Shapiro (Thinking About Mathematics [2000], 6.1.1) | |
| A reaction: Real numbers (such as pi and root-2) have infinite decimal expansions, so we can start naming those. We could also start giving names like 'Harry' to other reals, though it might take a while. OK, I give up. |
| 8750 | Game Formalism is just a matter of rules, like chess - but then why is it useful in science? [Shapiro] |
| Full Idea: Game Formalism likens mathematics to chess, where the 'content' of mathematics is exhausted by the rules of operating with its language. ...This, however, leaves the problem of why the mathematical games are so useful to the sciences. | |
| From: Stewart Shapiro (Thinking About Mathematics [2000], 6.1.2) | |
| A reaction: This thought pushes us towards structuralism. It could still be a game, but one we learned from observing nature, which plays its own games. Chess is, after all, modelled on warfare. |
| 8752 | Deductivism says mathematics is logical consequences of uninterpreted axioms [Shapiro] |
| Full Idea: The Deductivist version of formalism (sometimes called 'if-thenism') says that the practice of mathematics consists of determining logical consequences of otherwise uninterpreted axioms. | |
| From: Stewart Shapiro (Thinking About Mathematics [2000], 6.2) | |
| A reaction: [Hilbert is the source] More plausible than Term or Game Formalism (qv). It still leaves the question of why it seems applicable to nature, and why those particular axioms might be chosen. In some sense, though, it is obviously right. |
| 8753 | Critics resent the way intuitionism cripples mathematics, but it allows new important distinctions [Shapiro] |
| Full Idea: Critics commonly complain that the intuitionist restrictions cripple the mathematician. On the other hand, intuitionist mathematics allows for many potentially important distinctions not available in classical mathematics, and is often more subtle. | |
| From: Stewart Shapiro (Thinking About Mathematics [2000], 7.1) | |
| A reaction: The main way in which it cripples is its restriction on talk of infinity ('Cantor's heaven'), which was resented by Hilbert. Since high-level infinities are interesting, it would be odd if we were not allowed to discuss them. |
| 8731 | Conceptualist are just realists or idealist or nominalists, depending on their view of concepts [Shapiro] |
| Full Idea: I classify conceptualists according to what they say about properties or concepts. If someone classified properties as existing independent of language I would classify her as a realist in ontology of mathematics. Or they may be idealists or nominalists. | |
| From: Stewart Shapiro (Thinking About Mathematics [2000], 2.2.1) | |
| A reaction: In other words, Shapiro wants to eliminate 'conceptualist' as a useful label in philosophy of mathematics. He's probably right. All thought involves concepts, but that doesn't produce a conceptualist theory of, say, football. |
| 8730 | 'Impredicative' definitions refer to the thing being described [Shapiro] |
| Full Idea: A definition of a mathematical entity is 'impredicative' if it refers to a collection that contains the defined entity. The definition of 'least upper bound' is impredicative as it refers to upper bounds and characterizes a member of this set. | |
| From: Stewart Shapiro (Thinking About Mathematics [2000], 1.2) | |
| A reaction: The big question is whether mathematics can live with impredicative definitions, or whether they threaten to be viciously circular, and undermine the whole enterprise. |
| 22649 | Classification can only ever be for a particular purpose [James] |
| Full Idea: Every way of classifying a thing is but a way of handling it for some particular purpose. Conceptions, 'kinds', are teleological instruments. | |
| From: William James (The Sentiment of Rationality [1882], p.24) | |
| A reaction: Could there not be ways of classifying which suit all of our purposes? If there were a naturally correct way to classifying things, then any pragmatist would probably welcome that. (I don't say there is such a way). |
| 8725 | Rationalism tries to apply mathematical methodology to all of knowledge [Shapiro] |
| Full Idea: Rationalism is a long-standing school that can be characterized as an attempt to extend the perceived methodology of mathematics to all of knowledge. | |
| From: Stewart Shapiro (Thinking About Mathematics [2000], 1.1) | |
| A reaction: Sometimes called 'Descartes's Dream', or the 'Enlightenment Project', the dream of proving everything. Within maths, Hilbert's Programme aimed for the same certainty. Idea 22 is the motto for the opposition to this approach. |
| 22655 | Scientific genius extracts more than other people from the same evidence [James] |
| Full Idea: What is the use of being a genius, unless with the same scientific evidence as other men, one can reach more truth than they? | |
| From: William James (The Sentiment of Rationality [1882], p.40) | |
| A reaction: This is aimed at Clifford's famous principle. He isn't actually contraverting the principle, but it is a nice point about evidence. Simple empiricists think detectives only have to stare at the evidence and the solution creates itself. |
| 22658 | Experimenters assume the theory is true, and stick to it as long as result don't disappoint [James] |
| Full Idea: Each tester of the truth of a theory …acts as if it were true, and expects the result to disappoint him if his assumption is false. The longer disappointment is delayed, the stronger grows his faith in his theory. | |
| From: William James (The Sentiment of Rationality [1882], p.42) | |
| A reaction: This is almost exactly Popper's falsificationist proposal for science, which interestingly shows the close relationship of his view to pragmatism. Believe it as long as it is still working. |
| 22654 | We can't know if the laws of nature are stable, but we must postulate it or assume it [James] |
| Full Idea: That nature will follow tomorrow the same laws that she follows today is a truth which no man can know; but in the interests of cognition as well as of action we must postulate or assume it. | |
| From: William James (The Sentiment of Rationality [1882], p.39) | |
| A reaction: The stability of nature is something to be assessed, not something taken for granted. If you arrive in a new city and it all seems quiet, you keep your fingers crossed and treat it as stable. But revolution or coup could be just round the corner. |
| 22656 | Trying to assess probabilities by mere calculation is absurd and impossible [James] |
| Full Idea: The absurd abstraction of an intellect verbally formulating all its evidence and carefully estimating the probability thereof solely by the size of a vulgar fraction, is as ideally inept as it is practically impossible. | |
| From: William James (The Sentiment of Rationality [1882], p.40) | |
| A reaction: James probably didn't know about Bayes, but this is directed at the Bayesian approach. My view is that full rational assessment of coherence is a much better bet than a Bayesian calculation. Factors must be weighted. |
| 22646 | We have a passion for knowing the parts of something, rather than the whole [James] |
| Full Idea: Alongside the passion for simplification …is the passion for distinguishing; it is the passion to be acquainted with the parts rather than to comprehend the whole. | |
| From: William James (The Sentiment of Rationality [1882], p.22) | |
| A reaction: As I child I dismantled almost every toy I was given. This seems to be the motivation for a lot of analytic philosophy, but Aristotle also tended to think that way. |
| 22652 | The mind has evolved entirely for practical interests, seen in our reflex actions [James] |
| Full Idea: It is far too little recognised how entirely the intellect is built up of practical interests. The theory of evolution is beginning to do very good service by its reduction of all mentality to the type of reflex action. | |
| From: William James (The Sentiment of Rationality [1882], p.34) | |
| A reaction: Hands evolved for manipulating tools end up playing the piano. Minds evolved for action can be afflicted with boredom. He's not wrong, but he is risking the etymological fallacy (origin = purpose). I take navigation to be the original purpose of mind. |
| 22651 | Dogs' curiosity only concerns what will happen next [James] |
| Full Idea: A dog's curiosity about the movements of his master or a strange object only extends as far as the point of what is going to happen next. | |
| From: William James (The Sentiment of Rationality [1882], p.31) | |
| A reaction: Good. A nice corrective to people like myself who are tempted to inflate animal rationality, in order to emphasise human evolutionary continuity with them. It is hard to disagree with his observation. But dogs do make judgements! True/false! |
| 12727 | It's impossible, but imagine a body carrying on normally, but with no mind [Leibniz] |
| Full Idea: If it could be supposed that a body exists without a mind, then a man would do everything in the same way as if he did not have a mind, and men would speak and write the same things, without knowing what they do. ...But this supposition is impossible. | |
| From: Gottfried Leibniz (Paper of December 1676 [1676], A6.3.400), quoted by Daniel Garber - Leibniz:Body,Substance,Monad 5 | |
| A reaction: This is clearly the zombie dream, three centuries before Robert Kirk's modern invention of the idea. Leibniz's reason for denying the possibility of zombies won't be the modern physicalist reason. |
| 22650 | How can the ground of rationality be itself rational? [James] |
| Full Idea: Can that which is the ground of rationality in all else be itself properly called rational? | |
| From: William James (The Sentiment of Rationality [1882], p.25) | |
| A reaction: This is the perennial problem in deciding grounds, and in deciding what to treat as primitive. The stoics see the whole of nature as rational. Cf how can the ground of what is physical be itself physical? |
| 22643 | It seems that we feel rational when we detect no irrationality [James] |
| Full Idea: I think there are very good grounds for upholding the view that the feeling of rationality is constituted merely by the absence of any feelings of irrationality. | |
| From: William James (The Sentiment of Rationality [1882], p.20) | |
| A reaction: A very interesting proposal. Nothing is more basic to logic (well, plausible versions of logic) than the principle of non-contradiction - perhaps because it is the foundation of our natural intellectual equipment. |
| 22660 | Evolution suggests prevailing or survival as a new criterion of right and wrong [James] |
| Full Idea: The philosophy of evolution offers us today a new criterion, which is objective and fixed, as an ethical test between right and wrong: That is to be called good which is destined to prevail or survive. | |
| From: William James (The Sentiment of Rationality [1882], p.44) | |
| A reaction: Perceptive for its time. Herbert Spencer may have suggested the idea. James dismisses it, because it implies a sort of fatalism, whereas genuine moral choices are involved in what survives. |
| 22645 | Understanding by means of causes is useless if they are not reduced to a minimum number [James] |
| Full Idea: The knowledge of things by their causes, which is often given as a definition of rational knowledge, is useless unless the causes converge to a minimum number, while still producing the maximum number of effects. | |
| From: William James (The Sentiment of Rationality [1882], p.21) | |
| A reaction: This is certainly the psychological motivation for trying to identify 'the' cause of something, but James always tries to sell such things as subjective. 'Useless' to one person is a subjective criterion; useless to anyone is much more objective. |
| 22653 | Early Christianity says God recognises the neglected weak and tender impulses [James] |
| Full Idea: In what did the emancipating message of primitive Christianity consist but in the announcement that God recognizes those weak and tender impulses which paganism had so rudely overlooked. | |
| From: William James (The Sentiment of Rationality [1882], p.36) | |
| A reaction: Nietzsche says these are the virtues of a good slave. Previous virtues were dominated by military needs, but the new virtues are those of large cities, where communal living with strangers is the challenge. |