46 ideas
| 3240 | There is more insight in fundamental perplexity about problems than in their supposed solutions [Nagel] |
| Full Idea: Certain forms of perplexity (say about freedom, knowledge and the meaning of life) seem to me to embody more insight than any of the supposed solutions to those problems. | |
| From: Thomas Nagel (The View from Nowhere [1986], Intro) | |
| A reaction: Obviously false solutions won't embody much insight. This sounds good, but I suspect that the insight is in the recognition of the facts which give rise to the perplexity. I can't think of anything in favour of perplexity for its own sake. |
| 3242 | Philosophy is the childhood of the intellect, and a culture can't skip it [Nagel] |
| Full Idea: Philosophy is the childhood of the intellect, and a culture that tries to skip it will never grow up. | |
| From: Thomas Nagel (The View from Nowhere [1986], Intro) | |
| A reaction: Can he really mean that a mature culture doesn't need philosophy? |
| 3241 | It seems mad, but the aim of philosophy is to climb outside of our own minds [Nagel] |
| Full Idea: We are trying to climb outside of our own minds, an effort that some would regard as insane and that I regard as philosophically fundamental. | |
| From: Thomas Nagel (The View from Nowhere [1986], Intro) | |
| A reaction: It is not only philosophers who do this. It is an essential feature of the mind, and is inherent in the concept of truth. |
| 13939 | No possible evidence could decide the reality of numbers, so it is a pseudo-question [Carnap] |
| Full Idea: I cannot think of any possible evidence that would be regarded as relevant by both nominalists and realists about numbers, and would decide the controversy, or make one side more probable. Hence I regard the external questions as pseudo-questions. | |
| From: Rudolph Carnap (Empiricism, Semantics and Ontology [1950], 4) |
| 3248 | Realism invites scepticism because it claims to be objective [Nagel] |
| Full Idea: The search for objective knowledge, because of its commitment to realism, cannot refute scepticism and must proceed under its shadow, and scepticism is only a problem because of the realist claims of objectivity. | |
| From: Thomas Nagel (The View from Nowhere [1986], V.1) |
| 20989 | Views are objective if they don't rely on a person's character, social position or species [Nagel] |
| Full Idea: A view or form of thought is more objective than another if it relies less on the specifics of the individual's makeup and position in the world, or on the character of the particular type of creature he is. | |
| From: Thomas Nagel (The View from Nowhere [1986], Intro) | |
| A reaction: Notice that this defines comparative objectivity, rather than an absolute. I take it that something must be entirely objective to qualify as a 'fact', and so anything about which there is a consensus that it is a fact can be taken as wholly objective. |
| 22354 | Things cause perceptions, properties have other effects, hence we reach a 'view from nowhere' [Nagel, by Reiss/Sprenger] |
| Full Idea: First we realise that perceptions are caused by things, second we realise that properties have other effects (as well as causing perceptions), and third we conceive of a thing's true nature without perspectives. That is the 'view from nowhere'. | |
| From: report of Thomas Nagel (The View from Nowhere [1986], p.14) by Reiss,J/Spreger,J - Scientific Objectivity 2.1 | |
| A reaction: [My summary of their summary] This is obviously an optimistic view. I''m not sure how he can justify three precise stages, given than animals probably jump straight to the third stage, and engage with the nature's of things. |
| 13838 | A decent modern definition should always imply a semantics [Hacking] |
| Full Idea: Today we expect that anything worth calling a definition should imply a semantics. | |
| From: Ian Hacking (What is Logic? [1979], §10) | |
| A reaction: He compares this with Gentzen 1935, who was attempting purely syntactic definitions of the logical connectives. |
| 13833 | 'Thinning' ('dilution') is the key difference between deduction (which allows it) and induction [Hacking] |
| Full Idea: 'Dilution' (or 'Thinning') provides an essential contrast between deductive and inductive reasoning; for the introduction of new premises may spoil an inductive inference. | |
| From: Ian Hacking (What is Logic? [1979], §06.2) | |
| A reaction: That is, inductive logic (if there is such a thing) is clearly non-monotonic, whereas classical inductive logic is monotonic. |
| 13834 | Gentzen's Cut Rule (or transitivity of deduction) is 'If A |- B and B |- C, then A |- C' [Hacking] |
| Full Idea: If A |- B and B |- C, then A |- C. This generalises to: If Γ|-A,Θ and Γ,A |- Θ, then Γ |- Θ. Gentzen called this 'cut'. It is the transitivity of a deduction. | |
| From: Ian Hacking (What is Logic? [1979], §06.3) | |
| A reaction: I read the generalisation as 'If A can be either a premise or a conclusion, you can bypass it'. The first version is just transitivity (which by-passes the middle step). |
| 13835 | Only Cut reduces complexity, so logic is constructive without it, and it can be dispensed with [Hacking] |
| Full Idea: Only the cut rule can have a conclusion that is less complex than its premises. Hence when cut is not used, a derivation is quite literally constructive, building up from components. Any theorem obtained by cut can be obtained without it. | |
| From: Ian Hacking (What is Logic? [1979], §08) |
| 13845 | The various logics are abstractions made from terms like 'if...then' in English [Hacking] |
| Full Idea: I don't believe English is by nature classical or intuitionistic etc. These are abstractions made by logicians. Logicians attend to numerous different objects that might be served by 'If...then', like material conditional, strict or relevant implication. | |
| From: Ian Hacking (What is Logic? [1979], §15) | |
| A reaction: The idea that they are 'abstractions' is close to my heart. Abstractions from what? Surely 'if...then' has a standard character when employed in normal conversation? |
| 13840 | First-order logic is the strongest complete compact theory with Löwenheim-Skolem [Hacking] |
| Full Idea: First-order logic is the strongest complete compact theory with a Löwenheim-Skolem theorem. | |
| From: Ian Hacking (What is Logic? [1979], §13) |
| 13844 | A limitation of first-order logic is that it cannot handle branching quantifiers [Hacking] |
| Full Idea: Henkin proved that there is no first-order treatment of branching quantifiers, which do not seem to involve any idea that is fundamentally different from ordinary quantification. | |
| From: Ian Hacking (What is Logic? [1979], §13) | |
| A reaction: See Hacking for an example of branching quantifiers. Hacking is impressed by this as a real limitation of the first-order logic which he generally favours. |
| 13842 | Second-order completeness seems to need intensional entities and possible worlds [Hacking] |
| Full Idea: Second-order logic has no chance of a completeness theorem unless one ventures into intensional entities and possible worlds. | |
| From: Ian Hacking (What is Logic? [1979], §13) |
| 13837 | With a pure notion of truth and consequence, the meanings of connectives are fixed syntactically [Hacking] |
| Full Idea: My doctrine is that the peculiarity of the logical constants resides precisely in that given a certain pure notion of truth and consequence, all the desirable semantic properties of the constants are determined by their syntactic properties. | |
| From: Ian Hacking (What is Logic? [1979], §09) | |
| A reaction: He opposes this to Peacocke 1976, who claims that the logical connectives are essentially semantic in character, concerned with the preservation of truth. |
| 13839 | Perhaps variables could be dispensed with, by arrows joining places in the scope of quantifiers [Hacking] |
| Full Idea: For some purposes the variables of first-order logic can be regarded as prepositions and place-holders that could in principle be dispensed with, say by a system of arrows indicating what places fall in the scope of which quantifier. | |
| From: Ian Hacking (What is Logic? [1979], §11) | |
| A reaction: I tend to think of variables as either pronouns, or as definite descriptions, or as temporary names, but not as prepositions. Must address this new idea... |
| 13843 | If it is a logic, the Löwenheim-Skolem theorem holds for it [Hacking] |
| Full Idea: A Löwenheim-Skolem theorem holds for anything which, on my delineation, is a logic. | |
| From: Ian Hacking (What is Logic? [1979], §13) | |
| A reaction: I take this to be an unusually conservative view. Shapiro is the chap who can give you an alternative view of these things, or Boolos. |
| 13936 | Questions about numbers are answered by analysis, and are analytic, and hence logically true [Carnap] |
| Full Idea: For the internal question like 'is there a prime number greater than a hundred?' the answers are found by logical analysis based on the rules for the new expressions. The answers here are analytic, i.e., logically true. | |
| From: Rudolph Carnap (Empiricism, Semantics and Ontology [1950], 2) |
| 8748 | Logical positivists incorporated geometry into logicism, saying axioms are just definitions [Carnap, by Shapiro] |
| Full Idea: The logical positivists brought geometry into the fold of logicism. The axioms of, say, Euclidean geometry are simply definitions of primitive terms like 'point' and 'line'. | |
| From: report of Rudolph Carnap (Empiricism, Semantics and Ontology [1950]) by Stewart Shapiro - Thinking About Mathematics 5.3 | |
| A reaction: If the concept of 'line' is actually created by its definition, then we need to know exactly what (say) 'shortest' means. If we are merely describing a line, then our definition can be 'impredicative', using other accepted concepts. |
| 8960 | Internal questions about abstractions are trivial, and external ones deeply problematic [Carnap, by Szabó] |
| Full Idea: Carnap's verdict is that questions regarding the existence of abstracta tend to be trivial when taken as internal and deeply problematic when taken as external. | |
| From: report of Rudolph Carnap (Empiricism, Semantics and Ontology [1950]) by Zoltán Gendler Szabó - Nominalism 6 | |
| A reaction: If the internal aspect of the problem is 'trivial', this would put Carnap in league with fictionalists, who are only committed to entities while playing the current game. What is the status of the theory? Carnap wanted flowers to bloom. |
| 13933 | Existence questions are 'internal' (within a framework) or 'external' (concerning the whole framework) [Carnap] |
| Full Idea: We distinguish two kinds of existence questions: first, entities of a new kind within the framework; we call them 'internal questions'. Second, 'external questions', concerning the existence or reality of the system of entities as a whole. | |
| From: Rudolph Carnap (Empiricism, Semantics and Ontology [1950], 2) | |
| A reaction: This nicely disposes of many ontological difficulties, but at the price of labelling most external questions as meaningless, so that the internal answers have very little commitment, and the external (big) questions are now banned. Not for me. |
| 13934 | To be 'real' is to be an element of a system, so we cannot ask reality questions about the system itself [Carnap] |
| Full Idea: To be real in the scientific sense means to be an element of the system; hence this concept cannot be meaningfully applied to the system itself. | |
| From: Rudolph Carnap (Empiricism, Semantics and Ontology [1950], 2) |
| 13938 | A linguistic framework involves commitment to entities, so only commitment to the framework is in question [Carnap] |
| Full Idea: If someone accepts a framework for a kind of entities, then he must admit the entities as possible designata. Thus the question of the admissibility of entities is reduced to the question of the acceptability of the linguistic framework for the entities. | |
| From: Rudolph Carnap (Empiricism, Semantics and Ontology [1950], 4) | |
| A reaction: Despite the many differences of opinion between Quine and Carnap, this appears to be a straight endorsement by Carnap of the Quinean conception of ontological commitment. |
| 13935 | We only accept 'things' within a language with formation, testing and acceptance rules [Carnap] |
| Full Idea: To accept the thing world means nothing more than to accept a certain form of language, in other words, to accept rules for forming statements and for testing, accepting, or rejecting them. | |
| From: Rudolph Carnap (Empiricism, Semantics and Ontology [1950], 2) | |
| A reaction: If you derive your metaphysics from your language, then objects are linguistic conventions. But why do we accept conventions about objects? |
| 3249 | Modern science depends on the distinction between primary and secondary qualities [Nagel] |
| Full Idea: The distinction between primary and secondary qualities is the precondition for the development of modern physics and chemistry. | |
| From: Thomas Nagel (The View from Nowhere [1986], V.3) |
| 22429 | We achieve objectivity by dropping secondary qualities, to focus on structural primary qualities [Nagel] |
| Full Idea: At the end [of the three stages of objectivity] the secondary qualities drop out of our picture of the external world, and the underlyiing primary qualities such as shape, size, weight, and motion are thought of structurally. | |
| From: Thomas Nagel (The View from Nowhere [1986], II) | |
| A reaction: This is the orthodox view for realists about the external world, and I largely agree. The only problem I see is that secondary qualities contain information, such as the colour of rotting fruit - but then colour is not an essential feature of rot. |
| 13932 | Empiricists tend to reject abstract entities, and to feel sympathy with nominalism [Carnap] |
| Full Idea: Empiricists are in general rather suspicious with respect to any kind of abstract entities like properties, classes, relations, numbers, propositions etc. They usually feel more sympathy with nominalists than with realists (in the medieval sense). | |
| From: Rudolph Carnap (Empiricism, Semantics and Ontology [1950], 1) | |
| A reaction: The obvious reason is that you can't have sense experiences of abstract entities. I like the question 'what are they made of?' rather than the question 'how can I experience them?'. |
| 13937 | New linguistic claims about entities are not true or false, but just expedient, fruitful or successful [Carnap] |
| Full Idea: The acceptance of new linguistic forms about entities cannot be judged as being either true or false because it is not an assertion. It can only be judged as being more or less expedient, fruitful, conducive to the aim for which the language is intended. | |
| From: Rudolph Carnap (Empiricism, Semantics and Ontology [1950], 3) | |
| A reaction: The obvious problem seems to be that a complete pack of lies might be successful for a very long time, if it plugged a critical hole in a major theory. Is success judged financially? How do we judge success without mentioning truth? |
| 3247 | Epistemology is centrally about what we should believe, not the definition of knowledge [Nagel] |
| Full Idea: The central problem of epistemology is what to believe and how to justify one's beliefs, not the impersonal problem of whether my beliefs can be said to be knowledge. | |
| From: Thomas Nagel (The View from Nowhere [1986], V.1) | |
| A reaction: Wrong. The question of whether what one has is 'knowledge' is not impersonal at all - it is having the social status of a knower or expert. |
| 3252 | Scepticism is based on ideas which scepticism makes impossible [Nagel] |
| Full Idea: The sceptic reaches scepticism through thoughts that scepticism makes unthinkable. | |
| From: Thomas Nagel (The View from Nowhere [1986], V.6) |
| 13940 | All linguistic forms in science are merely judged by their efficiency as instruments [Carnap] |
| Full Idea: The acceptance or rejection of abstract (or any other) linguistic forms in any branch of science will finally be decided by their efficiency as instruments. | |
| From: Rudolph Carnap (Empiricism, Semantics and Ontology [1950], 5) |
| 3251 | Observed regularities are only predictable if we assume hidden necessity [Nagel] |
| Full Idea: Observed regularities provide reason to believe that they will be repeated only to the extent that they provide evidence of hidden necessary connections, which hold timelessly. | |
| From: Thomas Nagel (The View from Nowhere [1986], V.5) |
| 3244 | Personal identity cannot be fully known a priori [Nagel] |
| Full Idea: The full conditions of personal identity cannot be extracted from the concept of a person at all: they cannot be arrived at a priori. | |
| From: Thomas Nagel (The View from Nowhere [1986], III.2) | |
| A reaction: However, if you turn to experience to get the hang of what a person is, it is virtually impossible to disentangle the essentials from the accidental features of being a person. How essential are memories or reasoning or hopes or understandings or plans? |
| 3245 | The question of whether a future experience will be mine presupposes personal identity [Nagel] |
| Full Idea: The identity of the self must have some sort of objectivity, otherwise the subjective question whether a future experience will be mine or not will be contentless. | |
| From: Thomas Nagel (The View from Nowhere [1986], III.3) | |
| A reaction: This sounds a bit circular and question-begging. If there is no objective self, then the question of whether a future experience will be mine would be a misconceived question. I sympathise with Nagel's attempt to show how personal identity is a priori. |
| 3246 | I can't even conceive of my brain being split in two [Nagel] |
| Full Idea: It is hard to think of myself as being identical with my brain. If my brain is to be split, with one half miserable and the other half euphoric, my expectations can take no form, as my idea of myself doesn't allow for divisibility. | |
| From: Thomas Nagel (The View from Nowhere [1986], III.4) | |
| A reaction: Nagel is trying to imply that there is some sort of conceptual impossibility here, but it may just be very difficult. I can think about my lovely lunch while doing my miserable job. Does Nagel want to hang on to a unified thing which doesn't exist? |
| 3257 | Total objectivity can't see value, but it sees many people with values [Nagel] |
| Full Idea: A purely objective view has no way of knowing whether anything has any value, but actually its data include the appearance of value to individuals with particular perspectives, including oneself. | |
| From: Thomas Nagel (The View from Nowhere [1986], VIII.2) | |
| A reaction: I would have thought that a very objective assessment of someone's health is an obvious revelation of value, irrespective of anyone's particular perspective. |
| 3265 | We don't worry about the time before we were born the way we worry about death [Nagel] |
| Full Idea: We do not regard the period before we were born in the same way that we regard the prospect of death. | |
| From: Thomas Nagel (The View from Nowhere [1986], XI.3) | |
| A reaction: This is a challenge to Epicurus, who said death is no worse than pre-birth. This idea may be true of the situation immediately post-death, but a thousand years from now it is hard to distinguish them. |
| 3263 | If our own life lacks meaning, devotion to others won't give it meaning [Nagel] |
| Full Idea: If no one's life has any meaning in itself, how can it acquire meaning through devotion to the meaningless lives of others? | |
| From: Thomas Nagel (The View from Nowhere [1986], XI.2) | |
| A reaction: This is one of the paradoxes of compassion. The other is that the virtue requires other people to be in need of help, which can't be a desirable situation. |
| 3256 | Pain doesn't have a further property of badness; it gives a reason for its avoidance [Nagel] |
| Full Idea: The objective badness of pain is not some mysterious further property that all pains have, but just the fact that there is reason for anyone capable of viewing the world objectively to want it to stop. | |
| From: Thomas Nagel (The View from Nowhere [1986], VIII.2) | |
| A reaction: Presumably all pains (e.g. of grief and of toothache) have something in common, to qualify as pains. It must be more than being disliked, because we can dislike a food. |
| 3261 | Something may be 'rational' either because it is required or because it is acceptable [Nagel] |
| Full Idea: "Rational" may mean rationally required or rationally acceptable | |
| From: Thomas Nagel (The View from Nowhere [1986], X.4) |
| 3258 | If cockroaches can't think about their actions, they have no duties [Nagel] |
| Full Idea: If cockroaches cannot think about what they should do, there is nothing they should do. | |
| From: Thomas Nagel (The View from Nowhere [1986], VIII.3) |
| 3254 | If we can decide how to live after stepping outside of ourselves, we have the basis of a moral theory [Nagel] |
| Full Idea: If we can make judgements about how we should live even after stepping outside of ourselves, they will provide the material for moral theory. | |
| From: Thomas Nagel (The View from Nowhere [1986], VIII.1) |
| 3264 | We should see others' viewpoints, but not lose touch with our own values [Nagel] |
| Full Idea: One should occupy a position far enough outside your own life to reduce the importance of the difference between yourself and other people, yet not so far outside that all human values vanish in a nihilistic blackout (i.e.aim for a form of humility). | |
| From: Thomas Nagel (The View from Nowhere [1986], XI.2) |
| 3255 | We find new motives by discovering reasons for action different from our preexisting motives [Nagel] |
| Full Idea: There are reasons for action, and we must discover them instead of deriving them from our preexisting motives - and in that way we can acquire new motives superior to the old. | |
| From: Thomas Nagel (The View from Nowhere [1986], VIII.1) |
| 3262 | Utilitarianism is too demanding [Nagel] |
| Full Idea: Utilitarianism is too demanding. | |
| From: Thomas Nagel (The View from Nowhere [1986], X.5) |