51 ideas
| 18290 | But what is the reasoning of the body, that it requires the wisdom you seek? [Nietzsche] |
| Full Idea: There is more reason in your body than in your best wisdom. For who knows for what purpose your body requires precisely your best wisdom? | |
| From: Friedrich Nietzsche (Thus Spake Zarathustra [1884], 1.05) | |
| A reaction: Lovely question. For years I've paid lip-service to wisdom as the rough aim of all philosophy. Not quite knowing what wisdom is doesn't bother me, but knowing why I want wisdom certainly does, especially after this idea. |
| 19066 | Philosophy aims to understand the world, through ordinary experience and science [Dummett] |
| Full Idea: Philosophy is an attempt to understand the world, as it is revealed to us both in our ordinary experience and by the discoveries and theories of science. | |
| From: Michael Dummett (The Justification of Deduction [1973], p.311) | |
| A reaction: I don't see a sharp division between 'ordinary' and 'scientific'. I really like this idea, first because it makes 'understanding' central, and second because it wants both revelations. In discussing matter and time, there is too much emphasis on science. |
| 18303 | Reject wisdom that lacks laughter [Nietzsche] |
| Full Idea: Let that wisdom be false to us that brought no laughter with it! | |
| From: Friedrich Nietzsche (Thus Spake Zarathustra [1884], 3.12.23) |
| 19067 | A successful proof requires recognition of truth at every step [Dummett] |
| Full Idea: For a demonstration to be cogent it is necessary that the passage from step to step involve a recognition of truth at each line. | |
| From: Michael Dummett (The Justification of Deduction [1973], p.313) | |
| A reaction: Dummett cited Quine (esp. 1970) as having an almost entirely syntactic view of logic. Rumfitt points out that logic can move validly from one falsehood to another. Even a 'proof' might detour into falsehood, but it would not be a 'canonical' proof! |
| 18305 | To love truth, you must know how to lie [Nietzsche] |
| Full Idea: Inability to lie is far from being love of truth. ....He who cannot lie does not know what truth is. | |
| From: Friedrich Nietzsche (Thus Spake Zarathustra [1884], 4.13.9) |
| 19060 | Truth-tables are dubious in some cases, and may be a bad way to explain connective meaning [Dummett] |
| Full Idea: It is arguable whether two-valued truth tables give correct meanings for certain sentential operators, and even whether they constitute legitimate explanations of any possible sentential operators. | |
| From: Michael Dummett (The Justification of Deduction [1973], p.294) | |
| A reaction: See 'Many-valued logic' for examples of non-binary truth tables. Presumably logicians should aspire to make their semantics precise, as well as their syntax. |
| 9065 | S5 collapses iterated modalities (◊□P→□P, and ◊◊P→◊P) [Keefe/Smith] |
| Full Idea: S5 collapses iterated modalities (so ◊□P → □P, and ◊◊P → ◊P). | |
| From: R Keefe / P Smith (Intro: Theories of Vagueness [1997], §5) | |
| A reaction: It is obvious why this might be controversial, and there seems to be a general preference for S4. There may be confusions of epistemic and ontic (and even semantic?) possibilities within a single string of modalities. |
| 11066 | Deduction is justified by the semantics of its metalanguage [Dummett, by Hanna] |
| Full Idea: For Dummett the semantics of the metalanguage is the external and objective source of the justification of deduction. | |
| From: report of Michael Dummett (The Justification of Deduction [1973]) by Robert Hanna - Rationality and Logic 3.4 | |
| A reaction: This is offered as an answer to the Lewis Carroll problem that justifying deduction seems to need deduction, thus leading to a regress. [There is a reply to Dummett by Susan Haack] |
| 19058 | Syntactic consequence is positive, for validity; semantic version is negative, with counterexamples [Dummett] |
| Full Idea: A plausible account is that the syntactic notion of consequence is for positive results, that some form of argument is valid; the semantic notion is required for negative results, that some argument is invalid, because a counterexample can be found. | |
| From: Michael Dummett (The Justification of Deduction [1973], p.292) | |
| A reaction: This rings true for the two strategies of demonstration, the first by following the rules in steps, the second by using your imagination (or a tableau) to think up problems. |
| 19063 | Beth trees show semantics for intuitionistic logic, in terms of how truth has been established [Dummett] |
| Full Idea: Beth trees give a semantics for intuitionistic logic, by representing sentence meaning in terms of conditions under which it is recognised to have been established as true. | |
| From: Michael Dummett (The Justification of Deduction [1973], p.305) |
| 19059 | In standard views you could replace 'true' and 'false' with mere 0 and 1 [Dummett] |
| Full Idea: Nothing is lost, on this view, if in the standard semantic treatment of classical sentential logic, we replace the standard truth-values 'true' and 'false' by the numbers 0 and 1. | |
| From: Michael Dummett (The Justification of Deduction [1973], p.294) | |
| A reaction: [A long context will explain 'on this view'] He is discussing the relationship of syntactic and semantic consequence, and goes on to criticise simple binary truth-table accounts of connectives. Semantics on a computer would just be 0 and 1. |
| 19062 | Classical two-valued semantics implies that meaning is grasped through truth-conditions [Dummett] |
| Full Idea: The standard two-valued semantics for classical logic involves a conception under which to grasp the meaning of a sentence is to apprehend the conditions under which it is, or is not, true. | |
| From: Michael Dummett (The Justification of Deduction [1973], p.305) | |
| A reaction: The idea is that you only have to grasp the truth tables for sentential logic, and that needs nothing more than knowing whether a sentence is true or false. I'm not sure where the 'conditions' creep in, though. |
| 19065 | Soundness and completeness proofs test the theory of meaning, rather than the logic theory [Dummett] |
| Full Idea: A proof of soundess or completeness is a test, not so much of the logical theory to which it applies, but of the theory of meaning which underlies the semantics. | |
| From: Michael Dummett (The Justification of Deduction [1973], p.310) | |
| A reaction: These two types of proof concern how the syntax and the semantics match up, so this claim sounds plausible, though I tend to think of them as more like roadworthiness tests for logic, checking how well they function. |
| 9064 | Objects such as a cloud or Mount Everest seem to have fuzzy boundaries in nature [Keefe/Smith] |
| Full Idea: A common intuition is that a vague object has indeterminate or fuzzy spatio-temporal boundaries, such as a cloud. Mount Everest can only have arbitrary boundaries placed around it, so in nature it must have fuzzy boundaries. | |
| From: R Keefe / P Smith (Intro: Theories of Vagueness [1997], §5) | |
| A reaction: We would have to respond by questioning whether Everest counts precisely as an 'object'. At the microscopic or subatomic level it seems that virtually everything has fuzzy boundaries. Maybe boundaries don't really exist. |
| 9044 | If someone is borderline tall, no further information is likely to resolve the question [Keefe/Smith] |
| Full Idea: If Tek is borderline tall, the unclarity does not seem to be epistemic, because no amount of further information about his exact height (or the heights of others) could help us decide whether he is tall. | |
| From: R Keefe / P Smith (Intro: Theories of Vagueness [1997], §1) | |
| A reaction: One should add also that information about social conventions or conventions about the usage of the word 'tall' will not help either. It seems fairly obvious that God would not know whether Tek is tall, so the epistemic view is certainly counterintuitive. |
| 9048 | The simplest approach, that vagueness is just ignorance, retains classical logic and semantics [Keefe/Smith] |
| Full Idea: The simplest approach to vagueness is to retain classical logic and semantics. Borderline cases are either true or false, but we don't know which, and, despite appearances, vague predicates have well-defined extensions. Vagueness is ignorance. | |
| From: R Keefe / P Smith (Intro: Theories of Vagueness [1997], §1) | |
| A reaction: It seems to me that you must have a rather unhealthy attachment to the logicians' view of the world to take this line. It is the passion of the stamp collector, to want everything in sets, with neatly labelled properties, and inference lines marked out. |
| 9055 | The epistemic view of vagueness must explain why we don't know the predicate boundary [Keefe/Smith] |
| Full Idea: A key question for the epistemic view of vagueness is: why are we ignorant of the facts about where the boundaries of vague predicates lie? | |
| From: R Keefe / P Smith (Intro: Theories of Vagueness [1997], §2) | |
| A reaction: Presumably there is a range of answers, from laziness, to inability to afford the instruments, to limitations on human perception. At the limit, with physical objects, how do we tell whether it is us or the object which is afflicted with vagueness? |
| 9049 | Supervaluationism keeps true-or-false where precision can be produced, but not otherwise [Keefe/Smith] |
| Full Idea: The supervaluationist view of vagueness is that 'tall' comes out true or false on all the ways in which we can make 'tall' precise. There is a gap for borderline cases, but 'tall or not-tall' is still true wherever you draw a boundary. | |
| From: R Keefe / P Smith (Intro: Theories of Vagueness [1997], §1) | |
| A reaction: [Kit Fine is the spokesperson for this; it preserves classical logic, but not semantics] This doesn't seem to solve the problem of vagueness, but it does (sort of) save the principle of excluded middle. |
| 9056 | Vague statements lack truth value if attempts to make them precise fail [Keefe/Smith] |
| Full Idea: The supervaluationist view of vagueness proposes that a sentence is true iff it is true on all precisifications, false iff false on all precisifications, and neither true nor false otherwise. | |
| From: R Keefe / P Smith (Intro: Theories of Vagueness [1997], §3) | |
| A reaction: This seems to be just a footnote to the Russell/Unger view, that logic works if the proposition is precise, but otherwise it is either just the mess of ordinary life, or the predicate doesn't apply at all. |
| 9058 | Some of the principles of classical logic still fail with supervaluationism [Keefe/Smith] |
| Full Idea: Supervaluationist logic (now with a 'definite' operator D) fails to preserve certain classical principles about consequence and rules of inference. For example, reduction ad absurdum, contraposition, the deduction theorem and argument by cases. | |
| From: R Keefe / P Smith (Intro: Theories of Vagueness [1997], §3) | |
| A reaction: The aim of supervaluationism was to try to preserve some classical logic, especially the law of excluded middle, in the face of problems of vagueness. More drastic views, like treating vagueness as irrelevant to logic, or the epistemic view, do better. |
| 9059 | The semantics of supervaluation (e.g. disjunction and quantification) is not classical [Keefe/Smith] |
| Full Idea: The semantics of supervaluational views is not classical. A disjunction can be true without either of its disjuncts being true, and an existential quantification can be true without any of its substitution instances being true. | |
| From: R Keefe / P Smith (Intro: Theories of Vagueness [1997], §3) | |
| A reaction: There is a vaguely plausible story here (either red or orange, but not definitely one nor tother; there exists an x, but which x it is is undecidable), but I think I will vote for this all being very very wrong. |
| 9060 | Supervaluation misunderstands vagueness, treating it as a failure to make things precise [Keefe/Smith] |
| Full Idea: Why should we think vague language is explained away by how things would be if it were made precise? Supervaluationism misrepresents vague expressions, as vague only because we have not bothered to make them precise. | |
| From: R Keefe / P Smith (Intro: Theories of Vagueness [1997], §3) | |
| A reaction: The theory still leaves a gap where vagueness is ineradicable, so the charge doesn't seem quite fair. Logicians always yearn for precision, but common speech enjoys wallowing in a sea of easy-going vagueness, which works fine. |
| 9050 | A third truth-value at borderlines might be 'indeterminate', or a value somewhere between 0 and 1 [Keefe/Smith] |
| Full Idea: One approach to predications in borderline cases is to say that they have a third truth value - 'neutral', 'indeterminate' or 'indefinite', leading to a three-valued logic. Or a degree theory, such as fuzzy logic, with infinite values between 0 and 1. | |
| From: R Keefe / P Smith (Intro: Theories of Vagueness [1997], §1) | |
| A reaction: This looks more like a strategy for computer programmers than for metaphysicians, as it doesn't seem to solve the difficulty of things to which no one can quite assign any value at all. Sometimes you can't be sure if an entity is vague. |
| 9061 | People can't be placed in a precise order according to how 'nice' they are [Keefe/Smith] |
| Full Idea: There is no complete ordering of people by niceness, and two people could be both fairly nice, nice to intermediate degrees, while there is no fact of the matter about who is the nicer. | |
| From: R Keefe / P Smith (Intro: Theories of Vagueness [1997], §4) | |
| A reaction: This is a difficulty if you are trying to decide vague predicates by awarding them degrees of truth. Attempts to place a precise value on 'nice' seem to miss the point, even more than utilitarian attempts to score happiness. |
| 9062 | If truth-values for vagueness range from 0 to 1, there must be someone who is 'completely tall' [Keefe/Smith] |
| Full Idea: Many-valued theories still seem to have a sharp boundary between sentences taking truth-value 1 and those taking value less than 1. So there is a last man in our sorites series who counts as 'completely tall'. | |
| From: R Keefe / P Smith (Intro: Theories of Vagueness [1997], §4) | |
| A reaction: Lovely. Completely nice, totally red, perfectly childlike, an utter mountain, one hundred per cent amused. The enterprise seems to have the same implausibility found in Bayesian approaches to assessing evidence. |
| 9063 | How do we decide if my coat is red to degree 0.322 or 0.321? [Keefe/Smith] |
| Full Idea: What could determine which is the correct function, settling that my coat is red to degree 0.322 rather than 0.321? | |
| From: R Keefe / P Smith (Intro: Theories of Vagueness [1997], §4) | |
| A reaction: It is not just the uncertainty of placing the coat on the scale. The two ends of the scale have all the indeterminacy of being red rather than orange (or, indeed, pink). You are struggling to find a spot on the ruler, when the ruler is placed vaguely. |
| 9045 | Vague predicates involve uncertain properties, uncertain objects, and paradoxes of gradual change [Keefe/Smith] |
| Full Idea: Three interrelated features of vague predicates such as 'tall', 'red', 'heap', 'child' are that they have borderline cases (application is uncertain), they lack well-defined extensions (objects are uncertain), and they're susceptible to sorites paradoxes. | |
| From: R Keefe / P Smith (Intro: Theories of Vagueness [1997], §1) | |
| A reaction: The issue will partly depend on what you think an object is: choose from bundles of properties, total denial, essential substance, or featureless substance with properties. The fungal infection of vagueness could creep in at any point, even the words. |
| 9047 | Many vague predicates are multi-dimensional; 'big' involves height and volume; heaps include arrangement [Keefe/Smith] |
| Full Idea: Many vague predicates are multi-dimensional. 'Big' of people depends on both height and volume; 'nice' does not even have clear dimensions; whether something is a 'heap' depends both the number of grains and their arrangement. | |
| From: R Keefe / P Smith (Intro: Theories of Vagueness [1997], §1) | |
| A reaction: Anyone who was hoping for a nice tidy theory for this problem should abandon hope at this point. Huge numbers of philosophical problems can be simplified by asking 'what exactly do you mean here?' (e.g. tall or bulky?). |
| 9053 | If there is a precise borderline area, that is not a case of vagueness [Keefe/Smith] |
| Full Idea: If a predicate G has a sharply-bounded set of cases falling in between the positive and negative, this shows that merely having borderline cases is not sufficient for vagueness. | |
| From: R Keefe / P Smith (Intro: Theories of Vagueness [1997], §1) | |
| A reaction: Thus you might have 'pass', 'fail' and 'take the test again'. But there seem to be two cases in the border area: will decide later, and decision seems impossible. And the sharp boundaries may be quite arbitrary. |
| 19061 | An explanation is often a deduction, but that may well beg the question [Dummett] |
| Full Idea: An explanation is often a deductive argument, with the fact needing explaining as its conclusion. ...But the conclusion is usually given in advance, and we may only believe the premisses because they plausibly explain the conclusion. | |
| From: Michael Dummett (The Justification of Deduction [1973], p.296) | |
| A reaction: [compressed (Dummett's wordy prose cries out for it!)] I suppose this works better in mathematics, which is central to Dummett's interests. In the real world the puzzle is not usually logically implied by its explanation. |
| 20757 | The powerful self behind your thoughts and feelings is your body [Nietzsche] |
| Full Idea: Behind your thoughts and feelings stands a powerful commander, an unknown wise man - he is called a self. He lives in your body; he is your body. | |
| From: Friedrich Nietzsche (Thus Spake Zarathustra [1884], I.4), quoted by Kevin Aho - Existentialism: an introduction 5 'Creature' | |
| A reaction: I find Nietzsche's view of the self very congenial, though I tend to see the self as certain central functions of the brain. The brain is enmeshed in the body (as in the location of pains). |
| 18289 | Forget the word 'I'; 'I' is performed by the intelligence of your body [Nietzsche] |
| Full Idea: You say 'I' and you are proud of this word. But greater than this - although you will not believe in it - is your body and its great intelligence, which does not say 'I' but performs 'I'. | |
| From: Friedrich Nietzsche (Thus Spake Zarathustra [1884], 1.05) | |
| A reaction: I'm not sure if I understand this, but I offer it as a candidate for the most profound idea ever articulated about personal identity. |
| 19064 | Holism is not a theory of meaning; it is the denial that a theory of meaning is possible [Dummett] |
| Full Idea: In the sense of giving a model for the content of a sentence, its representative power, holism is not a theory of meaning; it is the denial that a theory of meaning is possible. | |
| From: Michael Dummett (The Justification of Deduction [1973], p.309) | |
| A reaction: This will obviously be because sentences just don't have meaning in isolation, so their meaning can't be given in terms of the sentences. |
| 18299 | The will is constantly frustrated by the past [Nietzsche] |
| Full Idea: Powerless against that which has been done, the will is an angry spectator of all things past. The will cannot will backwards; that it cannot break time and time's desire - that is the will's most lonely affliction. | |
| From: Friedrich Nietzsche (Thus Spake Zarathustra [1884], 2.20) |
| 18297 | We created meanings, to maintain ourselves [Nietzsche] |
| Full Idea: Man first implanted values into things to maintain himself - he first created the meaning of things, a human meaning! | |
| From: Friedrich Nietzsche (Thus Spake Zarathustra [1884], 1.16) | |
| A reaction: It is certainly hard to see anything resembling values or meaning in the cosmos, if you remove the human beings. We should expect an evolutionary grounding in their explanation. |
| 18293 | The noble man wants new virtues; the good man preserves what is old [Nietzsche] |
| Full Idea: The noble man wants to create new things and a new virtue. The good man wants the old things and that the old things shall be preserved. | |
| From: Friedrich Nietzsche (Thus Spake Zarathustra [1884], 1.09) | |
| A reaction: There is a limit to how many plausible virtues the noble men can come up with. We may already have run out. Are we going to have to re-run the Iliad? |
| 18301 | We only really love children and work [Nietzsche] |
| Full Idea: One loves from the very heart only one's child and one's work. | |
| From: Friedrich Nietzsche (Thus Spake Zarathustra [1884], 3.03) | |
| A reaction: Very Nietzchean (and masculine?) to cite one's work. Rachmaninov said he was 85% musician and 15% human being, so I guess he loved music from the very heart. |
| 18307 | I want my work, not happiness! [Nietzsche] |
| Full Idea: Do I aspire after happiness? I aspire after my work! | |
| From: Friedrich Nietzsche (Thus Spake Zarathustra [1884], 4.20) | |
| A reaction: I empathise with aspiring to do something, rather than be something. But what do we wish for our children? Happiness first, then achievement? |
| 18291 | Virtues can destroy one another, through jealousy [Nietzsche] |
| Full Idea: Every virtue is jealous of the others, and jealousy is a terrible thing. Even virtues can be destroyed through jealousy. | |
| From: Friedrich Nietzsche (Thus Spake Zarathustra [1884], 1.07) | |
| A reaction: How much more subtle and plausible than the picture of accumulating virtues, like medals! Zarathustra says it is best to have just one virtue. |
| 18287 | People now find both wealth and poverty too much of a burden [Nietzsche] |
| Full Idea: Nobody grows rich or poor any more: both are too much of a burden. | |
| From: Friedrich Nietzsche (Thus Spake Zarathustra [1884], 1.01) | |
| A reaction: True. Most people I know are just puzzled by people who actually seem to want to be extremely wealthy. |
| 18295 | If you want friends, you must be a fighter [Nietzsche] |
| Full Idea: If you want a friend, you must be willing to wage war for him: and to wage war, you must be capable of being an enemy. | |
| From: Friedrich Nietzsche (Thus Spake Zarathustra [1884], 1.15) |
| 18286 | The greatest experience possible is contempt for your own happiness, reason and virtue [Nietzsche] |
| Full Idea: What is the greatest thing you can experience? It is the hour of the great contempt. The hour in which even your happiness grows loathsome to you, and your reason and your virtue also. | |
| From: Friedrich Nietzsche (Thus Spake Zarathustra [1884], 1.01) | |
| A reaction: This would be a transient state for Nietzsche, in which you realise the hollowness of those traditional ideas, and begin to seek something else. |
| 18296 | An enduring people needs its own individual values [Nietzsche] |
| Full Idea: No people could live without evaluating; but if it wishes to maintain itself it must not evaluate as its neighbour evaluates. | |
| From: Friedrich Nietzsche (Thus Spake Zarathustra [1884], 1.16) | |
| A reaction: Political philosophers say plenty about a 'people', but little about what unifies them, or about what keeps one people distinct from another. Most people's are proud of their local values. |
| 18294 | The state coldly claims that it is the people, but that is a lie [Nietzsche] |
| Full Idea: The state is the coldest of all cold monsters. Coldly it lies, too; and this lie creeps from its mouth: 'I, the state, am the people'. It is a lie! | |
| From: Friedrich Nietzsche (Thus Spake Zarathustra [1884], 1.12) | |
| A reaction: This strikes me as just as true even after everyone gets the vote. Rulers can't help gradually forgetting about the people. |
| 18304 | Saints want to live as they desire, or not to live at all [Nietzsche] |
| Full Idea: 'To live as I desire to live or not to live at all': that is what I want, that is what the most saintly man wants. | |
| From: Friedrich Nietzsche (Thus Spake Zarathustra [1884], 4.09) | |
| A reaction: [spoken by Zarathustra] |
| 18300 | Whenever we have seen suffering, we have wanted the revenge of punishment [Nietzsche] |
| Full Idea: The spirit of revenge: my friends, that, up to now, has been mankind's chief concern; and where there was suffering, there was always supposed to be punishment. | |
| From: Friedrich Nietzsche (Thus Spake Zarathustra [1884], 2.20) |
| 18302 | Man and woman are deeply strange to one another! [Nietzsche] |
| Full Idea: Who has fully conceived how strange man and woman are to one another! | |
| From: Friedrich Nietzsche (Thus Spake Zarathustra [1884], 3.10.2) |
| 18292 | I can only believe in a God who can dance [Nietzsche] |
| Full Idea: I should believe only in a God who understood how to dance. | |
| From: Friedrich Nietzsche (Thus Spake Zarathustra [1884], 1.08) |
| 18298 | Not being a god is insupportable, so there are no gods! [Nietzsche] |
| Full Idea: If there were gods, how could I endure not to be a god! Therefore there are no gods. ...For what would there to be create if gods - existed! | |
| From: Friedrich Nietzsche (Thus Spake Zarathustra [1884], 2.02) | |
| A reaction: [Zarathustra says this, not Nietzsche!] |
| 18288 | Heaven was invented by the sick and the dying [Nietzsche] |
| Full Idea: It was the sick and dying who despised the body and the earth and invented the things of heaven and the redeeming drops of blood. | |
| From: Friedrich Nietzsche (Thus Spake Zarathustra [1884], 1.04) |
| 18306 | We don't want heaven; now that we are men, we want the kingdom of earth [Nietzsche] |
| Full Idea: We certainly do not want to enter into the kingdom of heaven: we have become men, so we want the kingdom of earth. | |
| From: Friedrich Nietzsche (Thus Spake Zarathustra [1884], 4.18.2) |