47 ideas
7493 | Let us reason together, saith the Lord [Isaiah] |
Full Idea: Come now, and let us reason together, saith the Lord. | |
From: Isaiah (23: Book of Isaiah [c.680 BCE], 01.18) | |
A reaction: A verse which not only offers Biblical support for philosophy, but would also seem to be a challenge to Christian fideists. |
16943 | Philosophy is continuous with science, and has no external vantage point [Quine] |
Full Idea: I see philosophy not as an a priori propaedeutic or groundwork for science, but as continuous with science. I see philosophy and science as in the same boat. …There is no external vantage point, no first philosophy. | |
From: Willard Quine (Natural Kinds [1969], p.126) | |
A reaction: Philosophy is generalisation. Science holds the upper hand, because it settles the subject-matter to be generalised. |
9023 | If you say that a contradiction is true, you change the meaning of 'not', and so change the subject [Quine] |
Full Idea: Those who regard the conjunction p.not-p as true think they are talking about negation, 'not', but this ceases to be recognisable as negation. The deviant logician's predicament is when he tries to deny the doctrine he only changes the subject. | |
From: Willard Quine (Philosophy of Logic [1970], Ch.6) | |
A reaction: The charge of 'changing the subject' has become a classic move in modern discussions of non-standard logics. It is an important idea in discussions of arguments, and is found in Kant's account of the Ontological Argument. |
9012 | Talk of 'truth' when sentences are mentioned; it reminds us that reality is the point of sentences [Quine] |
Full Idea: The truth predicate has its utility in places where we are compelled to mention sentences. It then serves to point through the sentence to the reality; it serves as a reminder that though sentences are mentioned, reality is still the whole point. | |
From: Willard Quine (Philosophy of Logic [1970], Ch.1) | |
A reaction: A sensible interpretation of the Tarskian account of truth as disquotation. Quine neatly combines a common sense correspondence with a sophisticated logicians view of the role of truth. So what does "I want the truth here" mean? |
9011 | Truth is redundant for single sentences; we do better to simply speak the sentence [Quine] |
Full Idea: Rather than speak of truth, we do better simply to say the sentence and so speak not about language but about the world. Of singly given sentences, the perfect theory of truth is the 'disappearance theory of truth' (Sellars). | |
From: Willard Quine (Philosophy of Logic [1970], Ch.1) | |
A reaction: Quine defends truth as the crucial link between language and reality, but only for large groups of sentences. If someone accuses you of lying or being incorrect, you can respond by repeating your sentence in a firmer tone of voice. |
9013 | We can eliminate 'or' from our basic theory, by paraphrasing 'p or q' as 'not(not-p and not-q)' [Quine] |
Full Idea: The construction of 'alternation' (using 'or') is useful in practice, but superfluous in theory. It can be paraphrased using only negation and conjunction. We say that 'p or q' is paraphrased as 'not(not-p and not-q)'. | |
From: Willard Quine (Philosophy of Logic [1970], Ch.2) | |
A reaction: Quine treats 'not' and 'and' as the axiomatic logical connectives, and builds the others from those, presumably because that is the smallest number he could get it down to. I quite like it, because it seems to mesh with basic thought procedures. |
9020 | My logical grammar has sentences by predication, then negation, conjunction, and existential quantification [Quine] |
Full Idea: We chose a standard grammar in which the simple sentences are got by predication, and all further sentences are generated from these by negation, conjunction, and existential quantification. | |
From: Willard Quine (Philosophy of Logic [1970], Ch.3) | |
A reaction: It is interesting that we 'choose' our logic, apparently guided by an imperative to achieve minimal ontology. Of these basic ingredients, negation and predication are the more mysterious, especially the latter. Quine is a bit of an 'ostrich' about that. |
9028 | Maybe logical truth reflects reality, but in different ways in different languages [Quine] |
Full Idea: Perhaps the logical truths owe their truth to certain traits of reality which are reflected in one way by the grammar of our language, in another way by the grammar of another language, and in a third way by the grammar and lexicon of a third language. | |
From: Willard Quine (Philosophy of Logic [1970], Ch.7) | |
A reaction: This explains Quine's subsequent interest in translation, and the interest of his pupil Davidson in charity, and whether there could actually be rival conceptual schemes. I like the link between logical truths and reality, which follows Russell. |
10014 | Quine rejects second-order logic, saying that predicates refer to multiple objects [Quine, by Hodes] |
Full Idea: Quine is unwilling to suppose second-order logic intelligible. He holds to Mill's account of the referential role of a predicate: it multiply denotes any and all objects to which it applies, and there is no need for a further 'predicative' entity. | |
From: report of Willard Quine (Philosophy of Logic [1970]) by Harold Hodes - Logicism and Ontological Commits. of Arithmetic p.130 | |
A reaction: If we assume that 'quantifying over' something is a commitment to its existence, then I think I am with Quine, because you end up with a massive commitment to universals, which I prefer to avoid. |
10828 | Quantifying over predicates is treating them as names of entities [Quine] |
Full Idea: To put the predicate letter 'F' in a quantifier is to treat predicate position suddenly as name position, and hence to treat predicates as names of entities of some sort. | |
From: Willard Quine (Philosophy of Logic [1970], Ch.5) | |
A reaction: It is tricky to distinguish quantifying over predicates in a first-order way (by reifying them), and in a second-order way (where it is not clear whether you are quantifying over a property or a unified set of things. |
9024 | Excluded middle has three different definitions [Quine] |
Full Idea: The law of excluded middle, or 'tertium non datur', may be pictured variously as 1) Every closed sentence is true or false; or 2) Every closed sentence or its negation is true; or 3) Every closed sentence is true or not true. | |
From: Willard Quine (Philosophy of Logic [1970], Ch.6) | |
A reaction: Unlike many top philosophers, Quine thinks clearly about such things. 1) is the classical bivalent reading of excluded middle; 2) is the purely syntactic version; 3) leaves open how we interpret the 'not-true' option. |
10012 | Quantification theory can still be proved complete if we add identity [Quine] |
Full Idea: Complete proof procedures are available not only for quantification theory, but for quantification theory and identity together. Gödel showed that the theory is still complete if we add self-identity and the indiscernability of identicals. | |
From: Willard Quine (Philosophy of Logic [1970], Ch.5) | |
A reaction: Hence one talks of first-order logic 'with identity', even though, as Quine observes, it is unclear whether identity is actually a logical or a mathematical notion. |
9016 | Names are not essential, because naming can be turned into predication [Quine] |
Full Idea: Names are convenient but redundant, because Fa is equivalent to (an x)(a=x,Fx), so a need only occur in the context a=, but this can be rendered as a simple predicate A, so that Fa gives way to (an x)(Ax.Fx). | |
From: Willard Quine (Philosophy of Logic [1970], Ch.2) | |
A reaction: In eliminating names from analysis, Quine takes Russell's strategy a step further. It is probably this which provoked Kripke into going right back to Mill's view of names as basic labels. The name/description boundary is blurred. Mr Gradgrind. |
9015 | Universal quantification is widespread, but it is definable in terms of existential quantification [Quine] |
Full Idea: Universal quantification is prominent in logical practice but superfluous in theory, since (for all x)Fx obviously amounts to not(exists an x)not-Fx. | |
From: Willard Quine (Philosophy of Logic [1970], Ch.2) | |
A reaction: The equivalence between these two works both ways, some you could take the universal quantifier as primitive instead, which would make general truths prior to particular ones. Is there something deep at stake here? |
9025 | You can't base quantification on substituting names for variables, if the irrationals cannot all be named [Quine] |
Full Idea: A customary argument against quantification based on substitution of names for variables refers to the theorem of set theory that irrational numbers cannot all be assigned integers. Although the integers can all be named, the irrationals therefore can't. | |
From: Willard Quine (Philosophy of Logic [1970], Ch.6) | |
A reaction: [He names Ruth Marcus as a source of substitutional quantification] This sounds like more than a mere 'argument' against substitutional quantification, but an actual disproof. Or maybe you just can't quantify once you run out of names. |
9026 | Some quantifications could be false substitutionally and true objectually, because of nameless objects [Quine] |
Full Idea: An existential quantification could turn out false when substitutionally construed and true when objectually construed, because of there being objects of the purported kind but only nameless ones. | |
From: Willard Quine (Philosophy of Logic [1970], Ch.6) | |
A reaction: (Cf. Idea 9025) Some irrational numbers were his candidates for nameless objects, but as decimals they are infinite in length which seems unfair. I don't take even pi or root-2 to be objects in nature, so not naming irrationals doesn't bother me. |
10705 | Putting a predicate letter in a quantifier is to make it the name of an entity [Quine] |
Full Idea: To put the predicate letter 'F' in a quantifier is to treat predicate positions suddenly as name positions, and hence to treat predicates as names of entities of some sort. | |
From: Willard Quine (Philosophy of Logic [1970], Ch.5) | |
A reaction: Quine's famous objection to second-order logic. But Quine then struggles to give an account of predicates and properties, and hence is accused by Armstrong of being an 'ostrich'. Boolos 1975 also attacks Quine here. |
9027 | A sentence is logically true if all sentences with that grammatical structure are true [Quine] |
Full Idea: A sentence is logically true if all sentences with that grammatical structure are true. | |
From: Willard Quine (Philosophy of Logic [1970], Ch.7) | |
A reaction: Quine spends some time on the tricky question of deciding which parts of a sentence are grammatical structure ('syncategorematic'), and which parts are what he calls 'lexicon'. I bet there is a Quinean argument which blurs the boundary. |
16949 | Klein summarised geometry as grouped together by transformations [Quine] |
Full Idea: Felix Klein's so-called 'Erlangerprogramm' in geometry involved characterizing the various branches of geometry by what transformations were irrelevant to each. | |
From: Willard Quine (Natural Kinds [1969], p.137) |
16939 | Mass terms just concern spread, but other terms involve both spread and individuation [Quine] |
Full Idea: 'Yellow' and 'water' are mass terms, concerned only with spread; 'apple' and 'square' are terms of divided reference, concerned with both spread and individuation. | |
From: Willard Quine (Natural Kinds [1969], p.124) | |
A reaction: Would you like some apple? Pass me that water. It is helpful to see that it is a requirement of 'individuation' that is missing from terms for stuff. |
9017 | Predicates are not names; predicates are the other parties to predication [Quine] |
Full Idea: Predicates are not names; predicates are the other parties to predication. | |
From: Willard Quine (Philosophy of Logic [1970], Ch.2) | |
A reaction: Does a wife only exist as party to a marriage? There's something missing here. We are taking predication to be primitive, but we then seem to single out one part of the process - the object - while ignoring the remainder. What are Quinean objects? |
16948 | Once we know the mechanism of a disposition, we can eliminate 'similarity' [Quine] |
Full Idea: Once we can legitimize a disposition term by defining the relevant similarity standard, we are apt to know the mechanism of the disposition, and so by-pass the similarity. | |
From: Willard Quine (Natural Kinds [1969], p.135) | |
A reaction: I love mechanisms, but can we characterise mechanisms without mentioning powers and dispositions? Quine's dream is to eliminate 'similarity'. |
16945 | We judge things to be soluble if they are the same kind as, or similar to, things that do dissolve [Quine] |
Full Idea: Intuitively, what qualifies a thing as soluble though it never gets into water is that it is of the same kind as the things that actually did or will dissolve; it is similar to them. | |
From: Willard Quine (Natural Kinds [1969], p.130) | |
A reaction: If you can judge that the similar things 'will' dissolve, you can cut to the chase and judge that this thing will dissolve. |
9018 | A physical object is the four-dimensional material content of a portion of space-time [Quine] |
Full Idea: We might think of a physical object as simply the whole four-dimensional material content, however sporadic and heterogeneous, of some portion of space-time. If it is firm and coherent internally, we call it a body. | |
From: Willard Quine (Philosophy of Logic [1970], Ch.2) | |
A reaction: An early articulation of one of the two standard views of objects in recent philosophy. I think I prefer the Quinean view, but I am still looking into that one... |
9019 | Four-d objects helps predication of what no longer exists, and quantification over items from different times [Quine] |
Full Idea: The four-dimensional view of objects aids relativity, and the grammar of tenses, but in logic it makes sense of applying a predicate to something that no longer exists, or of quantifying over objects that never coexisted at any one time. | |
From: Willard Quine (Philosophy of Logic [1970], Ch.2) | |
A reaction: Since you can predicate of or quantify over hypothetical or fictional objects ('Hamlet is gloomy', 'phlogiston explained fire quite well', 'peace and quiet would be nice') I don't see the necessity for this bold ontological commitment, on these grounds. |
9014 | Some conditionals can be explained just by negation and conjunction: not(p and not-q) [Quine] |
Full Idea: Often the purpose of a conditional, 'if p, q', can be served simply by negation and conjunction: not(p and not-q), the so-called 'material conditional'. | |
From: Willard Quine (Philosophy of Logic [1970], Ch.2) | |
A reaction: Logicians love the neatness of that, but get into trouble elsewhere with conditionals, particularly over the implications of not-p. |
16944 | Science is common sense, with a sophisticated method [Quine] |
Full Idea: Sciences differ from common sense only in the degree of methodological sophistication. | |
From: Willard Quine (Natural Kinds [1969], p.129) | |
A reaction: Science is normal thinking about the world, but it is teamwork, with the bar set very high. |
16941 | Induction relies on similar effects following from each cause [Quine] |
Full Idea: Induction expresses our hopes that similar causes will have similar effects. | |
From: Willard Quine (Natural Kinds [1969], p.125) | |
A reaction: Some top philosophers are also top teachers, and Quine was one of them, in his writings. He boils it down for the layman. Once again, he is pointing to the fundamental role of the similarity relation. |
16940 | Induction is just more of the same: animal expectations [Quine] |
Full Idea: Induction is essentially only more of the same: animal expectation or habit formation. | |
From: Willard Quine (Natural Kinds [1969], p.125) | |
A reaction: My working definition of induction is 'learning from experience', but that doesn't disagree with Quine. Lipton has a richer account of different types of induction. Quine's point is that it rests on resemblance. |
16933 | Grue is a puzzle because the notions of similarity and kind are dubious in science [Quine] |
Full Idea: What makes Goodman's example a puzzle is the dubious scientific standing of a general notion of similarity, or of kind. | |
From: Willard Quine (Natural Kinds [1969], p.116) | |
A reaction: Illuminating. It might be best expressed as revealing a problem with sortal terms, as employed by Geach, or by Wiggins. Grue is a bit silly, but sortals are subject to convention and culture. 'Natural' properties seem needed. |
16934 | General terms depend on similarities among things [Quine] |
Full Idea: The usual general term, whether a common noun or a verb or an adjective, owes its generality to some resemblance among the things referred to. | |
From: Willard Quine (Natural Kinds [1969], p.116) | |
A reaction: Quine has a nice analysis of the basic role of similarity in a huge amount of supposedly strict scientific thought. |
16938 | To learn yellow by observation, must we be told to look at the colour? [Quine] |
Full Idea: According to the 'respects' view, our learning of yellow by ostension would have depended on our first having been told or somehow apprised that it was going to be a question of color. | |
From: Willard Quine (Natural Kinds [1969], p.122) | |
A reaction: Quine suggests there is just one notion of similarity, and respects can be 'abstracted' afterwards. Even the ontologically ruthless Quine admits psychological abstraction! |
8486 | Standards of similarity are innate, and the spacing of qualities such as colours can be mapped [Quine] |
Full Idea: A standard of similarity is in some sense innate. The spacing of qualities (such as red, pink and blue) can be explored and mapped in the laboratory by experiments. They are needed for all learning. | |
From: Willard Quine (Natural Kinds [1969], p.123) | |
A reaction: This reasserts Hume's original point in more scientific terms. It is one of the undeniable facts about our perceptions of qualities and properties, no matter how platonist your view of universals may be. |
16947 | Similarity is just interchangeability in the cosmic machine [Quine] |
Full Idea: Things are similar to the extent that they are interchangeable parts of the cosmic machine. | |
From: Willard Quine (Natural Kinds [1969], p.134) | |
A reaction: This is a major idea for Quine, because it is a means to gradually eliminate the fuzzy ideas of 'resemblance' or 'similarity' or 'natural kind' from science. I love it! Two tigers are same insofar as they are substitutable. |
9009 | Single words are strongly synonymous if their interchange preserves truth [Quine] |
Full Idea: We can define, it would seem, a strong synonymy relation for single words by them being interchangeable salva veritate. | |
From: Willard Quine (Philosophy of Logic [1970], Ch.1) | |
A reaction: This is a first step in Quine's rejection of synonymous sentences. He goes on to raise the problem of renate/cordate. Presumably any two word types can have different connotations, and hence not always be interchangeable - in poetry, for example. |
16932 | Projectible predicates can be universalised about the kind to which they refer [Quine] |
Full Idea: 'Projectible' predicates are predicates F and G whose shared instances all do count, for whatever reason, towards confirmation of 'All F are G'. ….A projectible predicate is one that is true of all and only the things of a kind. | |
From: Willard Quine (Natural Kinds [1969], p.115-6) | |
A reaction: Both Quine and Goodman are infuriatingly brief about the introduction of this concept. 'Red' is true of all ripe tomatoes, but not 'only' of them. Hardly any predicates are true only of one kind. Is that a scholastic 'proprium'? |
9007 | It makes no sense to say that two sentences express the same proposition [Quine] |
Full Idea: My objection to propositions is not parsimony, or disapproval of abstract entities, ..but that propositions induce a relation of synonymy or equivalence between sentences (expressing the same proposition), and this makes no objective sense. | |
From: Willard Quine (Philosophy of Logic [1970], Ch.1) | |
A reaction: Personally I think propositions are unavoidable when you try to connect language to activities of the brain, and also when you consider animal thought. And also when you introspect about your own language processes. Mr Quine, he wrong. |
9008 | There is no rule for separating the information from other features of sentences [Quine] |
Full Idea: There is no evident rule for separating the information from the stylistic or other immaterial features of the sentences. | |
From: Willard Quine (Philosophy of Logic [1970], Ch.1) | |
A reaction: There is no rule for deciding precisely when night falls, so I don't believe in night. I take a proposition, prima facie, as an answer to the question 'What exactly do you mean by that remark?' How do you extract logical form from sentences? |
9010 | We can abandon propositions, and just talk of sentences and equivalence [Quine] |
Full Idea: Why not just talk of sentences and equivalence and let the propositions go? Propositions have been projected as shadows of sentences, but at best they will give us nothing the sentences will not give. | |
From: Willard Quine (Philosophy of Logic [1970], Ch.1) | |
A reaction: I don't understand how you decide that two sentences are equivalent. 'There's someone in that wood'; 'yes, there's a person amongst those trees'. Identical truth-conditions. We can formulate a non-linguistic fact about those truth-conditions. |
9021 | A good way of explaining an expression is saying what conditions make its contexts true [Quine] |
Full Idea: A reasonable way of explaining an expression is by saying what conditions make its various contexts true. | |
From: Willard Quine (Philosophy of Logic [1970], Ch.3) | |
A reaction: I like the circumspect phrasing of this, which carefully avoids any entities such as 'meanings' or 'truth conditions'. Maybe the whole core of philosophy of language should shift from theories of meaning to just trying to 'explain' sentences. |
7375 | Quine probably regrets natural kinds now being treated as essences [Quine, by Dennett] |
Full Idea: The concept of natural kinds was reintroduced by Quine, who may now regret the way it has become a stand-in for the dubious but covertly popular concept of essences. | |
From: report of Willard Quine (Natural Kinds [1969]) by Daniel C. Dennett - Consciousness Explained 12.2 n2 | |
A reaction: He is right that Quine would regret it, and he is right that we can't assume that there are necessary essences just because there seem to be stable natural kinds, but personally I am an essentialist, so I'm not that bothered. |
16935 | If similarity has no degrees, kinds cannot be contained within one another [Quine] |
Full Idea: If similarity has no degrees there is no containing of kinds within broader kinds. If colored things are a kind, they are similar, but red things are too narrow for a kind. If red things are a kind, colored things are not similar, and it's too broad. | |
From: Willard Quine (Natural Kinds [1969], p.118) | |
A reaction: [compressed] I'm on Quine's side with this. We glibly talk of 'kinds', but the criteria for sorting things into kinds seems to be a mess. Quine goes on to offer a better account than the (diadic, yes-no) one rejected here. |
16936 | Comparative similarity allows the kind 'colored' to contain the kind 'red' [Quine] |
Full Idea: With the triadic relation of comparative similarity, kinds can contain one another, as well as overlapping. Red and colored things can both count as kinds. Colored things all resemble one another, even though less than red things do. | |
From: Willard Quine (Natural Kinds [1969], p.119) | |
A reaction: [compressed] Quine claims that comparative similarity is necessary for kinds - that there be some 'foil' in a similarity - that A is more like C than B is. |
16937 | You can't base kinds just on resemblance, because chains of resemblance are a muddle [Quine] |
Full Idea: If kinds are based on similarity, this has the Imperfect Community problem. Red round, red wooden and round wooden things all resemble one another somehow. There may be nothing outside the set resembling them, so it meets the definition of kind. | |
From: Willard Quine (Natural Kinds [1969], p.120) | |
A reaction: [ref. to Goodman 'Structure' 2nd 163- , which attacks Carnap on this] This suggests an invocation of Wittgenstein's family resemblance, which won't be much help for natural kinds. |
16942 | It is hard to see how regularities could be explained [Quine] |
Full Idea: Why there have been regularities is an obscure question, for it is hard to see what would count as an answer. | |
From: Willard Quine (Natural Kinds [1969], p.126) | |
A reaction: This is the standard pessimism of the 20th century Humeans, but it strikes me as comparable to the pessimism about science found in Locke and Hume. Regularities are explained all the time by scientists, though the lowest level may be hopeless. |
7608 | The world is established, and cannot be moved [Isaiah] |
Full Idea: The world is also established, that it cannot be moved. | |
From: Isaiah (23: Book of Isaiah [c.680 BCE], 93.1) | |
A reaction: This verse caused big trouble for Galileo. The only reason I can think of for Isaiah to write this is that occasionally people were prone to panic, and worry that the Earth might suddenly and abruptly be moved. |
7343 | Beside me there is no God [Isaiah] |
Full Idea: I am the first, and I am the last; and beside me there is no God. | |
From: Isaiah (23: Book of Isaiah [c.680 BCE], 44.06) | |
A reaction: This seems to be the first clear statement (c. 680 BCE) of monotheism, certainly preceding any Greek views on the subject (cf. Idea 2629,Idea 7347). It is not just an arrogant assertion by the jews, but a humble sacrifice, donating their god to humanity. |