54 ideas
| 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. |
| 15879 | The Square of Opposition has two contradictory pairs, one contrary pair, and one sub-contrary pair [Harré] |
| Full Idea: Square of Opposition: 'all A are B' and 'no A are B' are contraries; 'some A are B' and 'some A are not B' are sub-contraries; the pairs 'all A are B'/'some A are B' and 'no A are B'/'some A are B' are contradictories. | |
| From: Rom Harré (Laws of Nature [1993], 3) | |
| A reaction: [the reader may construct his own diagram from this description!] The contraries are at the extremes of contradiction, but the sub-contraries are actual compatible. You could add possible worlds to this picture. |
| 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? |
| 15891 | Traditional quantifiers combine ordinary language generality and ontology assumptions [Harré] |
| Full Idea: The generalising function and the ontological function of discourse are elided in the traditional quantifier. | |
| From: Rom Harré (Laws of Nature [1993], 5) | |
| A reaction: This simple point strikes me as helping enormously to disentangle the mess created by over-emphasis on formal logic in ontology, and especially in the Quinean concept of 'ontological commitment'. |
| 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. |
| 15878 | Some quantifiers, such as 'any', rule out any notion of order within their range [Harré] |
| Full Idea: The quantifier 'any' unambiguously rules out any presupposition of order in the members of the range of individuals quantified. | |
| From: Rom Harré (Laws of Nature [1993], 3) | |
| A reaction: He contrasts this with 'all', 'each' and 'every', which are ambiguous in this respect. |
| 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. |
| 15874 | Scientific properties are not observed qualities, but the dispositions which create them [Harré] |
| Full Idea: The properties of material things with which the sciences deal are not the qualities we observe them to have, but the dispositions of those things to engender the states and qualities we observe. | |
| From: Rom Harré (Laws of Nature [1993], 2) | |
| A reaction: I take this to be the correct use of the word 'qualities', so that properties are not qualities (in the way Heil would like). |
| 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? |
| 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. |
| 15884 | Laws of nature remain the same through any conditions, if the underlying mechanisms are unchanged [Harré] |
| Full Idea: A statement is a law of nature if it is true in all those worlds which differ only as to their initial conditions, that is in which the underlying mechanisms of nature are the same. | |
| From: Rom Harré (Laws of Nature [1993], 4) | |
| A reaction: Harré takes it that laws of nature have to be necessary, by definition. I like this way of expressing natural necessity, in terms of 'mechanisms' rather than of 'laws'. Where do the mechanisms get their necessity? |
| 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. |
| 15880 | In physical sciences particular observations are ordered, but in biology only the classes are ordered [Harré] |
| Full Idea: In the physical sciences the particular observations and experimental results are usually orderable, while in the biological sciences it is the classes of organism which are ordered, not the particular organisms. | |
| From: Rom Harré (Laws of Nature [1993], 3) | |
| A reaction: Harré is interesting on the role of ordering in science. Functions can be defined by an order. Maths feeds on orderings. Physics, he notes, focuses on things which vary together. |
| 15869 | Reports of experiments eliminate the experimenter, and present results as the behaviour of nature [Harré] |
| Full Idea: In accounts of experiments, by Faraday and others, the role of the guiding hand of the actual experimenter is written out in successive accounts. The effect is to display the phenomenon as a natural occurrence, existing independently of the experiments. | |
| From: Rom Harré (Laws of Nature [1993], 1) | |
| A reaction: He records three stages in Faraday's reports. The move from active to passive voice is obviously part of it. The claim of universality is thus implicit rather than explicit. |
| 15881 | We can save laws from counter-instances by treating the latter as analytic definitions [Harré] |
| Full Idea: When we come upon a counter-instance to a generalisation we can save the putative law, by treating it as potentially analytic and claiming it as a definition. ...Thus magnetism doesn't hold for phosphorus, so we say phosphorus is not a magnetic substance. | |
| From: Rom Harré (Laws of Nature [1993], 3) | |
| A reaction: He notes this as being particularly true when the laws concern the dispositions of substances, rather than patterns of events. |
| 15882 | Since there are three different dimensions for generalising laws, no one system of logic can cover them [Harré] |
| Full Idea: Since there are three different dimensions of generality into which every law of nature is generalised, there can be no one system of logic which will govern inference to or from every law of every kind. | |
| From: Rom Harré (Laws of Nature [1993], 3) | |
| A reaction: This is aimed at the covering-law approach, which actually aims to output observations as logical inferences from laws. Wrong. |
| 15888 | The grue problem shows that natural kinds are central to science [Harré] |
| Full Idea: The grue problem illustrates the enormous importance that the concept of a natural-kind plays in real science. | |
| From: Rom Harré (Laws of Nature [1993], 5) | |
| A reaction: The point is that we took emeralds to be a natural kind, but 'grue' proposes that they aren't, since stability is the hallmark of a natural kind. |
| 15887 | 'Grue' introduces a new causal hypothesis - that emeralds can change colour [Harré] |
| Full Idea: In introducing the predicate 'grue' we also introduce an additional causal hypothesis into our chemistry and physics; namely, that when observed grue emeralds change from blue to green. | |
| From: Rom Harré (Laws of Nature [1993], 5) | |
| A reaction: [The 'when observered' is a Harré addition] I hate 'grue'. Only people who think our predicates have very little to do with reality are impressed by it. Grue is a behaviour, not a colour. |
| 15889 | It is because ravens are birds that their species and their colour might be connected [Harré] |
| Full Idea: It is because ravens are birds that it makes sense to contemplate the possibility of a lawful relation between their species and their colour. | |
| From: Rom Harré (Laws of Nature [1993], 5) | |
| A reaction: Compare the 'laws' concerning leaf colour in autumn, and the 'laws' concerning packaging colour in supermarkets. Harré's underlying point is that raven colour concerns mechanism. |
| 15890 | Non-black non-ravens just aren't part of the presuppositions of 'all ravens are black' [Harré] |
| Full Idea: Non-black non-ravens have no role to play in assessing the plausibility of 'All ravens are black' because their existence is not among the existential presuppositions of that statement. | |
| From: Rom Harré (Laws of Nature [1993], 5) | |
| A reaction: [He cites Strawson for the 'presupposition' approach] |
| 15885 | The necessity of Newton's First Law derives from the nature of material things, not from a mechanism [Harré] |
| Full Idea: The 'must' of Newton's First Law is different. There is no deeper level relative to the processes described to give a mechanism which generates uniform motion. There is no such mechanism. ..It specifies what it is for something to be a material thing. | |
| From: Rom Harré (Laws of Nature [1993], 4) | |
| A reaction: Harré says the law can only exist as part of a network of other ideas. |
| 15868 | Idealisation idealises all of a thing's properties, but abstraction leaves some of them out [Harré] |
| Full Idea: An 'idealisation' preserves all the properties of the source but it possesses these properties in some ideal or perfect form. ...An 'abstraction', on the other hand, lacks certain features of its source. | |
| From: Rom Harré (Laws of Nature [1993], 1) | |
| A reaction: Yet another example in contemporary philosophy of a clear understanding of the sort of abstraction which Geach and others have poured scorn on. |
| 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. |
| 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. |
| 13304 | Learned men gain more in one day than others do in a lifetime [Posidonius] |
| Full Idea: In a single day there lies open to men of learning more than there ever does to the unenlightened in the longest of lifetimes. | |
| From: Posidonius (fragments/reports [c.95 BCE]), quoted by Seneca the Younger - Letters from a Stoic 078 | |
| A reaction: These remarks endorsing the infinite superiority of the educated to the uneducated seem to have been popular in late antiquity. It tends to be the religions which discourage great learning, especially in their emphasis on a single book. |
| 15886 | Science rests on the principle that nature is a hierarchy of natural kinds [Harré] |
| Full Idea: The animating principle behind the material and discursive practices of science is the thesis that nature exemplifies multiple hierarchies of natural kinds. | |
| From: Rom Harré (Laws of Nature [1993], 5) | |
| A reaction: I agree. I take it to be a brute fact that there seem to be lots of stable natural kinds, which are worth investigating as long as they stay stable. If they are unstable, there needs to be something stable to measure that by - or we give up. |
| 15864 | Classification is just as important as laws in natural science [Harré] |
| Full Idea: Classification systems, or taxonomies, are as important a part of the natural sciences as are the laws of nature. | |
| From: Rom Harré (Laws of Nature [1993], 1) | |
| A reaction: This illustrates how our view of science is radically shifted if we give biology equal prominence with physics. |
| 15865 | Newton's First Law cannot be demonstrated experimentally, as that needs absence of external forces [Harré] |
| Full Idea: We can never devise an experimental situation in which there are no external forces to act on a body. It follows that Newton's First Law could never be demonstrated by means of experiment or observation. | |
| From: Rom Harré (Laws of Nature [1993], 1) | |
| A reaction: It can't be wholly demonstrated, but certain observations conform to it, such as the movement of low friction bodies, or the movements of planetary bodies. |
| 15862 | Laws can come from data, from theory, from imagination and concepts, or from procedures [Harré] |
| Full Idea: Boyle's Law generalises a mass of messy data culled from an apparatus; Snell's Law is an experimentally derived law deducible from theory; Newton's First Law derives from concepts and thought experiments; Mendel's Law used an experimental procedure. | |
| From: Rom Harré (Laws of Nature [1993], 1) | |
| A reaction: Nice examples, especially since Boyle's and Newton's laws are divided by a huge gulf, and arrived at about the same time. On p.35 Harré says these come down to two: abstraction from experiment, and derivation from deep assumptions. |
| 15870 | Are laws of nature about events, or types and universals, or dispositions, or all three? [Harré] |
| Full Idea: What is Newton's First Law about? Is it about events? Is it about types or universals? Is it about dispositions? Or is it, in some peculiar way, about all three? | |
| From: Rom Harré (Laws of Nature [1993], 2) | |
| A reaction: If laws merely chart regularities, then I suppose they are about events (which exhibit the regular patterns). If laws explain, which would be nice, then they are only about universals if you are a platonist. Hence laws are about dispositions. |
| 15871 | Are laws about what has or might happen, or do they also cover all the possibilities? [Harré] |
| Full Idea: Is Newton's First Law about what has actually happened or is it about what might, or could possibly happen? Is it about the actual events and states of the world, or possible events and states? | |
| From: Rom Harré (Laws of Nature [1993], 2) | |
| A reaction: I presume the first sentence distinguishes between what 'might (well)' happen, and what 'could (just) possibly happen'. I take it for granted that laws predict the actual future. The question is are they true of situations which will never occur? |
| 15876 | Maybe laws of nature are just relations between properties? [Harré] |
| Full Idea: The idea of the Dretske-Armstrong-Tooley view is very simple: the laws of nature relate properties to properties. | |
| From: Rom Harré (Laws of Nature [1993], 2) | |
| A reaction: Presumably the relations are necessary ones. I don't see why we need to mention these wretched 'universals' in order to expound this theory. It sounds much more plausible if you just say a property is defined by the way it relates to other properties. |
| 15872 | Must laws of nature be universal, or could they be local? [Harré] |
| Full Idea: Is a law of nature about everything in the universe or just about a restricted group of things? | |
| From: Rom Harré (Laws of Nature [1993], 2) | |
| A reaction: I presume the answer is that while a law may only refer to a small group of things, the law would still have to apply if that group moved or spread or enlarged, so it would have to be universals. A laws confined to one time or place? Maybe. |
| 15860 | We take it that only necessary happenings could be laws [Harré] |
| Full Idea: We do not take laws to be recordings of what happens perchance or for the most part, but specifications of what happens necessarily | |
| From: Rom Harré (Laws of Nature [1993], 1) | |
| A reaction: This sounds like a plausible necessary condition for a law, but it may not be a sufficient one. Are trivial necessities laws? On this view if there are no necessities then there are no laws. |
| 15867 | Laws describe abstract idealisations, not the actual mess of nature [Harré] |
| Full Idea: The laws of nature are not simple descriptions of what can be seen to happen. They are descriptions of abstractions and idealisations from a somewhat messy reality. | |
| From: Rom Harré (Laws of Nature [1993], 1) | |
| A reaction: This view seems to have increasingly gripped modern philosophers, so that the old view of God decreeing a few simple equations to run the world has faded away. |
| 15892 | Laws of nature state necessary connections of things, events and properties, based on models of mechanisms [Harré] |
| Full Idea: A law of nature tells us what kinds of things, events and properties (all else being equal) go along with what. The 'must' of natural necessity has its place here because it is bound up with a model or analogy representing generative mechanisms. | |
| From: Rom Harré (Laws of Nature [1993], 5) | |
| A reaction: This is Harré's final page summary of laws. I agree with it. I would say that the laws are therefore descriptive, of the patterns of behaviour that arise when generative mechanisms meet. Maybe laws concern 'transformations'. |
| 15875 | In counterfactuals we keep substances constant, and imagine new situations for them [Harré] |
| Full Idea: In drawing 'countefactual' conclusions we can be thought imaginatively to vary the conditions under which the substance, set-up etc. is manipulated or stimulated, while maintaining constant our conception of the nature of the being in question. | |
| From: Rom Harré (Laws of Nature [1993], 2) | |
| A reaction: Presumably you could vary the substance and keep the situation fixed, but then the counterfactual seems to be 'about' something different. Either that or the 'situation' is a actually a set of substances to be tested. |
| 20820 | Time is an interval of motion, or the measure of speed [Posidonius, by Stobaeus] |
| Full Idea: Posidonius defined time thus: it is an interval of motion, or the measure of speed and slowness. | |
| From: report of Posidonius (fragments/reports [c.95 BCE]) by John Stobaeus - Anthology 1.08.42 | |
| A reaction: Hm. Can we define motion or speed without alluding to time? Looks like we have to define them as a conjoined pair, which means we cannot fully understand either of them. |