41 ideas
19740 | A very hungry man cannot choose between equidistant piles of food [Aristotle] |
Full Idea: The man who, though exceedingly hungry and thirsty, and both equally, yet being equidistant from food and drink, is therefore bound to stay where he is. | |
From: Aristotle (On the Heavens [c.336 BCE], 296b33) | |
A reaction: This is, of course, Buridan's famous Ass, but this quotation has the advantage of precedence, and also of being expressed in an original quotation (which does not exist for Buridan). |
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. |
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'. |
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. |
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). |
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? |
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. |
398 | Each thing that has a function is for the sake of that function [Aristotle] |
Full Idea: Each thing that has a function is for the sake of that function. | |
From: Aristotle (On the Heavens [c.336 BCE], 286a08) | |
A reaction: This is the central idea of Aristotle's Ethics. Did it originate with Plato, or Socrates, the young pupil Aristotle? I suspect the strong influence of Aristotle on later Plato. A major idea. Functions link the facts to life. |
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. |
394 | An unworn sandal is in vain, but nothing in nature is in vain [Aristotle] |
Full Idea: We say of a sandal which is not worn that it is in vain; God and nature, however, do nothing in vain. | |
From: Aristotle (On the Heavens [c.336 BCE], 271a33) |
396 | There has to be some goal, and not just movement to infinity [Aristotle] |
Full Idea: There has to be some goal, and not just movement to infinity. | |
From: Aristotle (On the Heavens [c.336 BCE], 277a26) |
16102 | Aether moves in circles and is imperishable; the four elements perish, and move in straight lines [Aristotle, by Gill,ML] |
Full Idea: For Aristotle, aether and the four sublunary elements obey different physical laws. Aether moves naturally in a circle and, unlike its lower counterparts, is not a source of perishability. The four sublunary elements move naturally in straight lines. | |
From: report of Aristotle (On the Heavens [c.336 BCE]) by Mary Louise Gill - Aristotle on Substance Ch.2 | |
A reaction: I think it is anachronistic for Gill to talk of 'obeying' and 'laws'. She should have said that they have different 'natures'. We can be amused by Greek errors, until we stare hard at the problems they were trying to solve. |
17463 | An element is what bodies are analysed into, and won't itself divide into something else [Aristotle] |
Full Idea: An element is a body into which other bodies may be analyzed, present in them potentially or in actuality (which of these is still disputable), and not itself divisible into bodies different in form. That is what all men mean by element. | |
From: Aristotle (On the Heavens [c.336 BCE], 302a05), quoted by Weisberg/Needham/Hendry - Philosophy of Chemistry 1.1 | |
A reaction: This is the classic definition of an element, which endured for a long time, and has been replaced by an 'actual components' view. Obviously analysis nowadays goes well beyond the atoms. |
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. |
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. |
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. |
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. |
399 | If the more you raise some earth the faster it moves, why does the whole earth not move? [Aristotle] |
Full Idea: If you raise some earth and release it, it moves and won't stay put, and the more you raise it the faster it moves, so why does the whole earth not move? | |
From: Aristotle (On the Heavens [c.336 BCE], 294a12) |
20918 | Void is a kind of place, so it can't explain place [Aristotle] |
Full Idea: It is absurd to explain place by the void, as though this latter were not itself some kind of place. | |
From: Aristotle (On the Heavens [c.336 BCE], 309b24) | |
A reaction: Presumably this is aimed at Democritus. |
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. |
403 | The earth must be round and of limited size, because moving north or south makes different stars visible [Aristotle] |
Full Idea: Clearly the earth is round and not of great size, because when we move north or south we find that very different stars are visible. | |
From: Aristotle (On the Heavens [c.336 BCE], 297b30) |
402 | The Earth must be spherical, because it casts a convex shadow on the moon [Aristotle] |
Full Idea: A lunar eclipse always has a convex dividing line, so, if it is eclipsed by the interposition of the earth, the circumference of the earth, being spherical, is responsible for the shape. | |
From: Aristotle (On the Heavens [c.336 BCE], 297b29) |
1498 | Everyone agrees that the world had a beginning, but thinkers disagree over whether it will end [Aristotle] |
Full Idea: All thinkers agree that the world had a beginning, but some claim that, having come into existence, it is everlasting. | |
From: Aristotle (On the Heavens [c.336 BCE], 279b12) |
395 | It seems possible that there exists a limited number of other worlds apart from this one [Aristotle] |
Full Idea: One might indeed be puzzled whether, just as the world about us exists, nothing prevents there being others as well, certainly more than one, though not an unlimited number | |
From: Aristotle (On the Heavens [c.336 BCE], 274a26) |