41 ideas
12274 | Begin examination with basics, and subdivide till you can go no further [Aristotle] |
Full Idea: The examination must be carried on and begin from the primary classes and then go on step by step until further division is impossible. | |
From: Aristotle (Topics [c.331 BCE], 109b17) | |
A reaction: This is a good slogan for the analytic approach to thought. I take Aristotle (or possibly Socrates) to be the father of analysis, not Frege (though see Idea 9840). (He may be thinking of the tableau method of proof). |
12260 | Dialectic starts from generally accepted opinions [Aristotle] |
Full Idea: Reasoning is dialectical which reasons from generally accepted opinions. | |
From: Aristotle (Topics [c.331 BCE], 100a30) | |
A reaction: This is right at the heart of Aristotle's philosophical method, and Greek thinking generally. There are nice modern debates about 'folk' understanding, derived from science (e.g. quantum theory) which suggest that starting from normal views is a bad idea. |
12291 | There can't be one definition of two things, or two definitions of the same thing [Aristotle] |
Full Idea: There cannot possibly be one definition of two things, or two definitions of the same thing. | |
From: Aristotle (Topics [c.331 BCE], 154a11) | |
A reaction: The second half of this is much bolder and more controversial, and plenty of modern thinkers would flatly reject it. Are definitions contextual, that is, designed for some specific human purpose. Must definitions be of causes? |
12292 | Definitions are easily destroyed, since they can contain very many assertions [Aristotle] |
Full Idea: A definition is the easiest of all things to destroy; for, since it contains many assertions, the opportunities which it offers are very numerous, and the more abundant the material, the more quickly the reasoning can set to work. | |
From: Aristotle (Topics [c.331 BCE], 155a03) | |
A reaction: I quote this to show that Aristotle expected many definitions to be very long affairs (maybe even of book length?) |
12283 | In definitions the first term to be assigned ought to be the genus [Aristotle] |
Full Idea: In definitions the first term to be assigned ought to be the genus. | |
From: Aristotle (Topics [c.331 BCE], 132a12) | |
A reaction: We mustn't be deluded into thinking that nothing else is required. I take the increasing refinement of differentiae to be where the real action is. The genus gives you 70% of the explanation. |
12272 | We describe the essence of a particular thing by means of its differentiae [Aristotle] |
Full Idea: We usually isolate the appropriate description of the essence of a particular thing by means of the differentiae which are peculiar to it. | |
From: Aristotle (Topics [c.331 BCE], 108b05) | |
A reaction: I take this to be important for showing the definition is more than mere categorisation. A good definition homes in the particular, by gradually narrowing down the differentiae. |
12279 | The differentia indicate the qualities, but not the essence [Aristotle] |
Full Idea: No differentia indicates the essence [ti estin], but rather some quality, such as 'pedestrian' or 'biped'. | |
From: Aristotle (Topics [c.331 BCE], 122b17) | |
A reaction: We must disentangle this, since essence is what is definable, and definition seems to give us the essence, and yet it appears that definition only requires genus and differentia. Differentiae seem to be both generic and fine-grained. See Idea 12280! |
12261 | Differentia are generic, and belong with genus [Aristotle] |
Full Idea: The differentia, being generic in character, should be ranged with the genus. | |
From: Aristotle (Topics [c.331 BCE], 101b18) | |
A reaction: This does not mean that naming the differentia amounts to mere classification. I presume we can only state individual differences by using a language which is crammed full of universals. |
12263 | 'Genus' is part of the essence shared among several things [Aristotle] |
Full Idea: A 'genus' is that which is predicated in the category of essence of several things which differ in kind. | |
From: Aristotle (Topics [c.331 BCE], 102a32) | |
A reaction: Hence a genus is likely to be expressed by a universal, a one-over-many. A particular will be a highly individual collection of various genera, but what ensures the uniqueness of each thing, if they are indiscernible? |
12289 | The genera and the differentiae are part of the essence [Aristotle] |
Full Idea: The genera and the differentiae are predicated in the category of essence. | |
From: Aristotle (Topics [c.331 BCE], 153a19) | |
A reaction: The definition is words, and the essence is real, so our best definition might not fully attain to the essence. Aristotle has us reaching out to the world through our definitions. |
12285 | The definition is peculiar to one thing, not common to many [Aristotle] |
Full Idea: The definition ought to be peculiar to one thing, not common to many. | |
From: Aristotle (Topics [c.331 BCE], 149b24) | |
A reaction: I take this to be very important, against those who think that definition is no more than mere categorisation. To explain, you must get down to the level of the individual. We must explain that uniquely docile tiger. |
16489 | Is it possible to state every possible truth about the whole course of nature without using 'not'? [Russell] |
Full Idea: Imagine a person who knew everything that can be stated without using the word 'not' or some equivalent; would such a person know the whole course of nature, or would he not? | |
From: Bertrand Russell (Human Knowledge: its scope and limits [1948], 9) | |
A reaction: Nowadays we might express Russell's thought as 'Does God need the word 'not'?'. Russell's thesis is that such words concern psychology, and not physics. God would need 'not' to describe how human minds work. |
11261 | Puzzles arise when reasoning seems equal on both sides [Aristotle] |
Full Idea: The equality of opposite reasonings is the cause of aporia; for it is when we reason on both [sides of a question] and it appears to us that everything can come about either way, that we are in a state of aporia about which of the two ways to take up. | |
From: Aristotle (Topics [c.331 BCE], 145b17), quoted by Vassilis Politis - Aristotle and the Metaphysics 3.1 | |
A reaction: Other philosophers give up on the subject in this situation, but I love Aristotle because he takes this to be the place where philosophy begins. |
12273 | Unit is the starting point of number [Aristotle] |
Full Idea: They say that the unit [monada] is the starting point of number (and the point the starting-point of a line). | |
From: Aristotle (Topics [c.331 BCE], 108b30) | |
A reaction: Yes, despite Frege's objections in the early part of the 'Grundlagen' (1884). I take arithmetic to be rooted in counting, despite all abstract definitions of number by Frege and Dedekind. Identity gives the unit, which is countable. See also Topics 141b9 |
12267 | There are ten categories: essence, quantity, quality, relation, place, time, position, state, activity, passivity [Aristotle] |
Full Idea: The four main types of predicates fall into ten categories: essence, quantity, quality, relation, place, time, position, state, activity, passivity. | |
From: Aristotle (Topics [c.331 BCE], 103b20) | |
A reaction: These are the standard ten categories of Aristotle. He is notable for the divisions not being sharp, and ten being a rough total. He is well aware of the limits of precision in such matters. |
12282 | An individual property has to exist (in past, present or future) [Aristotle] |
Full Idea: If it does not at present exist, or, if it has not existed in the past, or if it is not going to exist in the future, it will not be a property [idion] at all. | |
From: Aristotle (Topics [c.331 BCE], 129a27) | |
A reaction: This seems to cramp our style in counterfactual discussion. Can't we even mention an individual property if we believe that it will never exist. Utopian political discussion will have to cease! |
12264 | An 'accident' is something which may possibly either belong or not belong to a thing [Aristotle] |
Full Idea: An 'accident' [sumbebekos] is something which may possibly either belong or not belong to any one and the self-same thing, such as 'sitting posture' or 'whiteness'. This is the best definition, because it tells us the essential meaning of the term itself. | |
From: Aristotle (Topics [c.331 BCE], 102b07) | |
A reaction: Thus a car could be red, or not red. Accidents are contingent. It does not follow that necessary properties are essential (see Idea 12262). There are accidents [sumbebekos], propria [idion] and essences [to ti en einai]. |
12280 | Genus gives the essence better than the differentiae do [Aristotle] |
Full Idea: In assigning the essence [ti estin], it is more appropriate to state the genus than the differentiae; for he who describes 'man' as an 'animal' indicates his essence better than he who describes him as 'pedestrian'. | |
From: Aristotle (Topics [c.331 BCE], 128a24) | |
A reaction: See Idea 12279. This idea is only part of the story. My reading of this is simply that assigning a genus gives more information. We learn more about him when we say he is a man than when we say he is Socrates. |
13269 | In the case of a house the parts can exist without the whole, so parts are not the whole [Aristotle] |
Full Idea: In the case of a house, where the process of compounding the parts is obvious, though the parts exist, there is no reason why the whole should not be non-existent, and so the parts are not the same as the whole. | |
From: Aristotle (Topics [c.331 BCE], 150a19) | |
A reaction: Compare buying a piece of furniture, and being surprised to discover, when it is delivered, that it is self-assembly. This idea is a simple refutation of the claims of classical mereology, that wholes are just some parts. Aristotle uses modal claims. |
12284 | Everything that is has one single essence [Aristotle] |
Full Idea: Everything that is has one single essence [en esti to einai]. | |
From: Aristotle (Topics [c.331 BCE], 141a36) | |
A reaction: Does this include vague objects, and abstract 'objects'? Sceptics might ask what grounds this claim. Does Dr Jeckyll have two essences? |
12262 | An 'idion' belongs uniquely to a thing, but is not part of its essence [Aristotle] |
Full Idea: A property [idion] is something which does not show the essence of a thing but belongs to it alone. ...No one calls anything a property which can possibly belong to something else. | |
From: Aristotle (Topics [c.331 BCE], 102a18) | |
A reaction: [See Charlotte Witt 106 on this] 'Property' is clearly a bad translation for such an individual item. Witt uses 'proprium', which is a necessary but nonessential property of something. Necessity is NOT the hallmark of essence. See Idea 12266. |
12290 | Destruction is dissolution of essence [Aristotle] |
Full Idea: Destruction is a dissolution of essence. | |
From: Aristotle (Topics [c.331 BCE], 153b30) | |
A reaction: [plucked from context!] I can't think of a better way to define destruction, in order to distinguish it from damage. A vase is destroyed when its essential function cannot be recovered. |
12286 | If two things are the same, they must have the same source and origin [Aristotle] |
Full Idea: When things are absolutely the same, their coming-into-being and destruction are also the same and so are the agents of their production and destruction. | |
From: Aristotle (Topics [c.331 BCE], 152a02) | |
A reaction: Thus Queen Elizabeth II has to be the result of that particular birth, and from those particular parents, as Kripke says? The inverse may not be true. Do twins have a single origin? Things that fission and then re-fuse differently? etc |
12288 | Numerical sameness and generic sameness are not the same [Aristotle] |
Full Idea: Things which are the same specifically or generically are not necessarily the same or cannot possibly be the same numerically. | |
From: Aristotle (Topics [c.331 BCE], 152b32) | |
A reaction: See also Idea 12266. This looks to me to be a pretty precise anticipation of Peirce's type/token distinction, but without the terminology. It is reassuring that Aristotle spotted it, as that makes it more likely to be a genuine distinction. |
12266 | 'Same' is mainly for names or definitions, but also for propria, and for accidents [Aristotle] |
Full Idea: 'The same' is employed in several senses: its principal sense is for same name or same definition; a second sense occurs when sameness is applied to a property [idiu]; a third sense is applied to an accident. | |
From: Aristotle (Topics [c.331 BCE], 103a24-33) | |
A reaction: [compressed] 'Property' is better translated as 'proprium' - a property unique to a particular thing, but not essential - see Idea 12262. Things are made up of essence, propria and accidents, and three ways of being 'the same' are the result. |
12287 | Two identical things have the same accidents, they are the same; if the accidents differ, they're different [Aristotle] |
Full Idea: If two things are the same then any accident of one must also be an accident of the other, and, if one of them is an accident of something else, so must the other be also. For, if there is any discrepancy on these points, obviously they are not the same. | |
From: Aristotle (Topics [c.331 BCE], 152a36) | |
A reaction: So what is always called 'Leibniz's Law' should actually be 'Aristotle's Law'! I can't see anything missing from the Aristotle version, but then, since most people think it is pretty obvious, you would expect the great stater of the obvious to get it. |
16490 | Some facts about experience feel like logical necessities [Russell] |
Full Idea: The impossibility of seeing two colours simultaneously in a given direction feels like a logical impossibility. | |
From: Bertrand Russell (Human Knowledge: its scope and limits [1948], 9) | |
A reaction: I presume all necessities feel equally necessary. If we distinguish necessities by what gives rise to them (a view I favour) then how strong they 'feel' will be irrelevant. We can see why Russell is puzzled by the phenomenon, though. |
12259 | Reasoning is when some results follow necessarily from certain claims [Aristotle] |
Full Idea: Reasoning [sullogismos] is a discussion in which, certain things having been laid down, something other than these things necessarily results through them. | |
From: Aristotle (Topics [c.331 BCE], 100a25) | |
A reaction: This is cited as the standard statement of the nature of logical necessity. One might challenge either the very word 'necessary', or the exact sense of the word employed here. Is it, in fact, metaphysical, or merely analytic? |
16488 | It is hard to explain how a sentence like 'it is not raining' can be found true by observation [Russell] |
Full Idea: If 'it is not raining' means 'the sentence "it is raining" is false', that makes it almost impossible to understand how a sentence containing the word 'not' can be found true by observation. | |
From: Bertrand Russell (Human Knowledge: its scope and limits [1948], 9) | |
A reaction: Russell goes on to explore the general difficulty of deciding negative truths by observation. The same problem arises for truthmaker theory. Obviously I can observe that it isn't raining, but it seems parasitic on observing when it is raining. |
12271 | Induction is the progress from particulars to universals [Aristotle] |
Full Idea: Induction is the progress from particulars to universals; if the skilled pilot is the best pilot and the skilled charioteer the best charioteer, then, in general, the skilled man is the best man in any particular sphere. | |
From: Aristotle (Topics [c.331 BCE], 105a15) | |
A reaction: It is a bit unclear whether we are deriving universal concepts, or merely general truths. Need general truths be absolute or necessary truths? Presumably occasionally the best person is not the most skilled, as in playing a musical instrument. |
12293 | We say 'so in cases of this kind', but how do you decide what is 'of this kind'? [Aristotle] |
Full Idea: When it is necessary to establish the universal, people use the expression 'So in all cases of this kind'; but it is one of the most difficult tasks to define which of the terms proposed are 'of this kind' and which are not. | |
From: Aristotle (Topics [c.331 BCE], 157a25) | |
A reaction: It is particularly hard if induction is expressed as the search for universals, since the kind presumably is the universal, so the universal must be known before the induction can apply, which really is the most frightful nuisance for truth-seekers. |
16491 | If we define 'this is not blue' as disbelief in 'this is blue', we eliminate 'not' as an ingredient of facts [Russell] |
Full Idea: We can reintroduce 'not' by a definition: the words 'this is not blue' are defined as expressing disbelief in what is expressed by the words 'this is blue'. In this way the need of 'not' as an indefinable constituent of facts is avoided. | |
From: Bertrand Russell (Human Knowledge: its scope and limits [1948], 9) | |
A reaction: This is part of Russell's programme of giving a psychological account of logical connectives. See other ideas from his 1940 and 1948 works. He observes that disbelief is a state just as positive as belief. I love it. |
12277 | Friendship is preferable to money, since its excess is preferable [Aristotle] |
Full Idea: Friendship is preferable to money; for excess of friendship is preferable to excess of money. | |
From: Aristotle (Topics [c.331 BCE], 118b07) | |
A reaction: Compare Idea 12276, which gives a different criterion for choosing between virtues. This idea is an interesting qualification of the doctrine of the mean. |
12276 | Justice and self-control are better than courage, because they are always useful [Aristotle] |
Full Idea: Justice [dikaiosune] and self-control [sophrosune] are preferable to courage, for the first two are always useful, but courage only sometimes. | |
From: Aristotle (Topics [c.331 BCE], 117a36) | |
A reaction: One could challenge his criterion. What of something which is absolutely vital on occasions, against something which is very mildly useful all the time? You may survive without justice, but not without courage. Compare Idea 12277. |
12275 | We value friendship just for its own sake [Aristotle] |
Full Idea: We value friendship for its own sake, even if we are not likely to get anything else from it. | |
From: Aristotle (Topics [c.331 BCE], 117a03) | |
A reaction: In 'Ethics' he distinguishes some friendships which don't meet this requirement. Presumably true friendships survive all vicissitudes (except betrayal), but that makes such things fairly rare. |
12281 | Man is intrinsically a civilized animal [Aristotle] |
Full Idea: It is an essential [kath' auto] property of man to be 'by nature a civilized animal'. | |
From: Aristotle (Topics [c.331 BCE], 128b17) | |
A reaction: I take this, along with man being intrinsically rational, to be the foundation of Aristotelian ethics. Given that we are civilized, self-evident criteria emerge for how to be good at it. A good person is, above all, a good citizen. |
1748 | Archelaus was the first person to say that the universe is boundless [Archelaus, by Diog. Laertius] |
Full Idea: Archelaus was the first person to say that the universe is boundless. | |
From: report of Archelaus (fragments/reports [c.450 BCE]) by Diogenes Laertius - Lives of Eminent Philosophers 02.Ar.3 |
12265 | All water is the same, because of a certain similarity [Aristotle] |
Full Idea: Any water is said to be specifically the same as any other water because it has a certain similarity to it. | |
From: Aristotle (Topics [c.331 BCE], 103a20) | |
A reaction: (Cf. Idea 8153) It take this to be the hallmark of a natural kind, and we should not lose sight of it in the midst of discussions about rigid designation and essential identity. Tigers are only a natural kind insofar as they are indistinguishable. |
4786 | Russell's 'at-at' theory says motion is to be at the intervening points at the intervening instants [Russell, by Psillos] |
Full Idea: To reply to Zeno's Arrow Paradox, Russell developed his 'at-at' theory of motion, which says that to move from A to B is to be at the intervening points at the intervening instants. | |
From: report of Bertrand Russell (Human Knowledge: its scope and limits [1948]) by Stathis Psillos - Causation and Explanation §4.2 | |
A reaction: I wonder whether Russell's target was actually Zeno, or was it a simplified ontology of points and instants? The ontology will also need identity, to ensure it is the same thing which arrives at each point. |
5989 | Archelaus said life began in a primeval slime [Archelaus, by Schofield] |
Full Idea: Archelaus wrote that life on Earth began in a primeval slime. | |
From: report of Archelaus (fragments/reports [c.450 BCE]) by Malcolm Schofield - Archelaus | |
A reaction: This sounds like a fairly clearcut assertion of the production of life by evolution. Darwin's contribution was to propose the mechanism for achieving it. We should honour the name of Archelaus for this idea. |
12278 | 'Being' and 'oneness' are predicated of everything which exists [Aristotle] |
Full Idea: 'Being' and 'oneness' are predicated of everything which exists. | |
From: Aristotle (Topics [c.331 BCE], 121a18) | |
A reaction: Is 'oneness' predicated of water? So existence always was a predicate, it seems, until Kant told us it wasn't. That existence is a quantifier, not a predicate, seems to be up for question again these days. |