13 ideas
| 12268 | Contradiction is impossible [Antisthenes (I), by Aristotle] |
| Full Idea: Antisthenes said that contradiction is impossible. | |
| From: report of Antisthenes (Ath) (fragments/reports [c.405 BCE]) by Aristotle - Topics 104b21 | |
| A reaction: Aristotle is giving an example of a 'thesis'. It should be taken seriously if a philosopher proposes it, but dismissed as rubbish if anyone else proposes it! No context is given for the remark. |
| 602 | Some fools think you cannot define anything, but only say what it is like [Antisthenes (I), by Aristotle] |
| Full Idea: There is an application of that old chestnut of the cynic Antisthenes' followers (and other buffoons of that kind). Their claim was that a definition of what something is is impossible. You cannot define silver, though you can say it is like tin. | |
| From: report of Antisthenes (Ath) (fragments/reports [c.405 BCE]) by Aristotle - Metaphysics 1043b |
| 15717 | Using Choice, you can cut up a small ball and make an enormous one from the pieces [Kaplan/Kaplan] |
| Full Idea: The problem with the Axiom of Choice is that it allows an initiate (by an ingenious train of reasoning) to cut a golf ball into a finite number of pieces and put them together again to make a globe as big as the sun. | |
| From: R Kaplan / E Kaplan (The Art of the Infinite [2003], 9) | |
| A reaction: I'm not sure how this works (and I think it was proposed by the young Tarski), but it sounds like a real problem to me, for all the modern assumptions that Choice is fine. |
| 15712 | 1 and 0, then add for naturals, subtract for negatives, divide for rationals, take roots for irrationals [Kaplan/Kaplan] |
| Full Idea: You have 1 and 0, something and nothing. Adding gives us the naturals. Subtracting brings the negatives into light; dividing, the rationals; only with a new operation, taking of roots, do the irrationals show themselves. | |
| From: R Kaplan / E Kaplan (The Art of the Infinite [2003], 1 'Mind') | |
| A reaction: The suggestion is constructivist, I suppose - that it is only operations that produce numbers. They go on to show that complex numbers don't quite fit the pattern. |
| 15711 | The rationals are everywhere - the irrationals are everywhere else [Kaplan/Kaplan] |
| Full Idea: The rationals are everywhere - the irrationals are everywhere else. | |
| From: R Kaplan / E Kaplan (The Art of the Infinite [2003], 1 'Nameless') | |
| A reaction: Nice. That is, the rationals may be dense (you can always find another one in any gap), but the irrationals are continuous (no gaps). |
| 15714 | 'Commutative' laws say order makes no difference; 'associative' laws say groupings make no difference [Kaplan/Kaplan] |
| Full Idea: The 'commutative' laws say the order in which you add or multiply two numbers makes no difference; ...the 'associative' laws declare that regrouping couldn't change a sum or product (e.g. a+(b+c)=(a+b)+c ). | |
| From: R Kaplan / E Kaplan (The Art of the Infinite [2003], 2 'Tablets') | |
| A reaction: This seem utterly self-evident, but in more complex systems they can break down, so it is worth being conscious of them. |
| 15715 | 'Distributive' laws say if you add then multiply, or multiply then add, you get the same result [Kaplan/Kaplan] |
| Full Idea: The 'distributive' law says you will get the same result if you first add two numbers, and then multiply them by a third, or first multiply each by the third and then add the results (i.e. a · (b+c) = a · b + a · c ). | |
| From: R Kaplan / E Kaplan (The Art of the Infinite [2003], 2 'Tablets') | |
| A reaction: Obviously this will depend on getting the brackets right, to ensure you are indeed doing the same operations both ways. |
| 15713 | The first million numbers confirm that no number is greater than a million [Kaplan/Kaplan] |
| Full Idea: The claim that no number is greater than a million is confirmed by the first million test cases. | |
| From: R Kaplan / E Kaplan (The Art of the Infinite [2003], 2 'Intro') | |
| A reaction: Extrapolate from this, and you can have as large a number of cases as you could possibly think of failing to do the inductive job. Love it! Induction isn't about accumulations of cases. It is about explanation, which is about essence. Yes! |
| 1664 | I would rather go mad than experience pleasure [Antisthenes (I)] |
| Full Idea: I would rather go mad than experience pleasure. | |
| From: Antisthenes (Ath) (fragments/reports [c.405 BCE]), quoted by Diogenes Laertius - Lives of Eminent Philosophers 06.3 | |
| A reaction: Did he actually prefer pain? If both experiences would drive him mad, it seems like a desire for death. I cannot understand why anyone is opposed to harmless pleasures. |
| 21385 | Antisthenes said virtue is teachable and permanent, is life's goal, and is like universal wealth [Antisthenes (I), by Long] |
| Full Idea: The moral propositions of Antisthenes foreshadowed the Stoics: virtue can be taught and once acquired cannot be lost (fr.69,71); virtue is the goal of life (22); the sage is self-sufficient, since he has (by being wise) the wealth of all men (8o). | |
| From: report of Antisthenes (Ath) (fragments/reports [c.405 BCE]) by A.A. Long - Hellenistic Philosophy 1 | |
| A reaction: [He cites Caizzi for the fragments] The distinctive idea here is (I think) that once acquired virtue can never be lost. It sounds plausible, but I'm wondering why it should be true. Is it like riding a bicycle, or like learning to speak Russian? |
| 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 |
| 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. |
| 2631 | Antisthenes says there is only one god, which is nature [Antisthenes (I), by Cicero] |
| Full Idea: Antisthenes says there is only one god, which is nature. | |
| From: report of Antisthenes (Ath) (fragments/reports [c.405 BCE]) by M. Tullius Cicero - On the Nature of the Gods ('De natura deorum') I.32 |