8 ideas
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! |
20618 | Persons must be conscious, reasoning, motivated, communicative, self-aware [Warren, by Tuckness/Wolf] |
Full Idea: Suggested characteristics of personhood: consciousness (esp. of pain); reasoning and problem solving; self-motivated activity; varied communication on many topics; self-concepts and self-awareness. | |
From: report of Mary Anne Warren (On the Moral and Legal State of Abortion [1973], p.55) by Tuckness,A/Wolf,C - This is Political Philosophy 8 'Standing' | |
A reaction: [a 'famous' article] A number of non-human animals come very close to passing these tests. I suspect the complex communication is only in there to disqualify them from getting the full certificate. (But she wrote on animal rights). |
7903 | The six perfections are giving, morality, patience, vigour, meditation, and wisdom [Nagarjuna] |
Full Idea: The six perfections are of giving, morality, patience, vigour, meditation, and wisdom. | |
From: Nagarjuna (Mahaprajnaparamitashastra [c.120], 88) | |
A reaction: What is 'morality', if giving is not part of it? I like patience and vigour being two of the virtues, which immediately implies an Aristotelian mean (which is always what is 'appropriate'). |