off topic but please forgive me me and answer

Steven D'Aprano steve at REMOVE-THIS-cybersource.com.au
Sat Apr 3 17:17:05 CEST 2010


On Sat, 03 Apr 2010 15:43:41 +0100, Martin P. Hellwig wrote:

> I am replying to this post not because I disagree but because it
> postalogically  fits the best (I am by no means an expert either).
> 
> IMHO, the crackpot in this regard is actually partially right,
> multiplication does mean that the number must get bigger, however for
> fractions you multiply four numbers, two numerators and two
> denominators. The resulting numerator and denominator by this
> multiplication get indeed bigger.

But you're not multiplying four numbers, you're multiplying two numbers. 
One-half is not "two numbers", that would be a tuple or a list or 
possibly a coordinate pair. One-half is a single number, the number which 
if you double it gives one.

Fortunately multiplication is consistent. Multiplying the two numbers 0.5 
and 0.5 is exactly the same as multiplying 1*1 and 2*2 then dividing to 
get a single number. It's not the same as multiplying 1*1 and 2*2 to get 
two numbers, 1 and 4.

You say that multiplication means that the number "must get bigger". 

5*1 = 5
5*0 = 0
5*-2 = -10

I hope you won't try to argue that 5, 0 and -10 are all bigger than 5.

There really is no point trying to dignify superpollo's friend's 
assertion on the basis of some technicality. His argument is no different 
from the argument that says that pythons are snakes, and therefore python 
can't be a programming language and this newsgroup can't possibly exist. 
Words can have multiple meanings, and meanings can shift. Multiply may be 
derived from a word which, once upon a time, meant to get bigger, but 
that's not what multiply means. I don't like to dismiss somebody I've 
never met, but on the basis of what superpollo says, yes, he's a crackpot.

Either that or about age four. When I was four I strongly believed that 
"one hundred" and "a hundred" were different numbers. I argued (not very 
convincingly, but with great vehemence) to my teacher and my parents that 
you counted up to ninety-nine, then a hundred, a hundred and one, a 
hundred and two, ... a hundred and ninety-nine, *one* hundred.


-- 
Steven



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