# [extropy-chat] Maths ability

Eliezer S. Yudkowsky sentience at pobox.com
Sun Mar 5 18:35:11 UTC 2006

```ben wrote:
>
> Excel says (-1) - (-1) = 0. But i still don't really understand why.
> "two minuses make a plus" isn't an explanation.

Argh, I can't resist:

3 - 3 = 0
4 - 4 = 0
0 - 0 = 0
20 - 20 = 0
generalize
x - x = 0
let x equal -1
(-1) - (-1) = 0

Everything, minus itself, equals zero - when it meets its antiparticle
it annihilates and nothing is left.  This applies to both negative
numbers and positive numbers.  If you have one apple, and you take away
one apple, you have no apples.  If you have one anti-apple, and you take
away one anti-apple, you have no anti-apples.

> --- Lee Corbin <lcorbin at tsoft.com> wrote:
>
>>>Damn right.  Me, every since I was a little kid, I had a "math
>>>line" that quickly, visually, and easily came to me that told me
>>>the answer to many problems.  See "The Math Gene" by Keith Devlin.
>
> What?!
> I'm not sure if i understand what you mean. Are you saying that you (and
> at you in the way that, say, spelling mistakes in a sentence can?

Yes, that's a good analogy.  I'll look at something and instantly go,
"That can't possibly be right" and then it takes me another minute to
figure out where it's wrong.

> If so, i find that idea deeply wierd.

A dyslexic may feel the same way about your ability to spot spelling
mistakes in a sentence.

> Anyway, this is getting a little bit off track. My point was not to ask
> for help with maths (!) but to point out that 'try harder' is not really
> much use to someone who has difficulty with it. It's like telling a
> depressed person to just pull themselves together.
>
> Actually, it's quite possible that having people that are inherently
> innumerate could be a good thing. Diversity and all that.

Watch out!  This is the kind of thinking that leads people to decide
that aging is good for you and smallpox is God's will.  Math disability
= BAD.  Like death itself, math disability is pure downside without the
slightest redeeming feature; not even the learning-value of resting your
hand on a hot stove.  That cloud has no silver lining.  None whatsoever.
Never forget, never forgive, never accept, never apologize; just solve
the goddamn problem.  Keep the bad thing squarely in your crosshairs and
go on working toward the day when you can finally squeeze the trigger.

--
Eliezer S. Yudkowsky                          http://singinst.org/
Research Fellow, Singularity Institute for Artificial Intelligence

```