The Math Forum

Search All of the Math Forum:

Views expressed in these public forums are not endorsed by NCTM or The Math Forum.

Math Forum » Discussions » sci.math.* » sci.math

Notice: We are no longer accepting new posts, but the forums will continue to be readable.

Topic: Is it possible that 3+4=8?
Replies: 21   Last Post: Jan 29, 2011 9:06 AM

Advanced Search

Back to Topic List Back to Topic List Jump to Tree View Jump to Tree View   Messages: [ Previous | Next ]

Posts: 4,165
From: London
Registered: 2/8/08
Re: Is it possible that 3+4=8?
Posted: Jan 23, 2011 3:31 PM
  Click to see the message monospaced in plain text Plain Text   Click to reply to this topic Reply

On Jan 23, 7:47 pm, Craig Feinstein <> wrote:
> Let's pretend that we live in a world where there are invisible pixies
> running around messing everything up. Let's say you have 3 balls in
> your left hand and 4 balls in your right hand. Whenever you combine
> the balls together, one of these invisible pixies secretly throws in
> another ball, so that whenever you count the balls, you come up with 8
> balls. So in this pretend world, it is a known fact that 3+4=8. Anyone
> who disputes this fact in our pretend world is considered either crazy
> or stupid.
> In our real world, it is a known fact that 3+4=7. But how can we be
> sure that there are no invisible pixies running around taking balls
> away from us causing us to think that 3+4=7 when really 3+4=8?
> My point is that mathematics is considered a deductive science, in
> which everything is absolutely certain. But how can mathematics prove
> that the above scenario cannot be true?

I don't think mathematics is a deductive science: mathematics is
hardly a science at all. OTOH, in a world were 3+4=7, I'd also expect
1=/=0: i.e. no mathematical fact exists in isolation...


Point your RSS reader here for a feed of the latest messages in this topic.

[Privacy Policy] [Terms of Use]

© The Math Forum at NCTM 1994-2018. All Rights Reserved.