Proof that 1+1=2 (2 Viewers)

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Captain pi

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Of course we can't prove that 1 + 1 = 2 without reverting to the definition of 2 as

2 (is equivalent to) = 1' = 1 + 1.

Just the same as we can't prove, (upside-down A) a:

1 × a = a

or

0 + a = a

However, to dispute them is foolish; they are true ipso facto. (I think some users much more knowledgeable on Gödel will strangely loop back on me after that remark.)

How do you think we conceptualize "2", anyway? "2" and "Two" are just cognitive metaphors for 1 + 1.
 

Slidey

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Captain pi said:
However, to dispute them is foolish; they are true ipso facto. (I think some users much more knowledgeable on Gödel will strangely loop back on me after that remark.)
The trouble here is those two things you mentioned are axioms. There is a finite number of them and for all intents and purposes, there is no problem with them.

However, when it comes to defining the natural numbers, we must use a recursive axiom set - one with an infinite amount of axioms. That is a problem.

Archman, if you don't like logic, avoid threads on it and don't take discrete, et cetera at uni. Simple. Stop complaining.
 

Templar

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Slide Rule said:
However, when it comes to defining the natural numbers, we must use a recursive axiom set - one with an infinite amount of axioms. That is a problem.
I thought that even with infinite amount of axioms you couldn't prove their consistency.
 

Slidey

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Templar said:
I thought that even with infinite amount of axioms you couldn't prove their consistency.
Perhaps. I don't profess prowess on Goedelian logic.
 

Archman

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Slide Rule said:
The trouble here is those two things you mentioned are axioms. There is a finite number of them and for all intents and purposes, there is no problem with them.

However, when it comes to defining the natural numbers, we must use a recursive axiom set - one with an infinite amount of axioms. That is a problem.

Archman, if you don't like logic, avoid threads on it and don't take discrete, et cetera at uni. Simple. Stop complaining.
no, logic is not my problem. the problem being the fact that the actual issue was addressed perfectly well in the first few posts. yet others like to sustain an ongoing trend of stating the obvious and the irrelevant. (like people should read all previous posts before asking the same question). bah don't mean to spoil any fun for anyone, but i don't think a "proof" osuch as: take 1=1 and add one to both sides is contributing in anyway to the discussion.
also why don't you give some web references to the axioms or something, im sure there are some out there, surely thats better than some of the explanations we've had so far.

oh yes, im the last person to be taking discrete above calculus on my priority list. (will probably end up doing them all anyway)
 

Slidey

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Archman said:
no, logic is not my problem. the problem being the fact that the actual issue was addressed perfectly well in the first few posts. yet others like to sustain an ongoing trend of stating the obvious and the irrelevant. (like people should read all previous posts before asking the same question). bah don't mean to spoil any fun for anyone, but i don't think a "proof" osuch as: take 1=1 and add one to both sides is contributing in anyway to the discussion.
also why don't you give some web references to the axioms or something, im sure there are some out there, surely thats better than some of the explanations we've had so far.

oh yes, im the last person to be taking discrete above calculus on my priority list. (will probably end up doing them all anyway)
Understood and I apologise.

I agree there's nothing inherently entertaining or interesting in proving 1+1=2, however how it is proved is what interests me.

This one is probably the best: http://en.wikipedia.org/wiki/G%F6del's_incompleteness_theorem
 

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Slide Rule said:
I agree there's nothing inherently entertaining or interesting in proving 1+1=2, however how it is proved is what interests me.
Aren't you stating the obvious though, seriously who doesn't know 1+1=2 before they came to this thread? I've learnt that truth before I could even speak properly. I know you didn't say: "I don't know 1+1=2", but when people prove something in math it's either to assert the result or to find the 'how' element. Agree? So thats why I think you are stating the obvious, because of course we want to know how, it's not like people are not sure about if 1+1=2.

I think Archman's problem is not liking the fact that everyone don't read whats already been said and keeps on restating the obvious and hence prolonging the thread. And people tend to make up their own argument without any formal mathematical basis.
 
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m_isk

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actually, 1=2. Bear with me
let x=1 and Y=1
then x=y
and x^2=xy (multiplying both sides by x)
and x^2-y^2=xy-y^2 (subtracting y squared from both sides)
therefore, upon factorising, (x-y)(x+y) = y(x-y)
and when we cross of the (x-y) from both sides, we get x+y=y, but since x=1 and y=1, we have proved that 1+1=1 i.e that 1=2!
:) so all the maths we do and will ever do and have ever done is garbage. go figure geniuses or is it geniusi??
 
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KFunk

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Haha, next time I'm stuck in a test I'll just prove that the rules we work with are fundamentally flawed.
 

Xayma

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m_isk said:
actually, 1=2. Bear with me
let x=1 and Y=1
then x=y
and x^2=xy (multiplying both sides by x)
and x^2-y^2=xy-y^2 (subtracting y squared from both sides)
therefore, upon factorising, (x-y)(x+y) = y(x-y)
and when we cross of the (x-y) from both sides, we get x+y=y, but since x=1 and y=1, we have proved that 1+1=1 i.e that 1=2!
:) so all the maths we do and will ever do and have ever done is garbage. go figure geniuses or is it geniusi??
True that happens when you start using undefined numbers. In this case something divided by 0.
 

Templar

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There was absolute no point in that post. This thread is pretty much closed.
 

dark_angel

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Templar said:
There was absolute no point in that post. This thread is pretty much closed.
do u know how many maths terms u just used in that sentence?????


neither do i :)






absolute, point, thread, closed.

i'm really bored.
 
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xeuyrawp

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Euler said:
Bertrand Russell, though i don't remember which volume it is in.
Jesus, Russell is like one of the biggest muscles in Philosophy... AND math?
 

Slidey

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PwarYuex said:
Jesus, Russell is like one of the biggest muscles in Philosophy... AND math?
Most philosophers were mathematicians...
 
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