## theabsurd 3 years ago Is there a proof for why: 1 + 1 = 2 I've heard of the Principua Mathematica, and that it came close but never fully did it.

1. JamesJ

On the contrary, they do prove it.

2. shinigami1m

whats the sense of 2 if its not 1+1

3. DHASHNI

2-1=1 and so 1+1=2

4. DHASHNI

LOL

5. theabsurd

I heard that they came close but never defined addition; after them godel came along and made things even more complicated.

6. JamesJ

You have to put that book in its historical context and the "project" that Russell and Whitehead were undertaking. Given their very careful definition of number, and definition of 1, and definition of 2, and definition of +, and definition of =, then do indeed show that 1 + 1 = 2. What they didn't do, and what Gödel's results cemented, is finish building up mathematics from elementary logical definitions.

7. theabsurd

Thank you, that cleared it up

8. JamesJ

9. JamesJ
10. JamesJ

If you want a relatively digestible accounting of the story, this isn't a bad resource.

11. theabsurd

thanks, it'll be useful. Until i'm one day ready to even attempt reading principua mathematica.

12. JamesJ

It's a bit of a historical curiosity now. If you're interested in Russell's definition of number, a much shorter and in many ways more useful book is this: http://www.amazon.com/Introduction-Mathematical-Philosophy-Bertrand-Russell/dp/0486277240/ref=sr_1_5?s=books&ie=UTF8&qid=1324525990&sr=1-5