1+1=2: Is There a Proof or Acceptance?

  • Context: High School 
  • Thread starter Thread starter afton
  • Start date Start date
  • Tags Tags
    Acceptance Proof
Click For Summary

Discussion Overview

The discussion revolves around the question of whether there is a proof for the statement 1+1=2 or if it is simply accepted as a fundamental truth. Participants explore the mathematical logic, definitions, and philosophical implications surrounding this concept.

Discussion Character

  • Debate/contested
  • Conceptual clarification
  • Mathematical reasoning
  • Meta-discussion

Main Points Raised

  • Some participants question whether 1+1=2 can be proven or if it is merely accepted, referencing Peano's axioms as a foundational approach.
  • Others argue that the proof is trivial since 2 is often defined as 1+1, suggesting that the discussion is more about definitions than proof.
  • A few participants highlight the philosophical challenges in defining numbers, particularly "one" and "two," and how this complicates the proof of 1+1=2.
  • Some contributions mention Gödel's Incompleteness Theorem, suggesting that certain propositions in mathematics cannot be proven within their systems, which raises questions about the validity of proving 1+1=2.
  • There are discussions about using physical objects, like apples, to illustrate the concept of addition, with varying opinions on whether this effectively demonstrates the notion of addition.
  • One participant points out that if a different naming convention were used, such as calling the sum of one object and another "three," then 1+1 could equal 3, emphasizing the role of definitions in mathematics.
  • Several participants express that defining what "one" is remains a challenge, with some asserting that there is no difficulty in defining it as an isolated quantity.

Areas of Agreement / Disagreement

Participants do not reach a consensus; multiple competing views remain regarding the nature of proof, definitions, and the implications of Gödel's theorem on the discussion of 1+1=2.

Contextual Notes

The discussion reflects limitations in the definitions of numbers and the philosophical implications of mathematical truths, as well as the unresolved nature of certain mathematical propositions.

  • #31
Hurkyl said:
But the point still holds -- it can be done.

If you tell that person you taught to count to get 4 sticks of wood how would he actually know to get 4? They need a number to correspond to a quantity somewhere in the education. When I say teach someone to count I mean that they know the meaning of the numbers they are learning.
 
Physics news on Phys.org
  • #32
Well, not really. 4 is the successor of 3, which is the successor of 2 which is the succesor of 1. I think even dictionaries define 4 as one more than 3. Perhaps you could call that the meaning of "4". Who's got the definition of definition?

Blackadder: I have two beans, and I add two more beans, what do I have?
Baldrick: A very small casserole.
 
  • #33
When I say teach someone to count I mean that they know the meaning of the numbers they are learning.

Or, are you merely teaching them the art of labelling objects with an initial segment of positive integers?
 
  • #34
Hi,
I really don't think that it's worth arguing here.
We must accept that the natural numbers are: 0, 1, 2, 3, 4, 5, ...
And, if I had an honor to be the inventor of the natural number, I can make it whatever I like and my descendents just have to accept it. I can make it like:
1, 0, 5, 7, 10, 100, 20,... Or I can even create some more symbol to make different numbers.
Why 1 + 1 = 2 is you look at the array of natural number. Search where the 1 is and simply count from that number 1 more value, and you get 2.
And 2 + 3 = 5. Just do the same...
It's acceptable, and must be accepted, as you cannot do anything to change it.
It's basically correct... as I think.
Viet Dao,
 
  • #35
VietDao29 said:
Hi,
I really don't think that it's worth arguing here.
We must accept that the natural numbers are: 0, 1, 2, 3, 4, 5, ...
And, if I had an honor to be the inventor of the natural number, I can make it whatever I like and my descendents just have to accept it. I can make it like:
1, 0, 5, 7, 10, 100, 20,... Or I can even create some more symbol to make different numbers.
Why 1 + 1 = 2 is you look at the array of natural number. Search where the 1 is and simply count from that number 1 more value, and you get 2.
And 2 + 3 = 5. Just do the same...
It's acceptable, and must be accepted, as you cannot do anything to change it.
It's basically correct... as I think.
Viet Dao,

Are you arguing that "1" has no meaning, or that the meaning referenced by "1" cannot be defined? You seem to skip from "look I can change symbols!" to "you need '1' for '1'"

You always have to assume some rule before you can proceed in math. For example, "Math is logically consistent" is one of the main rules IMO ... Can you prove that math is logically consistent? well, it's one of the axioms, so if it isn't logically consistent it isn't math thus math is logically consistent.

Basically put: "1 + 1" can be represented the symbol we use to represent the quantity equal to "1 + 1", which is "2". Or am I being too 'superficial'?
 

Similar threads

  • · Replies 5 ·
Replies
5
Views
1K
  • · Replies 3 ·
Replies
3
Views
2K
  • · Replies 21 ·
Replies
21
Views
4K
  • · Replies 4 ·
Replies
4
Views
1K
Replies
15
Views
2K
  • · Replies 11 ·
Replies
11
Views
2K
  • · Replies 54 ·
2
Replies
54
Views
6K
  • · Replies 3 ·
Replies
3
Views
1K
  • · Replies 3 ·
Replies
3
Views
2K
  • · Replies 5 ·
Replies
5
Views
3K