• thedeadidea
    98
    1 + 1 = 2 is True.

    It is True in the sense of an indisputable fact of a mathematical operation... It as its own statement is its own means and ends.

    Let those who wish to quibble over the foundation of maths, epistemic truth and semantic version of truth without substantiating any terms do so at their leisure.
  • TheMadFool
    13.8k


    Suppose 1 + 1 =/= 2
    1 + 1 - 1 =/= 2 - 1
    1 =/= 1

    Contradiction

    Therefore 1 + 1 = 2
  • Pattern-chaser
    1.8k
    “1”, “+”, “=“, and “2” have specific meanings by convention. So, “1+1=2” is a tautology. It has to be true given the meanings of the terms used. There is nothing to prove.Noah Te Stroete

    Yes, once we have accepted the axioms and theorems of set theory, number theory and arithmetic, we find that "1 + 1 = 2" is defined to be true. It cannot but be true.
  • Pattern-chaser
    1.8k
    ↪Noah Te Stroete Wtf are you doing on this forum?Nicholas Ferreira

    Philosophy?
  • tim wood
    8.7k
    My two cents' worth. You devise a system in which 1+1=2. Then you show your system is isomorphic to arithmetic, that the propositions of the one pass over into being propositions in the other. And QED.

    Not my idea, but from a logic book, title long since forgot.
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