> > Humans define what they want to call ``reality''.
> > Who decide when there exists two conflicting definitions?
> Reality decides what is real. If in your opinion of reality, a certain bridge is
> safe, you are likely to go ahead and use that bridge. And if you are wrong in
> your opinion of reality, you may end up plunging to your death.
> Ultimately, evolution selects for people are good at perceiving reality
> correctly. Since the better you are at perceiving reality, the more likely you
> will survive.
Just wanted to mention that your definition of "Reality" or "Truth" is precisely that of Pragmatism, that is, the theory of knowledge developed by the 19thcentury American philosophers Charles Sanders Peirce, William James, and others, according to which the test of the truth of a proposition is its practical utility; the purpose of thought is to guide action; and the effect of an idea is more important than its origin.
There is a special school of pragmatist thought called "Instrumentalism" which is an even closer fit. This position maintains that the truth of an idea is determined by its success in the active solution of a problem and that the value of ideas is determined by their function in human problem-solving.
All the best,