Introduction to Philosophy/Pragmatism
Pragmatism is a philosophy that was developed and passed on by Peirce, Quine, James, and others.
The Correspondence Theory of Truth, which was held by Aristotle among others, holds that when we say something is true, this means that my understanding of reality corresponds with reality. So if I say that the Sun revolves around the Earth, it is not true because this does not correspond to reality. On the other hand, a Pragmatist would say that if it "works" for you, if it does not make your life problematic and has no significant impact on your life, then it is "true" in the sense that it works; it's pragmatic. This is similar to the perspectivist view adopted by Nietzsche.
See William James (1842-1910):