Why? The scientific method is not designed to produce what's true, it's designed to simply eliminate what's not true. Even the lowest level of science: math has a set of axioms from which everything else is built. We think they're true but we've also shown rigorously that you can't prove an axiom and they might be shown to be wrong. For example, Euclid's fifth postulate stood for two thousand years. It stated that non-parallel lines would meet at some point and conversely that parallel lines would never meet. From 300BC to 1830AD this was believed to be true.