What is the best method to prove something is true? Empirical evidence? Statistics? some other form of measurement?

In this age of absolute relativism where many young minds go into universities grounded in what they know to be true, but come out of after their 'education' and cant tell if their dinner that evening is made of atoms or 1s & 0s or if its racist or not or some other contrived detachment from reality the likes of which Descartes would be proud.