Is there such a thing as ultimate truth, or is truth just a matter of personal opinion? The ancient Greek sophist Protagoras famously said that “man is the measure of all things.” The poem “Late Lament” at the end of the Moody Blues song “Nights in White Satin” repeats the same idea: “But we decide which is right, and which is an illusion.” If I just make up my own values, then it would seem that nothing obligates me to respect them. Indeed, why should I think I'm obligated to have values at all? Against Protagoras, Socrates and Plato raised the question as to whether we should be looking to something outside ourselves for guidance. But if so, how can I determine what that is or where it comes from? Religious traditions recommend belief in gods, heroes, and demons. Is it realistic to look for anything more than whatever we each personally decide to believe in, or does our ability to think and reason offer an alternative to belief? Or do we need some kind of hybrid born of both?