What do I care, said Epictetus, whether everything is composed of atoms or indivisibles or fire & earth? Is it not enough to study the nature of good & evil, the limits of our desires & aversions, and also of our impulses to act and avoid, and, employing these as rules, to direct the affairs of our life and dismiss the things that are beyond us?
Stobaeus II. 1, 31 ( Fragment 1, Schenkl )
Epictetus is not in fact as contemptuous of physics as this sounds, but he clearly believes that the most important questions, about how we should lead our lives, do not depend our scientific conjectures of the world.
But suppose we recast his challenge in terms of the modern biological sciences: "what do I care about how a human being comes to be from its genome? Or about what chemistry & neurophysiology underlie the emotions and choices and beliefs that our brains create? Can we still dismiss scientific knowledge of this sort as irrelevant to how we should guide the course of our life?" ( This is unfair if pressed as a criticism of Epictetus' dismissal of physical speculation. He has no experience of scientific inquiry as we know it. )