“If God indeed does exist, what is the source of evil? But if He does not exist, what is the source of good?” -- Boethius, The Consolation of Philosophy, Book 1, Chapter 4
Some people consider the former question more telling, others the latter. But the latter question ought to have priority over the former, just because good has priority over evil.
This proposition is called the privation theory of evil. To have a lapse of sanity, which is bad, one must already have a mind, which is good; to have a disease, which is bad, one must already have a body, which is good. In general, the only way to get any evil whatsoever is to take something good and ruin it.
So Boethius has not just answered a question with a question, which might be dismissed as a mere debater’s trick. He has answered a good question with a better one.