This was a comment from a (drunk) atheist (although you’ll get the same thing from lots of sober people):
. . . he repeatedly said he knew God didn’t exist because of life’s general tragedies.
If atheists say they disbelieve because of tragedies, then they weren’t really tragedies. That is, they have no logical grounding to refer to them as truly tragic. They would just be purposeless and meaningless results of Darwinian evolution. That he calls them tragedies is evidence for God, not for the absence of God.
Atheist Bertrand Russell said, ”No one can sit at the bedside of a dying child and still believe in God.” But that proves nothing. The Christian worldview has answers for that situation, no matter how difficult. But what does the atheist say? Tough luck?
Of course we know that many things really are tragedies. But pretending there is no God fixes nothing. You are consciously abandoning the only one who could make sense of the tragedies and provide eternal solutions to our problems.
Ray Comfort defined atheism as:
My own definition of the word “atheist” is someone who pretends that there’s no God. Atheism therefore is the delusion that God doesn’t exist.
I would tweak that this way, a la Romans 1 below: An atheist is someone who suppresses the truth in unrighteousness and pretends that there is no God.
Make no mistake: Romans 1:18–20 For the wrath of God is revealed from heaven against all ungodliness and unrighteousness of men, who by their unrighteousness suppress the truth. For what can be known about God is plain to them, because God has shown it to them. For his invisible attributes, namely, his eternal power and divine nature, have been clearly perceived, ever since the creation of the world, in the things that have been made. So they are without excuse.