the specific atom doesn't matter
No, it does very much matter if you're going to try to say "
every event has a cause." If every event has a cause, no random events can occur. I pointed out a random event. Therefore, some events occur without cause.
If your entire world was an atom - if only that one atom was all the atoms you had ever seen - and it decayed suddenly, wouldn't you say that it occured without cause?
The weak force explains the
general phenomenon of beta decay for all atoms, but it doesn't explain why, at any one moment, one atom decayed while another did not. Hence, that specific atom's decay was random and uncaused. Ergo, causality is not a universal law; random, causeless events can and do occur.