Theists often argue that "atheists can't prove God doesn't exist". This often turns into a back and forth of atheists saying "but that's because you can't prove a negative". Etc...
I have a suggestion for such an incident. Ask them if they agree that one should be "innocent until proven guilty". Ask if they believe that is a good general rule and an important staple of the judicial system.
We don't believe someone did something... UNTIL we have substantial evidence.
So could that imply that anyone who believes in something without evidence might as well disagree with the judicial system's "innocent until proven guilty"? Is this NOT the same thing as a theist disbelieving something cause it can't be disprove? I suppose one plays on the playingfields of the gods, which we shouldn't understand but ultimately in daily life... but my point is that in everyday life we don't believe in things without proof. And why should we with religion.
What are other common methods of coming to conclusions without evidence?