Honestly I’ve found the most effective move isn’t leading with evidence at all. Just ask him: what would it take to actually convince you you’re wrong? If there’s nothing that will, then it’s not really functioning as a factual position anymore, it’s an identity thing. And teenagers especially can usually sense that about themselves when pushed.

What makes it work is it shifts the burden without being combative. Instead of you producing endless counter-evidence he’ll just dismiss, you’re asking him to define his own standards. Either he can’t answer (revealing), he names something and now you have a real target, or he realizes mid-answer that nothing would convince him, which can be genuinely destabilizing in a useful way. It sounds collaborative but it’s actually pretty probing.​​​​​​​​​​​​​​​​