It took the medical community 20 years to adopt the practice of washing their hands after Ignaz Semmelweis discovered that the practice will dramatically reduce the spread of infection.
Even with proof, it still may not be enough to change someone’s mind. It all depends on what the person you are talking to chooses to put their faith in.
When we have a difficult time suspending belief to discuss a world of possibility, we are not having a discussion around truth but rather beliefs.
But it’s also worth remembering, there are systems that are totally true and not provable.