Recently, I was listening to an episode of the excellent medical history podcast Sawbones on the history of mumps, as well as the development of the MMR vaccine. The hosts wrapped up with a plea to call out anti-vaxxers any time they speak up, to showcase their ignorant and dangerous ideas for what they are. At one point, Sydney McElroy pointed out that this was an issue in which providing equal consideration to both sides was a disastrous mistake. There's the truth (vaccines don't cause autism), and there's the lie (they do), and giving the lie consideration as an equal half of a debate legitimizes it in an extremely dangerous way. I agree with this wholeheartedly.
This also happens to be the way that I feel about a lot of issues. Anti-abortion activists, white nationalism, objectivism, "family values" organizations, climate change deniers, etc. are all peddling dangerous ideas that have zero basis in reality, and approaching those debates as, "Well, there are two sides, and we should consider each side equally," is not the right approach. But where does that leave us? How do I engage with someone who genuinely believes in something so anathema to reason?
I don't want the answer to be, "Just write them off. You'll never convince them, and there's no point in trying." First, there are way too many people who believe these dangerous ideas, and leaving them to fester in that toxicity leaves them free to inflict those ideas on their communities. Second, many of us have family members in that camp, or other people we're not willing to give up on. So how do I even begin having a conversation that leads in the right direction?