A lie can be caught, because somewhere a person knows the fact it contradicts. A conviction offers no such handle. It arrives feeling like clear sight rather than opinion, it recruits your reasoning to defend it, and it makes contrary evidence look like bad faith. Sincerity is no protection at all, which is why so much damage gets done by the fully convinced.

Keep a short list of things you hold strongly and have never tested. Ask what specifically would have to be true for one of them to be wrong, and whether you would recognise it if it turned up.