A conviction becomes more trustworthy when its holder can describe the strongest difficulty facing it.

Someone who can state the best case against their own position has actually travelled with it. Certainty that has never met an objection is cheap, and it tends to give itself away by caricaturing the other side. The test is not how confident a person sounds but whether they can name the difficulties accurately.

Take a belief you hold firmly and write down the most serious objection to it, in a form its holder would accept. If you cannot, that is worth knowing before your next argument about it. Ask someone who disagrees whether you got them right.