When a person has something to say, we often begin by casting around for why they feel they have to say that thing. At face value, this might be a good response: understanding is helpful. Too often, though, pinning someone to a motive for what they say is merely a convenient way to excuse ourselves from thinking about the content of the speech. After all, if we can detect someone's conflict of interest, then why bother contaminating ourselves with their bias by listening further?

Unfortunately, that calculation is poorly considered and widely lowers the quality of thought, both in individuals and in group discussions. It's so easy to conveniently excuse ourselves this way; pointing to someone else's bias, or even possible or plausible bias, becomes a tactic for overlooking our own, or remaining ignorant, or not parsing evidence and logic.

Even when you firmly believe that you see someone's bias, you really ought to put that belief to one side and consider what they say as if your best friend were saying it. And if we happen to be talking about your best friend already and you just aren't seeing eye to eye, pretend this best friend is, say, a student, and you're looking to compliment something - anything - they're getting right, to encourage them to keep trying.

You will notice this is shockingly unlike how almost everyone goes about it.