Attacking a person, motive, or source

Who makes a claim can affect how we assess their testimony. Relevant knowledge, a record of accuracy, and possible conflicts of interest can all matter. But personal information does not automatically answer the claim itself.

This lesson distinguishes three related mistakes: attacking the person, dismissing an argument because of a motive, and judging an idea only by its origin. The shared problem is letting a fact about the speaker or source replace examination of the reasons.