Philosophy
The Epistemology of Disagreement and the Equal Weight View
Quick fact
The equal weight view, defended by philosophers like Richard Feldman and David Christensen, says that when you discover that an epistemic peer disagrees with you, you should treat that peer's opinion as having the same evidential weight as your own—forcing you to lower your confidence, often to the point of suspending judgment or splitting the difference.
Why this is interesting
You and a friend, equally smart and equally informed, look at the same evidence and reach opposite conclusions. Can you both remain fully rational in your belief, or does one of you have to give?