From time to time, I refer to “Mr. X”.
Mr. X is a close and trusted friend, highly educated, thoughtful, insightful, and pragmatic. Most importantly, he does not necessarily agree with many of my positions. BUT, he’s intellectually honest, and will bend to rational argument. So, he keeps me honest, and I value his opinion. If I can’t convince Mr. X, then I probably need to keep perfecting my thoughts.