He Used To Say: "Do Not Judge Alone, For None May Judge Alone Except One; And Do Not Say [To Your Fellow Judges], 'Accept My View,' For They [The Majority] Have That Prerogative, Not You."
This principle also applies when judging oneself. A person's self-interest blurs his perspective, so even with regard to one's own affairs, one should always seek the counsel of another.
(Likkutei Sichos, Vol. V, p. 21)