“Outward judgment often fails, inward judgment never.”

Source: The 7 Habits of Highly Effective People: Powerful Lessons in Personal Change

As quoted in Leo Szilard : His Version of the Facts, edited by S. R. Weart and G. W. Szilard, in Bulletin of the Atomic Scientists (February 1979), Vol. 35, No. 2, p. 38

Source: 1920s, Process and Reality: An Essay in Cosmology (1929), p. 259.
Variant: It is more important that a proposition be interesting than that it be true. This statement is almost a tautology. For the energy of operation of a proposition in an occasion of experience is its interest, and its importance. But of course a true proposition is more apt to be interesting than a false one.
As extended upon in Adventures of Ideas (1933), Pt. 4, Ch. 16.
Context: Some philosophers fail to distinguish propositions from judgments; … But in the real world it is more important that a proposition be interesting than that it be true. The importance of truth is that it adds to interest.

Address at the dedication of the Northwestern University Law School Building, Chicago, Illinois (20 October 1902); republished in Holmes' Collected Legal Papers (1937), p. 272.
1900s

"Zeitgeist and Poltergeist; or, Are Movies Going to Pieces?" http://www.paulrossen.com/paulinekael/aremoviespieces.html (December 1964), from I Lost It at the Movies (1965).

Adverbs (2006), Judgmentally

Conversation at a dinner in 10 Downing Street (24 September 1791), quoted in George Pellew, The Life and Correspondence of the Right Hon. Henry Addington, First Viscount Sidmouth, Volume I (London: John Murray, 1847), p. 72.

Source: The Mike Wallace Interview (1958)