The first law for the historian is that he shall never dare utter an untruth. The second is that he shall suppress nothing that is true. Moreover, there shall be no suspicion of partiality in his writing, or of malice.
It is the mark of an educated mind to rest satisfied with the degree of precision which the nature of the subject admits and not to seek exactness where only an approximation is possible.
When in doubt, tell the truth. That maxim I did invent, but never expected it to be applied to me. I did say, "When you are in doubt," but when I am in doubt myself I use more sagacity.
When a thing is said to be not worth refuting you may be sure that either it is flagrantly stupid - in which case all comment is superfluous - or it is something formidable, the very crux of the problem.