Letter 777. To Lady Derby. Down, Saturday [1874?].

If you had called here after I had read the article you would have found a much perplexed man. (777/1. Probably Sir W. Crookes’ "Researches in the Phenomena of Spiritualism" (reprinted from the "Quarterly Journal of Science"), London, 1874. Other papers by Crookes are in the "Proceedings of the Society for Psychical Research.") I cannot disbelieve Mr. Crooke’s statement, nor can I believe in his result. It has removed some of my difficulty that the supposed power is not an anomaly, but is common in a lesser degree to various persons. It is also a consolation to reflect that gravity acts at any distance, in some wholly unknown manner, and so may nerve-force. Nothing is so difficult to decide as where to draw a just line between scepticism and credulity. It was a very long time before scientific men would believe in the fall of aerolites; and this was chiefly owing to so much bad evidence, as in the present case, being mixed up with the good. All sorts of objects were said to have been seen falling from the sky. I very much hope that a number of men, such as Professor Stokes, will be induced to witness Mr. Crooke’s experiments.

(778/1. The two following extracts may be given in further illustration of Darwin’s guiding principle in weighing evidence. He wrote to Robert Chambers, April 30th, 1861: "Thanks also for extract out of newspaper about rooks and crows; I wish I dared trust it. I see in cutting the pages [of Chambers’ book, "Ice and Water"]...that you fulminate against the scepticism of scientific men. You would not fulminate quite so much if you had had so many wild-goose chases after facts stated by men not trained to scientific accuracy. I often vow to myself that I will utterly disregard every statement made by any one who has not shown the world he can observe accurately." In a letter to Dr. Dohrn, of Naples, January 4th, 1870, Darwin wrote: "Forgive me for suggesting one caution; as Demosthenes said, ’Action, action, action,’ was the soul of eloquence, so is caution almost the soul of science.")