“You don’t seem to give much thought to the matter in hand,” I said at last, interrupting Holmes’s musical disquisition.
“No data yet,” he answered. “It is a capital mistake to theorize before you have all the evidence. It biases the judgement.”Arthur Conan Doyle (1859-1930) British writer and physician
Story (1886-04), “A Study in Scarlet,” Part 1, ch. 3, Beeton’s Christmas Annual, Vol. 28 (1887-11-21)
(Source)
