Apart from what is technical, method is only the reduplication of common sense, and is best acquired by observing its use by the ablest men in every variety of intellectual employment #70. Bentham acknowledged that he learned less from his own profession than from writers like Linnaeus and Cullen; and Brougham advised the student of Law to begin with Dante. Liebig described his Organic Chemistry as an application of ideas found in Mill's Logic, and a distinguished physician, not to be named lest he should overhear me, read three books to enlarge his medical mind; and they were Gibbon, Grote, and Mill. He goes on to say, "An educated man cannot become so on one study alone, but must be brought under the influence of natural, civil, and moral modes of thought." #71 I quote my colleague's golden words in order to reciprocate them. If men of science owe anything to us, we may learn much from them that is essential #72. For they can show how to test proof, how to secure fulness and soundness in induction, how to restrain and to employ with safety hypothesis and analogy. It is they who hold the secret of the mysterious property of the mind by which error ministers to truth, and truth slowly but irrevocably prevails #73. Theirs is the logic of discovery #74, the demonstration of the advance of knowledge and the development of ideas, which as the earthly wants and passions of men remain almost unchanged, are the charter of progress and the vital spark in history. And they often give us invaluable counsel when they attend to their own subjects and address their own people. Remember Darwin taking note only of those passages that raised difficulties in his way; the French philosopher complaining that his work stood still, because he found no more contradicting facts; Baer, who thinks error treated thoroughly nearly as remunerative as truth, by the discovery of new objections; for, as Sir Robert Ball warns us, it is by considering objections that we often learn #75. Faraday declares that "in knowledge, that man only is to be condemned and despised who is not in a state of transition." And John Hunter spoke for all of us when he said: "Never ask me what I have said or what I have written; but if you will ask me what my present opinions are, I will tell you."