144 REASONING. 



previous experiments, the results of which he certainly never framed into 

 any verbal theorems or rules. The same thing may generally be said of 

 any other extraordinary manual dexterity. Not long ago a Scotch manu- 

 facturer procured from England, at a high rate of wages, a working dyer, 

 famous for producing very fine colors, with the view of teaching to his 

 other workmen the same skill. The workman came ; but his mode of pro- 

 portioning the ingredients, in which lay the secret of the effects he pro- 

 duced, was by taking them up in handfuls, while the common method was 

 to weigh them. The manufacturer sought to make him turn his handling 

 system into an equivalent weighing system, that the general principle of 

 his peculiar mode of proceeding might be ascertained. This, however, the 

 man found himself quite unable to do, and therefore could impart his skill 

 to nobody. He had, from the individual cases of his own experience, es- 

 tablished a connection in his mind between fine effects of color, and tactual 

 perceptions in handling his dyeing materials ; and from these perceptions 

 he could, in any particular case, infer the means to be employed, and the 

 effects which would be produced, but could not put others in possession of 

 the grounds on which he proceeded, from having never generalized them 

 in his own mind, or expressed them in language. 



Almost every one knows Lord Mansfield's advice to a man of practical 

 good sense, who, being appointed governor of a colony, had to preside in 

 its courts of justice, without previous judicial practice or legal education. 

 The advice was to give his decision boldly, for it would probably be right ; 

 but never to venture on assigning reasons, for they would almost infallibly 

 be wrong. In cases like this, which are of no uncommon occurrence, it 

 would be absurd to suppose that the bad reason was the source of the 

 good decision. Lord Mansfield knew that if any reason were assigned it 

 would be necessarily an afterthought, the judge being in fact guided by 

 impressions from past experience, without the circuitous process of fram- 

 ing general principles from them, and that if he attempted to frame any 

 such he would assuredly fail. Lord Mansfield, however, would not have 

 doubted that a man of equal experience who had also a mind stored with 

 general propositions derived by legitimate induction from that experience, 

 would have been greatly preferable as a judge, to one, however sagacious, 

 who could not be trusted with the explanation and justification of his own 

 judgments. The cases of men of talent performing wonderful things they 

 know not how, are examples of the rudest and most spontaneous form of 

 the operations of superior minds. It is a defect in them, and often a 

 source of errors, not to have generalized as they went on ; but general- 

 ization, though a help, the most important indeed of all helps, is not an 

 essential. 



Even the scientifically instructed, who possess, in the form of general 

 propositions, a systematic record of the results of the experience of man- 

 kind, need not always revert to those general propositions in order to ap- 

 ply that experience to a new case. It is justly remarked by Dugald Stew- 

 art, that though the reasonings in mathematics depend entirely on the 

 axioms, it is by no means necessary to our seeing the conclusiveness of 

 the proof, that the axioms should be expressly adverted to. When it is 

 inferred that AB is equal to CD because each of them is equal to EF, the 

 most uncultivated understanding, as soon as the propositions were under- 

 stood, would assent to the inference, without having ever heard of the gen- 

 eral truth that " things which are equal to the same thing are equal to one 

 another." This remark of Stewart, consistently followed out, goes to the 



