1855.] On Mental Education. 477 



he should doubt himself; and, with the desire of rendering 

 himself inaccessible to temptation, takes a counterpoised but 

 unknown quantity of the substance for analysis, that he may 

 remain ignorant of the proportions which he ought to obtain, 

 and only at last compares the sum of his products with his 

 counterpoise. 



The inclination we exhibit in respect of any report or 

 opinion that harmonizes with our preconceived notions, can 

 only be compared in degree with the incredulity we entertain 

 towards everything that opposes them ; and these opposite 

 and apparently incompatible, or at least inconsistent conditions, 

 are accepted simultaneously in the most extraordinary manner. 

 At one moment a departure from the laws of nature is admitted 

 without the pretence of a careful examination of the proof; and 

 at the next, the whole force of these laws, acting undeviatingly 

 through all time, is denied, because the testimony they give is 

 disliked. 



It is my firm persuasion that no man can examine himself in 

 the most common things, having any reference to him personally, 

 or to any person, thought or matter related to him, without 

 being soon made aware of the temptation and the difficulty of 

 opposing it. I could give you many illustrations personal to 

 myself, about atmospheric magnetism, lines of force, attraction, 

 repulsion, unity of power, nature of matter, &c. ; or in things 

 more general to our common nature, about likes and dislikes, 

 wishes, hopes, and fears ; but it would be unsuitable and also 

 unnecessary, for each must be conscious of a large field sadly 

 uncultivated in this respect. I will simply express my strong 

 belief, that that point of self -education which consists in 

 teaching the mind to resist its desires and inclinations, until 

 they are proved to be right, is the most important of all, not 

 only in things of natural philosophy, but in every department 

 of daily life. 



There are numerous precepts resulting more or less from 

 the principles of mental discipline already insisted on as 

 essential, which are very useful in forming a judgment about 

 matters of fact, whether among natural things or between man 

 and man. Such a precept, and one that should recur to the 

 mind early in every new case, is, to know the conditions of the 

 matter respecting which we are called upon to make a judge- 



