2 g 2 THE POPULAR SCIENCE MONTHLY. 



produced by our own unclearness of thought for a character of the 

 object we are thinking. Instead of perceiving that the obscurity is 

 purely subjective, we fancy that we contemplate a quality of the 

 object which is essentially mysterious ; and if our conception be after- 

 ward presented to us in a clear form we do not recognize it as the 

 same, owing to the absence of the feeling of unintelligibility. So 



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Fig. 1. Fig. 2. 



long as this deception lasts, it obviously puts an impassable barrier 

 in the way of perspicuous thinking; so that it equally interests the 

 opponents of rational thought to perpetuate it, and its adherents to 

 guard against it. 



Another such deception is to mistake a mere difference in the 

 grammatical construction of two words for a distinction between the 

 ideas they express. In this pedantic age, when the general mob of 

 writers attend so much more to words than to things, this error is 

 common enough. When I just said that thought is an action, and 

 that it consists in a relation, although a person performs an action 

 but not a relation, which can only be the result of an action, yet 

 there was no inconsistency in what I said, but only a grammatical 

 vagueness. 



From all these sophisms we shall be perfectly safe so long as we 

 reflect that the whole function of thought is to produce habits of ac- 

 tion ; and that whatever there is connected with a thought, but irrele- 

 vant to its purpose, is an accretion to it, but no part of it. If there 

 be a unity among our sensations which has no reference to how we 

 shall act on a given occasion, as when w T e listen to a piece of music, 

 why we do not call that thinking. To develop its meaning, we have, 

 therefore, simply to determine what habits it produces, for what a 

 thing means is simply what habits it involves. Now, the identity of 

 a habit depends on how it might lead us to act, not merely under such 

 circumstances as are likely to arise, but under such as might possibly 



