502 THE POPULAR SCIENCE MONTHLY. 



in a state of inaction. In the same manner during sleep the Cerebrum 

 may be awake and working, and yet the Sensorium shall be asleep, and 

 we may know nothing of what the cerebrum is doing except by the 

 results. And it is in this manner, I believe, that, having been once set 

 going, and the cerebrum having been shaped, so to speak, in accord- 

 ance with our ordinary processes of mental activity, having grown to 

 the kind of work we are accustomed to set it to execute, the cerebrum 

 can go on and do its work for itself. The work of invention, I am cer- 

 tain, is so mainly produced, from concurrent testimony I have received 

 from a great number of inventors, or what the old English called 

 " makers " what the Greeks called poets, because the word poet means 

 a maker. Every inventor must have a certain amount of imagination, 

 which may be exercised in mechanical contrivance or in the creations 

 of art ; these are inventions they are made, they are produced, we 

 don't know how; the conception comes into the mind we cannot tell 

 whence; but these inventions are the result of the original capacity for 

 that particular kind of work, trained and disciplined by the culture 

 we have gone through. It is not given to every one of us to be an in- 

 ventor. We may love art thoroughly, and yet we may never be able 

 to evolve it for ourselves. So in regard to humor. For instance, there 

 are some men who throw out flashes of wit and humor in their conver- 

 sation, who cannot help it it flows from them spontaneously. There 

 are other men who enjoy this amazingly, whose nature it is to relish 

 such expressions keenly, but who cannot make them themselves. The 

 power of invention is something quite distinct from the intellectual ca- 

 pacity or the emotional capacity for enjoying and appreciating ; but 

 although we may not have these powers of invention, we can all train 

 and discipline our minds to utilize that which we do possess to its 

 utmost extent. And here is the conclusion to which I would lead you 

 in regard to Common-Sense. We fall back upon this, that common- 

 sense is, so to speak, the general resultant of the whole previous action 

 of our minds. We submit to common-sense any questions such 

 questions as I shall have to bring before you in my next lecture ; and 

 the judgment of that common-sense is the judgment elaborated as it 

 were by the whole of our mental life. It is just according as our men- 

 tal life has been good and true and pure, that the value of this acquired 

 and this higher common-sense is reached. We may in proportion I 

 believe to our honesty in the search for truth in proportion as we dis- 

 card all selfish considerations and look merely at this grand image of 

 truth, so to speak, set before us, with the purpose of steadily pursuing 

 our way toward it in proportion as we discard all low and sensual 

 feelings in our love of beauty, and especially in proportion to the 

 earnestness of the desire by which our minds are pervaded always to 

 keep the right before us in all our judgments so I believe will our 

 minds be cleared in their perception of what are merely prudential 

 considerations. It has on several occasions occurred to me to form a 



