228 THE CASE AGAINST EVOLUTION 



inhibits the reactive power of the sense in question, the dura- 

 tion of this repair work being determined by the amount of 

 neural decomposition caused by the reaction of the sense to 

 the previous stimulus. When, therefore, a weaker stimulus 

 supervenes in immediate succession to a stronger one, the sense 

 is incapable of perceiving it. All organic activity, in short, 

 such as sense-perception and imagination, is rigidly regulated 

 by the metabolic law of waste and repair. 



With the intellect, however, the case is quite different. The 

 intellect is neither debilitated nor stupefied by the discovery of 

 truths that are exceptionally profound, or unusually abstruse, 

 or strikingly evident; nor is it temporarily incapacitated 

 thereby from understanding simpler, easier, or less evident 

 truths. On the contrary, the more comprehensive, the more 

 penetrating, the more perspicuous, the more sublime our intel- 

 lectual vision is, so much the more is our intellect invigorated 

 and enthused in its pursuit of truth, and its knowledge of the 

 highest truths renders it not less, but more, apt for the under- 

 standing of simple and ordinary truths. Obviously, then, the 

 intellect is not bound to a corruptible organ like the senses, 

 but has for its subject a spiritual principle that is intrinsically 

 independent of the organism. 



In opposition to this contention, it may be urged that a pro- 

 longed exercise of intellectual activity results in the condition 

 commonly known as brain-fag. But this fatigue of the brain 

 is not, as a matter of fact, the direct effect of intellectual 

 activity; rather it is the direct effect of the activity of the 

 imagination, and only indirectly the effect of intellectual 

 thought. The intellect, as we have seen, requires a constant 

 flow of associated and aptly coordinated imagery as the sub- 

 strate of its contemplation. Now, the imagination, which 

 supplies this imagery, is a cerebral sense, whose activity is 

 directly proportionate to, and commensurate with, the meta- 

 bolic processes at work in the cortical cells. Its exercise is 

 directly dependent upon the energy released by the decompo- 

 sition of the cerebral substance. Prolonged activity of the 



