230 THE CASE AGAINST EVOLUTION 



intellectual thought itself is steady, lucid, and continuous. 

 The intensity of thought does not vary with the fluctuations of 

 neural metabolism, and may reach a maximum without 

 involving corresponding fatigue in the brain. The brain-fag, 

 therefore, which results from study does not correspond to the 

 height of our intellectual vision, but is due to the intensity of 

 the concomitant imaginative process. 



The intellect, therefore, is not subject to the metabolic laws 

 which rigidly regulate organic functions like sense-p€rception 

 and imagination. Man's capacity for logical thought is fre- 

 quently unaffected by the decline of the organism which sets 

 in after maturity. All organic functions, however, such as 

 sight, hearing, sense-memory, are impaired in exact proportion 

 to the deterioration of the organism, which is the inevitable 

 sequel of old age. The intellectual powers, on the contrary, 

 remain unimpaired, so long as the cortex is sound enough to 

 furnish the required minimum of imagery, upon which intel- 

 lectual activity is objectively dependent. There are, in fact, 

 many cases on record where men have remained perfectly sane 

 and rational, despite the fact that notable portions of the 

 cerebral cortex had been destroyed by accident or disease 

 {e.g., tumors). Intellectual thought, therefore, is a super- 

 organic function, having its source in a spiritual principle and 

 not in a corruptible organ. 



Such is the spiritualism of Aristotle. That this conception 

 differs profoundly from the ultra-spiritualism of Descartes, it 

 is scarcely necessary to remark. The position assumed by the 

 latter was always untenable, but it is now, more than ever, 

 indefensible in the face of that overwhelming avalanche of 

 facts whereby modern physiological psychology demonstrates 

 the close interdependence and correlation existent between 

 psychic and organic states. Such facts are exploited by ma- 

 terialists as arguments against spiritualism, though it is evi- 

 dent that they have force only against Cartesian spiritualism, 

 and are bereft of all relevance with respect to Aristotelian 

 spiritualism, which they leave utterly intact and unscathed. 



