MIND, BRAIN AND BIOCHEMISTRY 389 



A second line of reflection leads to the relationship between 

 body and the principle of life. If organic activity is possible 

 only when life is present, then the principle of life is not separate 

 from a living organism. In fact, it is by reason of the life- 

 principle that the body is living and biologically organic. In 

 other words, the life-principle activates the matter in giving 

 it organic life and unity of being. In this context, the material 

 mass of the body and the chemical compounds are recipients 

 of activation; they are capacities, potentialities for actual life. 

 When Aristotle designated this ' matter ' as a passive capacity, 

 it was in relation to the activizing principle of ' form.' Just as 

 human life cannot be understood except in relation to an 

 organism, so an organic body cannot be understood without 

 reference to the life-principle, commonly called a soul. It would 

 be absurd to think that the soul is some kind of unknown 

 chemical substance. Rather the soul is that by which every 

 chemical compound in an organism is living. Hence it is futile 

 to search for a ' soul ' through chemical analysis. 



Second, it is important to note that there are important 

 differences between a human soul and a purely animal soul, 

 even though both are life-principles informing a highly complex 

 organism. The principle of human life performs functions, such 

 as thinking, willing, idealizing and reflecting, which are not 

 limited to space-time patterns. This is not to say that thinking 

 and willing are activities performed outside of space and time, 

 but only that they are not limited as sensations and emotions 

 are. In the Aristotelian tradition this transcendence of thinking 

 and willing shows the spiritual nature of mind and will. The 

 non-limited behavior of mind and will is, of course, derived 

 from the same life-principle which animates the human body. 

 Consequently the single life-principle in man is the unique 

 source of both organic life in the body and of mental life trans- 

 cending the limitations of space-time patterns. There can be 

 no doubt that man's soul is an extraordinary type of reality: 

 it animates an organic body, yet its nature and functions are 

 not entirely limited to the biochemistry of the body. 



