Mind depends upon physical conditions. 99 



Whilst copious evidence is available to shew that the 

 mind is excitable by physical causes, no more conclu- 

 sive proof exists that a mental impression arises 

 without a natural cause, than that a physical one, such 

 ,as a photographic impression, arises in that way. 

 Abundant evidence of non-creation of ideas out of 

 nothing might be adduced ; even imagination and 

 invention are subject to this limit, because an un- 

 limited number of new conceptions cannot be formed 

 from a limited number of previous ideas. 

 , The dependence of the mind (like any other mode 

 of energy) upon physical conditions, is further proved 

 by the fact that the mental and moral states of a 



'. man are largely governed by sensation ; if the latter 

 is unhealthy it makes the mind so, and it makes some 

 difference what the part of the body is in which the 

 sensation exists ; most commonly it is the viscera. 

 The mind is also intimately dependent upon the 

 physical condition of the brain, and is largely affected 

 by the quantity and quality of the blood in that 

 organ. 



The most fundamental principle which pervades 

 every one of the sciences, and agrees with the actions 

 of every natural form of energy without exception, 



/ including mind, is, that of consistency or non-contra- 

 diction. No machine or scientific apparatus of any 

 / kind can perform two contradictory acts at the same 

 time. It is both a physiological and psychological 

 fact, that we cannot experience two contradictory 

 -sensations, nor perceive two contradictory ideas at the 



M M 



