CONSCIOUSNESS DEPENDENT UPON CHANGE. 37 



sciousness is in ourselves, and is only referred to external 

 causes by the aid of the intellect. 



A thing cannot act alone, or upon itself; perfect 

 sameness is inert, it cannot move. To produce conscious- 

 ness there must be a difference^ a thing acting and a 

 thing acted upon the latter being the human brain. A 

 photographic plate cannot take an image of itself, neither 

 can the cerebral substance which perceives perceive itself 

 the two actions are simultaneously incompatible; we 

 cannot think, and at the same time think of that act of 

 thought. Perfect continuity, sameness, or non-variation 

 of cause, has no effect upon our perceptive powers, and 

 therefore we are unable to perceive directly time, space, 

 force, or motion in themselves ; we feel not the uniform 

 pressure of the atmosphere, nor the motion of the earth. 

 The dependence of consciousness upon change of impres- 

 sion is largely proved by the fact, that whilst the mind is 

 highly incapable of completely realising ultimate ideas ; 

 or those of the great static uniformities of space, time, 

 and infinite potential power; or the great cause of all 

 things it is quite capable of perceiving those of sequences 

 or of orders of succession of mental impressions, because 

 in the latter case only is there great and rapid mental 

 change. Also, although we can but little conceive ideas 

 of the essential natures of the modes of energy which 

 produce physical and chemical effects, we can very much 

 more completely realise the order of effects which those 

 forces produce ; and our conceptions of ultimate power, 

 of causation, and of the relations of cause and effect, 

 depend upon this ability. ' There are many things which 

 we neither know nor can know in themselves, that is, in 

 their direct and immediate relation to our faculties of 

 knowledge, but which manifest themselves through the 

 medium of their effects. Consciousness cannot exist in- 



