THE CEREBRUM, AND ITS FUNCTIONS. 785 



strongly directed a short time before sleep supervenes, are fixed upon the mind 

 with remarkable force ;* a fact that seems to indicate that these impressions 

 modify the nutrition of the Brain (which is taking place with peculiar activity 

 during the state of mental repose), and that the peculiar readiness with which 

 they may be recalled thus depends upon organic changes of which we are un- 

 conscious, rather than upon any intentional strengthening of the links of asso- 

 ciation. 



814. By Attention to our own mental states and operations, a class of Ideas 

 is generated, of a very different character from those which are called up by ex- 

 ternal objects ; and these, being entirely dependent upon the operation of the 

 Intellectual powers, and having no relation to sensations except as the original 

 springs of those operations, may be termed 'intellectual Ideas, in contradistinction 

 to the sensational Ideas. The former, like the latter, become the subjects of the 

 associating tendency ; and thus are combined in Trains of Thought. Some of these 

 intellectual ideas appear to be so necessarily excited by mental operations, even of 

 the simplest kind, and to be so little dependent on individual peculiarities, either 

 inherent or acquired, that they take rank as fundamental axioms or principles of 

 Human Thought. Such are the belief in our ovrnpresent existence, or the faith 

 which we repose in the evidence of Consciousness : this idea being necessarily 

 associated with every form and condition of mental activity : the belief in OUT past 

 existence, and in our personal identity so far as our memory extends, which is 

 necessarily connected with the act of Recollection ; with this, again, is connected 

 the general idea of Time : the belief in the external and independent existence of 

 the causes of our sensations, which results from the direction of the mind to the 

 Perceptional ideas orginating in them; with this is connected the general idea 

 of Space : the belief in the existence of an efficient cause for the changes which 

 we witness around us, which springs from the perception of those changes ; 

 whence is derived our idea of Power : the belief in the stability of the order of 

 nature, or in the invariable sequence of similar effects to similar causes, which 

 also springs directly from the perception of external changes, and seems prior 

 to all reasoning upon the results of observation of them (being observed to 

 operate most strongly in those whose experience is most scanty, and in relation 

 to subjects that are perfectly new to them); but which is the foundation of all 

 applications of our own experience or that of others, to the conduct of our lives 

 or to the extension of our knowledge : lastly, the belief in our own free will, in- 

 volving the general idea of Voluntary Power; which is in like manner a direct 

 result of our internal perception of those mental changes which are excited by 

 sensations. Hence it is evident that " the only foundation of much of our belief, 

 and the only source of much of our knowledge, is to be found in the constitution 

 of our own minds;" but it must be steadily kept in view, that these fundamental 

 axioms are nothing else than expressions of the general fact, that the ideas in 

 question are uniformly excited (in all ordinarily constituted minds at least) by 

 simple Attention to the changes in which they originate. Among those ele- 

 mentary modes of thought, which arise out of the constitution of our own minds, 

 we must also rank the ideas of Truth, Beauty, and Right, which intuitively present 

 themselves to our consciousness, in connection with certain objects or occurrences 

 respectively adapted to excite them ; the first connecting itself especially with 

 the operations of the Reason, the second with the production of those states of 

 feeling which are termed Sentiments, and the third with the determinations of 

 the Will in the guidance of conduct. Truth may be defined to be an apprehension 

 of the relations of things as they actually exist ; and the conception of truth, 



1 Thus it is well known to schoolboys who have a task to commit to memory, that if 

 they can put it together correctly, however hesitatingly, over night, they can generally 

 repeat it fluently in the morning. . 



50 



