OF THE UNDERSTANDING 365 



the developed physical cause of the most wonderful of natural 

 phenomena. 



To set up a reasonable opposition to the views stated above, it would 

 be necessary to show that the harmony existing throughout the nervous 

 system is not capable of producing sensations and the individual's 

 inner feeling ; that intellectual acts, such as thoughts, judgments, 

 etc., are not physical acts, and do not result immediately from relations 

 between a subtle agitated fluid and the special organ containing it ; 

 lastly, that the results of these relations are not transmitted to the 

 individual's inner feehng. Now the physical causes named above are 

 the only ones that can possibly give rise to the phenomena of intelli- 

 gence. If therefore the existence of these causes is denied, and if 

 consequently it is denied that the resulting phenomena are natural, 

 it will then be necessary to seek another source of these phenomena 

 outside nature. It will be necessary to substitute for the physical 

 causes rejected, fantastic ideas of our own imagination, ideas that are 

 always baseless since it is quite obvious that we can have no other 

 positive knowledge than that derived from the actual objects which 

 nature presents to our senses. 



Since the marvels which we are investigating, and whose causes 

 we are seeking, are based upon ideas, and since in acts of intelUgence 

 we are dealing only with ideas and operations on ideas ; before enquir- 

 ing what ideas themselves are, let us illustrate the gradual formation 

 of the organs which give rise firstly to sensations and the inner feeling, 

 then to ideas and, lastly, to the operations performed upon them. 



The very imperfect animals of the earher classes, having no nervous 

 system, are simply irritable and merely have habits without feehng 

 any sensations or ever forming ideas. But the less imperfect animals, 

 which have a nervous system without, however, the organ of in- 

 telligence, have instinct, habits and propensities and feel sensations, 

 while yet forming no ideas. I venture to affirm that where there is 

 no organ for a faculty, that faculty cannot exist. 



Now if we admit that every idea originates from a sensation, which 

 indeed cannot seriously be disputed, I hope to show that it does not 

 follow that every sensation necessarily yields an idea. The organisa- 

 tion must have reached a state favourable to the formation of the idea, 

 and, moreover, the sensation must be accompanied by a special effort 

 of the individual, in short, by a preparatory act which renders the special 

 organ of intelligence capable of receiving the idea, that is, of retaining 

 impressions. 



Indeed, if it is true that in creating organisation, nature necessarily 

 began by forming it in extreme simphcity without the intention of 

 giving living bodies any other faculties than those of feeUng and 



