376 ZOOLOGICAL PHILOSOPHY 



complex idea is always a judgment ; and this judgment itself is either 

 a consequence or a determination of a relationship. Now this act 

 appears to me to be due to the resultant movement of the nervous 

 fluid which has been broken up by the inner feeling into separate 

 streams, each of which traverses previously made impressions of certain 

 ideas, and thence undergoes special kinds of modifications in its move- 

 ments. When the streams reunite their individual movements are 

 then combined into this resultant movement. 



It is then by means of this movement of the nervous fluid, which 

 is really due to compared ideas or to relations between them, that the 

 subtle fluid makes its impressions on the organ and at the same 

 moment transfers the effect to the individual's inner feeling. 



Such is in my opinion the physical cause and precise mechanism 

 which give rise to the formation of all kinds of complex ideas. These 

 complex ideas are quite distinct from simple ideas, since they do not 

 result from any immediate sensation or impression on any of our senses, 

 but originate from several ideas already impressed, and, further, are 

 exclusively due to an act of the understanding in which the sensitive 

 system has no share. 



There is this difference between the act of understanding which forms 

 a judgment whence arises a complex idea, and that called a recollection 

 or act of memory, which merely consists in recalling ideas to the 

 individual's inner feeling : that in the former case the ideas employed 

 take part in an operation resulting in a new idea, whereas in the second 

 case the ideas employed take part in no operation, give rise to no new 

 idea, but merely become present to the individual's consciousness. 



If it is true that the emotions of our inner feeling give us the faculty 

 and power of acting, and that they enable us to put our nervous fluid in 

 motion and direct it over the impressions of various ideas made upon 

 different parts of the recipient organ, it is obvious that this subtle 

 fluid, while passing over the tracings of any idea, will undergo a special 

 modification in its mode of agitation. We may suppose that, if the 

 nervous fluid simply brings back this special modification of its agitation 

 to the individual's inner feeling, it only makes the idea perceptible or 

 present to the individual's consciousness ; but if the fluid, instead of 

 merely passing over the tracings or image of a single idea, divides into 

 several streams, each of which travels over some individual idea, and 

 if the streams then all reunite, the resultant movement of the combined 

 fluid will impress on the organ a new and complex idea, and will then 

 transfer its effect to the individual's consciousness. 



If we form complex ideas out of pre-existing simple ideas, we shall 

 have, as soon as they are impressed on our organ, complex ideas of the 

 first order : now it is obvious that if we compare together several 



