404 ZOOLOGICAL PHILOSOPHY 



causing some action, takes its origin from the needs and propensities 

 which arouse immediately the individual's inner feeling and make him 

 act, without any choice or deliberation, or, in short, any participation 

 of the intellect. 



The actions of certain animals are therefore sometimes based on 

 rational determinations, but more often on an instinctive force. 



If we pay attention to the facts and arguments presented in the 

 course of the present work, we shall perceive that there must be animals 

 which have neither reason nor instinct, such as those which are destitute 

 of the faculty of feeling ; that there must be others which have instinct 

 but possess no degree of reason, such as those which have a sensitive 

 system, but lack the organ for intelUgenee ; lastly, that there must 

 be others again which have instinct together with some degree of reason, 

 such as those which possess a system for sensations and another for 

 acts of the understanding. The instinct of these last is the source 

 of nearly all their actions, and they rarely make use of such degrees 

 of reason as they possess. Man, who comes next, also has instinct 

 which in certain circumstances makes him act ; but he is capable of 

 acquiring much reason, and of using it to control the greater part of 

 his activities. 



Besides the individual reason of which I have been speaking, there is 

 estabhshed, in every country and region of the earth, in proportion 

 to the knowledge of the men who hve there and to certain other factors, 

 a public reason, which is almost universal, and which is upheld until 

 new and sufficient causes operate to change it. In both cases, the 

 individual and the pubhc reason are always constituted by a certain 

 degree of rectitude in the judgments. 



It is true that in a society or nation, errors and false behefs may 

 be as much matters of general assent as ascertained truths ; so that 

 various errors, prejudices, and truths go to make up the degree of 

 rectitude of judgment, both in individuals and in the received 

 opinions of societies, groups, and nations, according to the age or 

 period considered. 



We have therefore to recognise different stages of advance in the 

 reason of a people or society, as in that of an individual. 



Men who strive in their works to push back the limits of human 

 knowledge know well that it is not enough to discover and prove a 

 useful truth previously unknown, but that it is necessary also to be 

 able to propagate it and get it recognised ; now both individual 

 and public reason, when they find themselves exposed to any alteration, 

 usually set up so great an obstacle to it, that it is often harder to secure 

 the recognition of a truth than it is to discover it. I shaU not dwell 

 on this subject, because I know that my readers will see its imphca- 



