364 ZOOLOGICAL PHILOSOPHY 



have found a proof of it in the child which a few minutes after birth 

 tries to suck, and seems to look for its mother's breast, although it 

 can still have no knowledge of it through freshly acquired ideas. I 

 shall refrain from citing the alleged case of a kid which when dragged 

 from its mother's breast selected laburnum from several plants offered 

 it. It is well known that this was a mere imagination, which cannot 

 have been well-founded. 



When once we have recognised that habits are the source of pro- 

 pensities, that continued exercise of these propensities modifies the 

 organisation in a corresponding direction, and that they are then 

 transmitted to new individuals by reproduction, we shall see how the 

 newly born child may try to suck by pure instinct, and may take the 

 breast offered it without having the shghtest idea of it, or carrying out 

 any thought, judgment, or act of will ; and we shall further see that 

 the child performs this action exclusively through the slight emotion 

 which the need raises in its inner feehng, so as to make it act in the 

 direction of an acquired propensity without any previous experience ; 

 we shall see in the same way that the duckling just out of the egg, if 

 it is in the neighbourhood of water, immediately runs to it and swims 

 about on the surface, without having any idea of it or knowing what it 

 does. The animal does not perform this action by any intellectual 

 deliberation, but by a transmitted propensity evoked by its inner 

 feeling without any call upon the intelligence. 



I lay down, then, as a fundamental principle and unquestionable 

 truth, the proposition that there are no innate ideas, but that all ideas 

 whatever spring either directly or indirectly from sensations which 

 are felt and noticed. 



From this principle it follows that the organ of intelligence, being the 

 ultimate perfection which nature has bestowed on animals, can only 

 exist in those which already possess the faculty of feeling. Hence the 

 special organ in which are carried out ideas, judgments, thoughts, 

 etc., only begins to be formed in animals with a highly developed 

 system of sensations. 



All intellectual acts occurring in an individual are due therefore to a 

 combination of the following causes, viz. : 



1. The faculty of feeling ; 



2. The possession of a special organ for intelligence ; 



3. The relations subsisting between this organ and the nervous fluid 

 moving freely about in it ; 



4. Lastly, the fact that the results of these relations are always con- 

 veyed to the nucleus of sensations, and therefore to the individual's 

 inner feeling. 



This is the chain which is in harmony throughout, and constitutes 



