THE MECHANICAL SYSTEM AND ITS LIMITS 377 



represents an object that can never be entirely replaced 

 by another. Quite apart from the incalculable distance 

 of the stars, one cannot even count in detail the bodies 

 contained within a limited space. No stone is quite 

 like any other, no tree like another, no leaf, indeed, 

 exactly like another. It is, therefore, quite impossible 

 to describe every single thing in the world. 



But even when we abandon the idea of grasping the 

 whole universe, and turn to the study of a small part of it, 

 we encounter insuperable difficulties. Every part of the 

 world, no matter how small, has so many differences 

 latent in it that they cannot be counted. The more 

 thoroughly we study a single body the more vast do we 

 find the number of differences in it. If we continue to 

 analyse a body, we bring to light at each analysis new 

 things that were unknown to us. And as each surface 

 has its colour, and this always differs, we can never 

 exhaust the shades of colour of even the smallest 

 surface. 



This enormous diversity in nature not only prevents 

 science from comprehending the world, but no human 

 being could orientate himself in the world if language 

 did not come to his assistance. Language enables the 

 human mind to take in a large number of details by 

 imposing the same name on them all. The whole 

 infinitely varied population of the earth, differing in 

 each individual, can be grasped by the term "man"; so 

 those predatory animals of the forest, not one of which 

 is quite like another, by the term "wolf." We gather 

 together all the objects in inorganic nature by means of 



