18 THE PHILOSOPHY OF BIOLOGY 



Thus we decompose our stream of consciousness 

 into a series of quantitatively different and qualitatively 

 different things, upon each of which we confer in- 

 dependent existence. We attribute to these different 

 aspects of our consciousness extension, but the ex- 

 tension is due only to our analysis ; for the qualities 

 of pitch, loudness, colour, odour, etc., which we dis- 

 entangle from each other, did not exist apart from each 

 other, any more than do the sine and cosine curves 

 into which we decompose an arbitrarily drawn curved 

 line. The multiplicity of our consciousness is intensive, 

 like the multiplicity that we see to exist in the abstract 

 number ten. This number stands for a group of things, 

 but its multiplicity is intensive and only exists because 

 we are able to subdivide anything in thought to an 

 indefinite extent. Now, so far we have only separated 

 what we agree to regard as the elemental parts of our 

 general perception of the environment, but it is to be 

 noted that we have not given to these elements anything 

 like spatial extension. 



We may, if we like, regard our intuition of space 

 as that of an indefinitely large, homogeneous, empty 

 medium which surrounds us and in which we may, 

 in imagination, place things. So regarded it is difficult 

 to see in what way our notion of space differs from our 

 idea of " nothing," a pseudo-idea incapable of analysis, 

 except into the idea of something which might be 

 somewhere else. The more we think about it the more 

 we shall become convinced that space, that is the 

 " form ' of space, represents our actual or potential 

 modes of motion, that is, our powers of exertional 

 activity. Space, we say, has three dimensions ; in 

 all our analysis of the universe, and of the activities 

 that we can perceive in it, this idea of movement in 

 three dimensions, forward and backward, up and down, 



