126 MYSTICISM AND LOGIC 



survives in Descartes and in a somewhat modified form 

 in Spinoza, but with Leibniz it begins to disappear, and 

 from his day to our own almost every philosopher of note 

 has criticised and rejected the dualism of common sense. 

 It is my intention in this article to defend this dualism ; 

 but before defending it we must spend a few moments on 

 the reasons which have prompted its rejection. 



Our knowledge of the material world is obtained by 

 means of the senses, of sight and touch and so on. At 

 first it is supposed that things are just as they seem, but 

 two opposite sophistications soon destroy this naive 

 belief. On the one hand the physicists cut up matter 

 into molecules, atoms, corpuscles, and as many more 

 such subdivisions as their future needs may make them 

 postulate, and the units at which they arrive are un- 

 commonly different from the visible, tangible objects ot 

 daily life. A unit of matter tends more and more to be 

 something like an electromagnetic field filhng all space, 

 though having its greatest intensity in a small region. 

 Matter consisting of such elements is as remote from 

 daily life as any metaphysical theory. It differs from the 

 theories of metaphysicians only in the fact that its 

 practical efl&cacy proves that it contains some measure 

 of truth and induces business men to invest money on the 

 strength of it ; but, in spite of its connection with the money 

 market, it remains a metaphysical theory none the less. 



The second kind of sophistication to which the world 

 of common sense has been subjected is derived from the 

 psychologists and physiologists. The physiologists point 

 out that what we see depends upon the eye, that what we 

 hear depends upon the ear, and that all our senses are 

 liable to be affected by anything which affects the brain, 

 Hke alcohol or hasheesh. Psychologists point out how 

 much of what we think we see is supplied by association 



