PHILOSOPHY OF NATURE LEIBNITZ'S IDEAS. 37 



relation established beforehand in every substance in the 

 universe which creates its general communion, and creates 

 particularly the union between soul and body. We may 

 hence understand how the soul has its seat in the body 

 by near and direct presence, for it is in it as unity is in 

 multitude. The soul, a thinking monad, acts in conso- 

 nance with inferior but still vital monads, which, concur- 

 rently with it, are manifested by the organized substance in 

 which thought has its seat. The soul is in relations with 

 the lower activities of life, as they are with the still duller 

 activities of mere matter, in a companionship which is not 

 a dependence. 



We must now rise higher, and study the relations and 

 the communion between monads in the universe. Three 

 principles, that of preestablished harmony, that of con~ 

 tinuity, and that of the sufficient reason, are here the basis 

 of Leibnitz's philosophy. Preestablished harmony ex- 

 presses nothing else than the combination of all monads in 

 the universe. Our mind perceives an infinity of relations 

 among them, of which it does not grasp the physical ne- 

 cessity. It does not know why two monads act in concert, 

 or the one upon the other, to bring about some special 

 results. It cannot explain how monads of a lower order 

 exert influence over those of a higher order, those of the 

 body on those of the soul, and reciprocally. In a word, as 

 Hume demonstrates, we perceive no logical and necessary 

 connection between phenomena which follow each other in 

 the successive relations of cause and effect. Yet we are 

 certain that no single molecule in the world is alien to the 

 rest, that not one is isolated from the whole, that all are 

 conjoint and act together in the whirl of general existence. 

 We remark that every effect depends on an infinity of 

 causes, and that every cause has an infinity of effects. The 

 concourse, the common action, the consensus of all these 

 monads toward a regular order, manifestly prove an estab- 



