234 THE DIRECTION OF MOTION. 



we conceive them to possess are nothing else than these per- 

 ceptible properties idealized. Centres of force attracting 

 and repelling each other in all directions, are simply insensi- 

 ble portions of matter having the endowments common to 

 sensible portions of matter endowments of which we can- 

 not by any mental effort divest them. In brief, they are 

 the invariable elements of the conception of matter, abstract- 

 ed from its variable elements size, form, quality, &c. And 

 so to interpret manifestations of force which cannot be tac- 

 tually experienced, we use the terms of thought supplied 

 by our tactual experiences : and this for the sufficient reason 

 that we must use these or none. 



After all that has been before shown, and after the hint 

 given above, it needs scarcely be said that these universally 

 co-existent forces of attraction and repulsion, must not be 

 taken as realities, but as our symbols of the reality. They 

 are the forms under which the workings of the Unknowable 

 are cognizable by us modes of the Unconditioned as pre- 

 sented under the conditions of our consciousness. But while 

 knowing that the ideas thus generated in us are not absolute- 

 ly true > we may unreservedly surrender ourselves to them as 

 relatively true ; and may proceed to evolve a series of deduc- 

 tions having a like relative truth. 



75. From universally co-existent forces of attraction 

 and repulsion, there result certain laws of direction of all 

 movement. Where attractive forces alone are concerned, or 

 rather are alone appreciable, movement takes place in the 

 direction of their resultant; which may, in a sense, be 

 called the line of greatest traction. Where repulsive forces 

 alone are concerned, or rather are alone appreciable, move- 

 ment takes place along their resultant; which is usually 

 known as the line of least resistance. And where both at- 

 tractive and repulsive forces are concerned, or are apprecia- 

 ble, movement takes place along the resultant of all the 

 tractions and resistances. Strictly speaking, this last is the 



