REASON A FUNCTION OF MIND. 457 



are inseparably connected with the material substance of 

 our bodies. Just as the motive force of our flesh is involved 

 in the muscular form-element, so is the thinking force of 

 our spirit involved in the form-element of the brain. Our 

 spiritual forces are as much functions of this part of the 

 body, as every force is a function of a material body. We 

 know of no matter which does not possess force, and, con- 

 versely, of no forces that are not connected with matter. 

 When the forces manifest themselves in the phenomena of 

 motion, they are called active forces ; if, on the other hand, 

 the forces are in a state of rest, or of equilibrium, they are 

 called latent forces. 199 This is as true of inorganic natural 

 substances as of organic. The magnet attracting iron- 

 filings, powder exploding, steam driving the locomotive, are 

 active inorganic substances ; they work by active force just 

 as does the sensitive mimosa, when it folds its leaves at a 

 touch, as does the Amphioxus, when it buries itself in the 

 sand, as does man, when he thinks. Only in these latter 

 cases the combination of the different forces, appearing as 

 phenomena of motion, are much more complex and much 

 less easily recognized than in the former cases. 



Anthropogeny has led us to the conclusion that even in 

 the entire history of the evolution of man, in the history of 

 the germ, as well as in that of the tribe, no other active 

 forces have been at work, than in the rest of organic and 

 inorganic nature. All the forces at work there can be 

 reduced at last to growth to that fundamental function of 

 evolution by which the forms of inorganic, as well as of 

 organic bodies, originate. Growth, again, itself rests on the 

 attraction and repulsion of like and unlike particles. 194 It 

 has given rise to Man and to Ape, to Palm and Alga, to 



