iJ U XI 1^ i u irj. 



the word "energy" (as an equivalent to "work" in the 

 physical sense) is still used in many different senses, as 

 is also the word ' ' force. ' ' Others define energy as ' ' work 

 or all that comes of work and may be converted into 

 work." One particular school of voluntarism (Wundt) 

 reduces the motive-force of energy to will. Crusius said 

 in 1744: "Will is the dominating force in the world." 

 And Schopenhauer defines the world (or substance) as 

 "will and presentation." 



' C. Sensation. — In describing sensation (in the broad- 

 est sense) as a third attribute of substance, and sepa- 

 rating "sensitive substance" from energy as "moving 

 substance," I rely on the observations I made in the thir- 

 teenth chapter of the Riddle on sensation in the organic 

 and inorganic world. I cannot imagine the simplest 

 chemical and physical process without attributing the 

 movements of the material particles to unconscious sen- 

 sation. In this sense the chemist speaks every day of 

 a sensitive reaction, and the photographer of a sensitive 

 plate. The idea of chemical affinity consists in the fact 

 that the various chemical elements perceive the quali- 

 tative differences in other elements, experience "pleas- 

 ure" or "revulsion" at contact with them, and execute 

 their specific movements on this ground. The sensitive- 

 ness of the plasm to all kinds of stimuli, which is called 

 "soul" in the higher animals, is only a superior degree 

 of the general irritability of substance. Empedocles 

 and the panpsychists spoke in the same sense of sensa- 

 tion and effort in all things. As Nageli said: "If the 

 molecules possess something that is related, however 

 distantly, to sensation, it must be comfortable to be able 

 to follow their attractions and repulsions ; uncomfortable 

 when they are forced to do otherwise. Thus we get a 

 common spiritual bond in all material phenomena. The 

 mind of man is only the highest development of the 

 spiritual processes that animate the whole of nature." 

 29 449 



