THE NATURE OF STIMULATION 27 



explosive combination in consequence of former processes 

 assumed quite a peculiar labile position, had not in the evolution 

 of the muscle in the growth and metabolism certain combinations 

 been formed, and certain chemical processes taken place. 



Therefore if I do not analyze these previously existing pro- 

 cesses and the conditions brought about by them in the system 

 of the explosive substances or the muscle, and simply know the 

 condition added last, then I have learned nothing of the process 

 itself, have explained nothing. The time of application of a new 

 condition does not justify in any degree the assignment of a domi- 

 nant position to a factor. But more : in many cases there is not 

 a question at all of the addition of a process to an existing state, 

 but rather of the simultaneous interference of two or more pro- 

 cesses. Several conditions can appear at the same time. In other 

 cases the sequence of the combination can be reversed. Which 

 then is the cause? Has the process several causes, or has it no 

 cause? Here one sees plainly to what absurd results it leads if 

 time alone is used as a basis of the conception of cause. To 

 illustrate this I return to the case of the liberation of carbon 

 dioxide from carbonate of sodium. I place anhydrous carbonate 

 of sodium in a beaker and add hydrochloric acid. The carbon 

 dioxide escapes. Here the addition of hydrochloric acid would 

 be assumed to be the cause of the freeing of the gas. Then I put 

 hydrochloric acid in a beaker and add carbonate of sodium. The 

 same process takes place, but now the addition of carbonate of 

 sodium would be considered the cause for the formation of gas. 

 Now I put both simultaneously into a beaker. Again the same 

 process. Which was now the cause? Has the process now two 

 or has it no cause at all? Finally I put anhydrous carbonate of 

 sodium and hydrochloric acid in ether solution into the beaker. 

 The formation of gas does not take place, and yet both causes for 

 this formation of gas are present, the carbonate of sodium and the 

 hydrochloric acid. Only when I add water to the mixture does the 

 formation of carbon dioxide take place. Here water would be 

 considered the cause. Hence every condition would be in suc- 

 cession the cause for one and the same process. Under some 

 circumstances the same process would have several and in others 



