176 DESCARTES' DISCOURSE ON METHOD iv 



feel more, or less, than a knowledge of states of 

 consciousness. And our whole life is made up of 

 such states. Some of these states we refer to a 

 cause we call "self;" others to a cause or causes 

 which may be comprehended under the title of 

 " not-self." But neither of the existence of " self," 

 nor of that of " not-self," have we, or can we by 

 any possibility have, any such unquestionable 

 and immediate certainty as we have of the 

 states of consciousness which we consider to 

 be their effects. They are not immediately ob- 

 served facts, but results of the application of the 

 law of causation to those facts. Strictly speak- 

 ing, the existence of a " self" and of a " not-self" 

 are hypotheses by which we account for the 

 facts of consciousness. They stand upon the same 

 footing as the belief in the general trustworthiness 

 of memory, and in the general constancy of the 

 order of Nature as hypothetical assumptions 

 which cannot be proved, or known with that 

 highest degree of certainty which is given by im- 

 mediate consciousness ; but which, nevertheless, 

 are of the highest practical value, inasmuch as the 

 conclusions logically drawn from them are always 

 verified by experience. 



This, in my judgment, is the ultimate issue of 

 Descartes' argument; but it is proper for me to 

 point out that we have left Descartes himself some 

 way behind us. He stopped at the famous 

 formula, " I think, therefore I am." Yet a little 



