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that of Jastrow, because the nielliod of Fouoautt is certainly in- 

 correct (as has been demonstrated among otliers by G. E. Muller), 

 whilst that of Jastrow is not quite free of arbitrariness. 



Against all these different ways of using the method of the false 

 and true cases, I must raise a fundamental objection, which I will 

 try to elucidate here. 



Whenever two stimuli of different physical intensity are brought 

 to act on one of the organs of the senses, either the reagent will 

 be able to give some information as to the difference between these 

 stimuli, or he will not be able to do so. If he cannot give any 

 information, then we have before us a dubious case, if on the con- 

 trary Jie is able to give some information, this information may 

 either be correct, — this constituting a true case — or it may be 

 incorrect, when we shall have a false case. 



If the experiment is repeated a sufficient number of times, we 

 shall have obtained at last a certain number of true cases iv, of 

 false cases v and of dubious cases t. 



Generally it is admitted that the reagent has indeed perceived 

 correctly iv times, that he has been mistaken v times, that he 

 was in doubt t times. If this premiss were correct, Fechner's or 

 G. E. Müller's views might be correct too. This however is not the 

 case. An error has already slipped into the premiss, as will become 

 evident furtheron. 



No difference of opinion exists as to the dubious cases. To 

 this category belong first those cases, where the reagent got the 

 impression of positive equality, and next those cases, where he 

 did not perceive any difference, and consequently was in doubt. 

 Together they embrace such cases only, in which a greater or lesser 

 or even infinitesimal physical difference was not perceived. 



Neither need any difference of opinion exist as regards the false 

 cases. In these cases a stimulus has been acting on the organs of 

 the senses, and information was given about the effect, but on account 

 of a series of circumstances, independent of the will of the reagent, 

 his judgment was not in accordance with the physical cause. The 

 physical cause therefore has not been perceived, but accidental cir- 

 cumstances led the reagent to believe that he was able to emit a 

 judgment, though this judgment, accidentally, was an incorrect one. 



And now we are approaching the gist of the argument. If it be 

 possible, that amongst a series of experiments a certain number 

 occur, in which the reagent really does not perceive the physical 

 cause, but is yet induced by chance to emit a judgment which proves 

 to be an incorrect one, then there ought to be also a number of 



