330 'Journal of Comparative Neurology and Psychology. 



vestigators to whom it is more important that scieiitilic propositions 

 shall be verifiable than that thej shall be anscliaulicli. Let us here 

 look in a general way at the contrast between the results reached by 

 making ''Anschanliehkeit" the ideal, and those which flow from 

 making verifiablcness the ideal. 



For many investigators the object of science is to prepare a system 

 of verifiable propositions, in order that we may know what to depend 

 on in our conduct ; ''to know what is true in order to do what is 

 right," as Huxley put it. Verifialjle projjositions are propositions 

 that say "Under such and such conditions you will find such and 

 such things to occur or exist."' Now, if one supj)lies the conditions 

 set forth, and does nut find the })rcdicted things to occur or exist, the 

 ])roposition is not verifiable, and many would therefore hold that it 

 should be stricken from science. A large proportion of the propo- 

 sitions concerning machinedike structures in organisms, given by v. 

 IJexkiill, do not even profess to l)c verifiable. One of the main 

 objects of investigation is to find out what particular kinds of 

 machines are i)resent in aninuils, and how these actually present 

 machines have arisen and lioW they are changing. This object is 

 incompatible with the mere assumption of fictitious machines, for 

 the first result of investigation with this object in ^'iew is to cancel 

 these fictitious machines. This would indeed leave our science for 

 a time less shar})ly formulated, but "at a certain stage in the develop- 

 ment of a science a degree of vagueness is what best consists with 

 fertility,"^ for reference of the phenon^ena to complete fictitious 

 machines tends to cut oft" search for the real ones. When we have 

 found out what really occurs in organisms and what machines 

 actually exist there, then our knowledge will be as "anschaulich" 

 as the facts warrant, no more, no less. 



To the present reviewer it seems that, even for practical purposes, 

 the author has overestimated the value of a rather gross "Anschau- 

 lichkeit." . The bringing in of machine-like strncturcs, — tubes, 

 valves, etc., — that confessedly do not exist, seems rather to confuse 



"Or, ])ut in a form which holds wliatovcr one's theories, "when yon liave 

 such and such experiences, you will ha\e such and such other experiences." 

 'Vrm. James, Psychology, I'reface. 



