102 POPULAR SCIENCE MONTHLY. 



of modern times an invaluable protection and an uninterrupted 

 series of scientific gifts. The photometry of Lambert led not 

 only to the methods of modern technical photometry but also 

 to the measurement of our sensations of light, while the law of 

 relativity of sensations had been before Fechner established 

 for lights by Bouguer, Masson, Arago, Herschel, and Steinheil. 

 The study of the errors of observation in physics and astronomy 

 has led not only to the science of physical measurements, but also 

 to that of psychological measurements. Newton, Young, and 

 Maxwell began not only the science of ether vibrations, but also 

 the science of sensations of color. The laws of mechanics apply 

 not only to inanimate objects but also to the results of our own 

 volitions. In fact, in every department of psychology, progress 

 has been and still is closely dependent on the achievements of 

 physics and technology. 



Psychology has not only received most of its methods and 

 much of its material from physics ; it has for the first time in 

 history reached through physics a definite conception of its own 

 problem. The older psychology and philosophy had always main- 

 tained the necessity of directly investigating the facts of con- 

 sciousness. The standpoint was simple enough, but, as no scien- 

 tific methods of doing so were developed, the whole problem 

 remained vague and unsatisfactory. Among the proposals for a 

 better state of affairs was that of first investigating the nervous 

 system and then deducing psychological laws therefrom. The 

 brain was to be accurately mapped out into faculties, the paths of 

 nervous currents were to be traced along various fibers, and the 

 interaction of nervous molecules was to be known in every par- 

 ticular ; it was even expected that various cells could be cut out, 

 with a memory or a volition snugly inclosed in each. In other 

 words, there was to be no psychology except on the basis of a 

 fully developed brain physiology. Unfortunately, very little has 

 been ascertainable concerning the finer functions of the nervous 

 system. Aside from a general knowledge that the cerebellum 

 has to do with co-ordination of movements, the convolutions of 

 Broca have to do with speech, and similar facts, nothing of even 

 the remotest psychological bearings has been discovered concern- 

 ing the functions of the brain. The roseate hopes of those who 

 expected a new psychology out of a " physiology of mind " were 

 totally disappointed. In the effort for something new, however, 

 the psychologist supplied the data concerning the " molecular 

 movements" in the brain out of his own imagination ; the famil- 

 iar facts of mind were retold in a metaphorical language of " nerve 

 currents," " chemical transformation," etc., of which not one par- 

 ticle had a foundation in fact. The physiology of mind started 

 with an impossibility and ended with an absurdity. 



