22 POPULAR SCIENCE MONTHLY. 



Benno Erdmann, of Bonn, a man profoundly learned in historical 

 philosophy, who has advanced by important contributions, not unre- 

 lated, two such different sciences as experimental psychology and mod- 

 ern logic, in which he is an acknowledged master. 



This session promised well from the start. The audience was 

 representative in more ways than one. In addition to the professional 

 philosophers, a number of remarkable men of science were present. 

 In the front row, for instance, sat Svante Arrhenius, of Stockholm, 

 physical chemist, famous for his mathematical and experimental contri- 

 butions to the theory of solutions and speaker for cosmieal physics, 

 and Ludwig Boltzmann, of Vienna, mathematical physicist, distin- 

 guished especially for his work in the kinetic theory of gases, who 

 represented applied mathematics in the program of the congress. 

 Scattered through the audience were many eminent leading repre- 

 sentatives of both the physical and mental sciences. Among Americans 

 on the front were Loeb in biology and Cattell in psychology, both 

 eminent specialists actively interested in scientific methods, both 

 having applied exact methods with conspicuous success, albeit in very 

 different ways, to the investigation of phenomena of life and mind. 

 This is not the place to attempt a summary of the leading addresses, 

 both delivered in German. Suffice it to point out that Ostwald pre- 

 sented a classification of the sciences professedly based on the empirical 

 standpoint of energetics, and bearing but slight resemblance to the 

 elaborate scheme which shaped the program of the congress. Erdmann 

 attacked the subject from a frankly a priori point of view, arguing for 

 the position which has recourse to a generating principle of logical 

 necessity. Among those who took part in the open discussion were 

 Boltzmann, Hoeffding, Ormond, Miss Calkins, etc., and the chief 

 speakers again in reply. 



In the section for ethics the speakers were Professor William B. 

 Sorley, of Cambridge, able philosophical moralist, keen critic of the 

 ethics of naturalism, who has made sound learning, astuteness and 

 vigor of mind tell also in the study of the more vital questions of 

 practice, and Professor Paul Hensel, of the University of Erlangen, 

 philosophical scholar and critic, a gifted student of ethical theory and 

 interpreter of ethical ideals in literature. The first address in the 

 esthetics section was made by Dr. Henry Eutgers Marshall, of New 

 York, a successful architect by profession, a philosopher by instinct 

 and performance, distinguished as a philosophical student of psychol- 

 ogy and a psychological student of esthetics, who has made interesting 

 contributions to the analytical and genetic aspects of both sciences. 

 The second speaker was Professor Max Dessoir, of the University of 

 Berlin, erudite historian of German psychology in all its ramifications, 

 himself a philosopher, psychologist and esthetician. 



And so one might run through the long program, apart from a 

 fortunate limitation of space and an unfortunate but inevitable igno- 



