576 



PHILOSOPHICAL THOUGHT. 



25. 



Thomson 

 and Tait ; 

 Maxwell. 



ployed in scientific inquiry. A great revolution in 

 scientific thought followed the publication of Thomson 

 and Tait's ' Natural Philosophy ' and of Clerk Maxwell's 

 writings. We know that with these names is mainly 

 connected the introduction of the conception of energy 

 into all the better text-books of physical science. To 

 Thomson (Lord Kelvin) we owe two important steps in 

 the philosophy of nature as distinguished from natural 

 philosophy: first, the early recognition (1852) of that 

 universal property in natural phenomena in conse- 

 quence of which they exhibit, not only the conservation, 

 but also the dissipation or degradation ^ of energy, a 



which roughly covers the third 

 quarter of tiie century, Lotze was 

 the only thinker who in a consistent 

 and complete manner dealt with 

 the principles and conceptions 

 which underlie the natural sciences, 

 examining also critically to what 

 extent they could be utilised in 

 the formation of a comprehensive 

 creed. He did not, however, pub- 

 lish any concise exposition of his 

 views ; they aie scattered about his 

 systematic as well as his polemical 

 and more popular writings. At 

 regular intervals he delivered 

 courses of lectures on the subject, 

 beginning with the year 1846, 

 and ending in the year 1877 ; 

 the dictated lecture syllabus of 

 the last course was published 

 in 1882. The following extract 

 shows how Lotze, long before this 

 view was generally entertained, 

 had a perfectly up-to-date concep- 

 tion of the task of natural science 

 and of the purposes for which 

 scientific principles are defined and 

 employed by scientific thinkers : 

 "The natural sciences are, indeed, 

 not exclusively led by the demands 

 of practical life : thus they do not 

 aim wholly at the practical com- 



mand of the external world. They 

 are, indeed, contented with a cer- 

 tain theoretical command over the 

 same — i.e., they strive to deter- 

 mine from present facts their neces- 

 sary antecedents and to foretell the 

 necessarily following ones, also to 

 determine those to us unobservable 

 circumstances which coexist with 

 these which are accessible to our 

 observation. Tliey have gained this 

 object by analysing experience and 

 extracting general rules regarding 

 the connection of phenomena : 

 further, by framing hypotheses 

 regarding the actual facts which 

 underlie the changing phenomena, 

 and which make it possible through 

 the application of those general 

 laws to calculate from the given 

 parts of the course of things the 

 continuation of the same in con- 

 formity with actual existence." 

 Introduction to Syllabus on 

 'Naturphilosophie,' sect. 2. 



^ The term degradation imports 

 an attribute which is not purely 

 mechanical : it suggests that nat- 

 ural processes may belong to a 

 higher or lower grade. But for 

 the purely mechanical view the 

 difference is only that of more or 



