TEE EVOLUTION TEEORY. 



293 



Finally, this view rests upon the study of In- 

 fusoria, Amoebae, and other one-celled organisms. 

 In them we again find, in the individual, isolated 

 cells, the same manifestations of psychic life, sen- 

 sation and perception, will and movement, as in 

 the higher animals, which consist of multitudi- 

 nous cells. In sociate as well as in solitary cells 

 the psychical life resides in one and the same 

 substance — protoplasm. Further, we know that 

 moneres and other rudimentary organisms — mere 

 detached bits of protoplasm — possess sensation 

 and the power of movement, just as does the en- 

 tire cell. From this we should conclude that the 

 cell-soul, which is the basis of scientific psycholo- 

 gy, is itself only a compound, i. e., the sum of 

 the psychic properties of the protoplasmic mole- 

 cules, called also plastidules. 1 Thus the soul of 

 the plastidule would be the ultimate factor to 

 which could be reduced the psychic life of living 

 things. 



Does the doctrine of evolution hereby ex- 

 haust its psychological analysis ? By no means. 

 The new organic chemistry teaches us that it is 

 the physical and chemical properties of a certain 

 element, carbon, which, by its complex combina- 

 tions with other elements, produces the special 

 psychological properties of organized bodies, and 

 in particular of protoplasm. The moneres, con- 

 sisting only of protoplasm, form as it were a 

 bridge over the deep gulf which divides organic 

 from inorganic Nature. They show us how the 

 simplest organisms must have sprung, in the be- 

 ginning, from inorganic carbon combinations. If 

 a certain number of carbon-atoms combined with 

 a certain number of hydrogen, oxygen, nitrogen, 

 and sulphur atoms to form a unit, a plastidule, 

 we may regard the soul of the plastidule, that is 

 to say, the sum total of its vital properties, as the 

 necessary product of the forces of all the atoms 

 combined. Then, from the monistic point of 

 view, we may call this sum of the atomic forces 

 the soul of the atom. From the chance meeting 

 and the multiplied combinations of these atom- 

 souls — always constant, always incommutable — 

 come the multiple and highly-variable souls of 

 the plastidules, which are the molecular factors 

 of organic life. 



Having reached these extreme psychological 

 consequences of the monistic doctrine, or of the 

 doctrine of evolution, we meet again those an- 

 cient ' conceptions of the universal animation of 



1 Plastidules, protoplasm molecules considered as 

 the elementary factors of all vital properties. They 

 are. so to speak, organic atoms, the atoms of the pby- 

 iioloeist. 



matter, which have been variously expressed by 

 such philosophers as Democritus, Spinoza, Bru- 

 no, Leibnitz, and Schopenhauer. All psychic life 

 is ultimately reducible to two elementary functions, 

 namely, sensation and motion : on the one hand, 

 excitation ; on the other, reflex movements. The 

 simple sensation of pleasure or displeasure, the 

 simple motion of attraction or of repulsion, are 

 the sole elements which, by an endless series of 

 complex combinations, constitute the whole sum 

 of psychic activity. The hate or the love of 

 atoms, the attraction or the repulsion of mole- 

 cules, the motion and sensation of cells and cel- 

 lular organisms, the thought and consciousness 

 of man, these are the different steps of one and 

 the same evolutive psychological process. 



The unitary conception of the universe, or 

 monism, toward which the new doctrine of evolu- 

 tion leads us, puts an end to the opposition which 

 has hitherto existed between the various dualistie 

 systems of the universe. It avoids the narrow- 

 ness of both materialism and spiritualism ; it com- 

 bines practical idealism with theoretical realism ; 

 it unites the science of Nature and the science of 

 mind in one unitary general science, which com- 

 prises all. 



The present theory of evolution is not only of 

 very great theoretical value, as forming the con- 

 necting link between these different sciences ; it 

 furthermore yields practical results. Neither medi- 

 cine, considered as an applied natural science, nor 

 political economy, jurisprudence, or theology, in 

 so far as they form a part of applied philosophy, 

 can henceforth resist its influence. Nay, I am 

 convinced that it is precisely in such domains 

 that it will prove to be the most powerful lever 

 of progress and perfectionment ; and, inasmuch 

 as the great aim of the sciences just named is the 

 education of the young, the doctrine of evolution, 

 as being the most potent instrument of education, 

 must make its authoritative voice heard even in 

 the school-room. It must not enter the school 

 simply by tolerance, but must be its directing 

 principle. 



If I may be permitted briefly to call attention 

 to the more important aspects of this question, I 

 would first of all dwell upon the paramount advan- 

 tages of the genetic method. Both teachers and 

 pupils will take infinitely greater interest in the 

 subject-matter of instruction, if, first of all, they 

 put to themselves the question, " How did this 

 thing come into existence — how did it develop ? " 

 With the question of development comes that of 

 causality, and after all it is the knowledge that 

 we acquire of proximate causes, and not the 



