OF THE SOCL. 



217 



union of simple into complex ideas was left very much in 

 the dark; as in chemistry, for a long time, chemical affinity 

 remained unexplained and obscure. Hume, in trying to 

 account for the conception of cause and effect, for the 

 inevitable connection which we recognise in the succes- 

 sion of phenomena, reduced this fundamental fact of all 

 experience to the custom or habit which the repetition 

 of the same sequence inevitably produces. Hartley, 

 adopting a similar explanation, confirmed and strengthened 

 it by supposing that this habit was acquired through the 

 physical constitution of the nervous system. He held 



p. IS). "For Herbart, as well as 

 for Locke and his successors, the 

 unity of the mind was primarily an 

 hypostasised abstraction of unity. 

 But the German thinker differs 

 from the English both in the manner 

 in which he arrived at this concep- 

 tion and in the psychological conse- 

 quences which he deduced from it. 

 It was through exclusive reliance 

 on the immediate evidence of in- 

 ternal perception that the country- 

 men of Bacon fell into this error. 

 With Herbart, on the contrary, it 

 was an integral part of an elaborate 

 and highlj' speculative system of 

 metaphysics. He was led by a pro- 

 cess of abstract reasoning to main- 

 tain the simplicity of the soul in 

 80 absolute a sense that he was 

 compelled to exclude from its in- 

 trinsic nature all variety and 

 difference whatever, including even 

 successive modification in time. 

 Thus he cannot, like Locke, treat 

 the mind as essentially a combining 

 agency, or, like Brown, as a sub- 

 stance passing through a series of 

 states. He is therefore unable to 

 introduce into his psychology the 

 metaphysical conception of the 

 unity of the soul, except by trans- 

 forming it, however inconsistently, 

 into a conception of synthetic unity, 



which takes a twofold form in its 

 application to presented content 

 and to mechanical interaction re- 

 spectively " (ibid., p. 19, et scq.) 

 Herbart, as we know, was influenced 

 by Leibniz. Now Leibniz in his 

 well-known criticism of Locke laid 

 stress on the fact that in mental 

 science we have not only to do with 

 what is in the intellect but also 

 with the intellect itself. This puts 

 the question of the combining agency 

 or unity of the soul into the fore- 

 ground. Herbart was further in- 

 fluenced by the mechanical sciences 

 of his age. But in dynamical 

 reasoning we deal with the com- 

 position of forces acting on a point 

 and merging into a resultant. And 

 it seems likely that putting these 

 two aspects together Herbart found 

 his way from the unity of the soul 

 to the multiplicity of psychical 

 phenomena under the conception 

 of the play of different forces, 

 whereas English psychologists, such 

 as Mill, fastened rather upon the 

 analogy of chemically different sub- 

 stances combining in the unity of 

 a compound with different proper- 

 ties. In fact, Herbart thought 

 mechanically, the Associatiouists, 

 chemically. 



