Mechanistic Biology 255 



which is studied by the psychologist. It is important to distinguish 

 this view from the psychophysical theory described by McDougall 

 as Phenomenalistic parallelism, and originally put forward by 

 Spinoza and Kant. According to their opinions, there was no 

 causal connection between mind and body, but both were the shadow 

 thrown by some underlying reality, just as two shadows are often 

 seen thrown by the same object when two light' exist on the other 

 side of it. This may be represented by the folio .vinj^ diagram : 



Mental processes. 



The underlying processes. 



Bodily processes. 



Against this there are rather unanswerable arguments to be 

 adduced, and I should prefer to confine the two-aspect view to the 

 metaphysical field and allow that psychophysical interaction does 

 go on. In other words, it is not so much body and mind that are 

 two aspects of one underlying reality, but matter and spirit. This 

 view can be represented by the following scheme : 



Mental processes. 



'(s) 



'<b 



-► The underlying processes. 



® 



Bodily processes. 



The philosophy of Theodore Merz is most helpful in the dis- 

 cussion of this question. The quotations are taken for convenience 

 from Jevons' appreciation of him. Merz considered that the 

 history of British philosophy during the seventeenth and eighteenth 

 centuries was one of the most important phases of human thought. 

 " Berkeley finally dropped the idea of matter as unnecessary, 

 Hume showed that there was no foundation for the idea of a 

 spiritual or thinking substance." The classical school of Philosophy 

 thus evacuated itself and scepticism supervened, at first unrecognised 

 but eventually thoroughly conscious. 



Merz attempted to continue the classical tradition, and felt 

 that it led not to emptiness but to a very real constructive result. 

 He accepted all thfe reasoning of Berkeley and Hume, only he broke 



