GROWTH AND DIFFUSION OF CRITICAL SPIRIT. 181 



last, in these two very different regions, a firm 

 foundation and universal principles had been discovered 

 which would work in with the general tendency of 

 philosophical thought as it was announced in the 

 critical works of Kant, temporarily pushed aside l)y 

 the idealistic movement and recently revived by the 

 proclamation of the necessity of a return to Kant. It 

 was then remembered that Kant himself had made the 

 existence of geometrical and dynamical knowledge a 

 starting-point in his critical attempt to refute the 

 scepticism of Hume, and it was only natural that this 

 appeal to the certainty of mathematical knowledge 

 should be repeated and urged afresh in the light of 

 the mathematical investigations which led Eiemann, 

 and the physiological which led Helmholtz, to the 

 critical study of our space-conceptions. On the other 

 side, it was also remembered how Kant was one of the 

 first to study the mechanism of the universe from a 

 genetic point of view, and that in one of his three 

 * Critiques ' he put into the foreground the study of 

 teleology — i.e., of final causes and of purpose in the 

 living creation, a feature the mechanical explanation of 

 which was suggested in the ' Origin of Species.' 



It is not necessary at present to do more than merely 

 refer to the enormous literature and the endless dis- 

 cussions which during the last third of the century 

 circle round the problem of the foundations of mathe- 

 matical knowledge on the one side and of the principle 

 of organic evolution on the other. It is sufficient at 

 present to note how criticism in all its branches has 

 been influenced by one or the other of these lines of 



