88 Herbert Spencer's Synthetic Philosophy. 



eensorial and therefore wholly natural data, then all meta- 

 physical conceptions out of which philosophy had been 

 hitherto constructed could be nothing but idle illusions, and 

 all existing metaphysics nothing but a baseless dream, a mere 

 castle in the air. 



Kant's life-long and most earnest endeavor was to extricate 

 philosophy from these God and soul eliminating implications 

 of sensorial experientialism. With him the problem assumed 

 the following form : Is our mind endowed or not endowed 

 with a faculty of forming a priori synthetical propositions? 

 Or, in other words, is it or is it not capable of forming 

 knowledge of some kind without the existence of sensorial 

 experience ? If not, then the cause of metaphysical philoso- 

 phy is hopeless. 



Kant believed that in pure mathematics he had discovered 

 a kind of knowledge constructed wholly from a priori data 

 by the mind without the aid of sensorial experience. That 

 the truths of pure mathematics consist of such a priori syn- 

 thetical propositions is the fundamental assertion upon 

 which the entire Kantian philosophy is grounded. To make 

 good his case, he had first to show that space and time, in 

 which all mathematical constructions take form, are them- 

 selves a priori possessions of the mind, and he had further- 

 more to show that the synthetic power the power which 

 combines particular data into systematic knowledge is like- 

 wise an a priori possession of the mind. 



Philosophers in Germany before Kant had looked upon 

 perception, or the manifold of experience which appears in 

 time and space, as merely an indistinct kind of apprehen- 

 sion, whose clear and distinct knowledge they held to con- 

 sist exclusively in concepts. Kant now declared perceptual 

 sensibility to be a fundamental faculty of the mind alto- 

 gether distinct from its conceptual apprehension. > Accord- 

 ing to him, this original or pure perceptual sensibility of the 

 mind consists in the empty forms of space and time, which 

 he calls the outer and the inner sense, respectively. Into 

 these a priori forms of our sensibility all sense-derived ma- 

 terial, all a posteriori or externally imparted sensorial data, 

 are received. This occurs in a purely receptive manner 

 without the active part of our nature coming into play. 

 The active part of our nature Kant declares to be intelligence 

 exclusively. In his view sensibility is an entirely passive 

 faculty, all activity being exclusively a matter of intellect. 



It is this lodging of all activity, of all combining and ap- 



