450 SCIENCE PROGRESS 



light of science at last reaches them, and some tentacle pushed 

 forth at hazard suddenly lights up the scene which had been 

 wrapped in impenetrable gloom. Until that occurs — and with 

 many problems it may never occur — we must be content to 

 leave these questions in the region of the Unknown, while yet 

 chary of asserting that they are unknowable. To say that a 

 thing is intrinsically unknowable already implies some know- 

 ledge of it. It implies that science has already advanced so 

 far as to see that the chasm between it and us is impassable, 

 and it often happens that we are unable consistently to affirm 

 even that modicum of knowledge on the subject. At all events, 

 we shall in the course of these papers on the progress of philo- 

 sophy take our stand on the proposition that through the 

 medium of natural science alone can the solutions of philo- 

 sophical problems be discovered. When any such problem is 

 presented to us, our first concern therefore must be to ascertain 

 to what branches of science it may be amenable ; and if we find 

 it amenable to none, then we have no resource but to leave it 

 in the darkness, hoping that at some future time the dawn may 

 illumine that, as it has so many other of the paradoxes of 

 philosophy. 



From this point of view, let us approach the problem of the 

 relation of mind and matter, on which various works have lately 

 been published. The point of view of animals and of young 

 children is purely objective ; their regards are turned outwards 

 rather than inwards ; it would be true to say of them that their 

 knowledge is of matter only, and not of mind. Later in evolu- 

 tion comes the consciousness of internal sensations, as apart 

 from objective matter. At length the philosopher Berkeley 

 pointed out that it is only through the medium of the senses 

 that external objects are known at all. We are not directly 

 aware of the object, but of a sensation only, which we interpret 

 to be an external object. Hence the world consists of sensations 

 and feelings alone ; what else there may be is a matter of 

 inference, and not of immediate experience. Thus originated 

 the theory of idealism, which received a far more perfect ex- 

 pression in the hands of Hume. 



The new theory quickly fell under the scourge of the disciples 

 of common-sense. Dr. Johnson thought to refute it by kicking 

 a stone, as though anyone had denied that this exercise would 

 produce a sensation of hardness and external reality. More 



