534 SCIENCE PROGRESS 



has lately been pointed out that Descartes three hundred years 

 ago did sketch out a theory having some sort of crude resem- 

 blance to the theory of Einstein. The contention is true, and 

 it is far more than mere chance. Descartes possessed an 

 intellectual power which does not arise more than once in 

 several generations ; his penetration into natural phenomena 

 may almost be described as superhuman. But the contention 

 nevertheless does not bear out the conclusions for which it 

 was brought — namely, to justify the methods of metaphysics. 

 For Descartes' mind embraced, not merely all the metaphysics 

 of his time, but all the science of his time as well, in so far 

 as Science was differentiated from Philosophy. He was a 

 distinguished mathematician ; he was also a distinguished 

 physiologist, and very clearly set forth the doctrine of physio- 

 logical automatism which only came into general recognition 

 in the nineteenth century. So far from the prevision of 

 Descartes furnishing an argument for the validity of meta- 

 physical methods, it presents an additional proof of their 

 invalidity. For three hundred years, metaphysicians have 

 had before them Descartes' adumbration of a true theory ; 

 for three hundred years they have operated upon it by meta- 

 physical methods ; and in all that time have not succeeded in 

 advancing it one whit. Even with a rough approximation to 

 truth before them, they can make nothing of it. But as 

 soon as the man of science comes in with experimental methods, 

 truth begins to appear, even to those who had not the previous 

 advantage of studying the first approximation. Ten years of 

 physics have given results which could not have been reached 

 at the previous rate of progress in a thousand years of meta- 

 physics. 



A philosophic reviewer is not called upon for an opinion 

 as to whether Einstein's theory is true, or whether parts of 

 it are true, or adumbrations of the truth. He has only to note 

 its philosophical bearings. Principal among these is that it 

 does remove theories of space and time from the ambiguous 

 and temporary position which they occupied as a branch of 

 metaphysics. They are brought definitely into science, and 

 linked up with the rest of our knowledge about the universe. 

 And the same is true of Gravitation, which has hitherto occu- 

 pied an anomalous and isolated position. All these are brought 

 by Einstein into the sphere of science. 



It has, however, been objected to on the ground that it 

 is itself metaphysical in tendency ; and that by certain meta- 

 physicians it has been received with obvious acclamation. But 

 too much importance need not be attached to this latter point. 

 Metaphysicians generally tend to favour any theory in pro- 

 portion to its obscurity ; and the principle of Relativity presents 



