338 THE PRINCIPLES OF SCIENCE. 



nation of the strata of the globe becomes more and more 

 complete, our views of the origin and succession of life 

 upon the globe must undergo many changes and ex- 

 tensions. 



Unclassed Exceptions. 



At every period of scientific progress there will neces- 

 sarily exist a multitude of exceptional and unexplained 

 phenomena which we know not how to regard. They are 

 the outstanding facts upon which the labours of investi- 

 gators must be exerted, the ore from which the gold of 

 future discovery is to be extracted. It might be thought 

 that, as our knowledge of the laws of nature increases, 

 the number of such exceptions should decrease ; but, on 

 the contrary, the more we know the more there is yet to 

 learn and explain. This arises from several reasons ; in 

 the first place the principal laws and forces in nature are 

 numerous, so that he who bears in mind the wonderfully 

 large numbers developed in the doctrine of combinations, 

 will anticipate the existence of almost infinitely nume- 

 rous relations of one law to another. When we are once 

 in possession of a law, we are potentially in possession of 

 all its consequences ; but it does not follow that the mind 

 of man, so limited in its powers and capacities, can actu- 

 ally work them all out in detail. Just as the aberration 

 of light was discovered empirically, though it should have 

 been foreseen, so there are doubtless multitudes of unex- 

 plained facts, the connexion of which with laws of nature 

 already known to us, we should perceive, were we not 

 hindered by the imperfection of our deductive powers. 

 But, in the second place, as will be more fully pointed 

 out, it is not to be supposed that we have in any degree 

 approximated to an exhaustion of nature's powers. The 



