THE PRINCIPLES OP SCIENCE. 



ABC aBC 



Abe abC. 



The difficulty becomes much greater when more terms 

 enter into the combinations. It would require some little 

 examination to ascertain the complete conditions fulfilled 

 in the combinations 



ACe abCe 



BO abcE. 



aBcdE 



The reader may discover easily enough that the principal 

 laws are C = e, and A = Ae ; but he would hardly discover 

 without some trouble the remaining law, namely, that 

 BD = BDe. 



The difficulties encountered in the inductive investigations 

 of nature, are of an exactly similar kind. We seldom 

 observe any law in uninterrupted and undisguised opera- 

 tion. The acuteness of Aristotle and the ancient Greeks 

 did not enable them to detect that all terrestrial bodies 

 tend to fall towards the centre of the earth. A few nights 

 of observation might have convinced an astronomer 

 viewing the solar system from its centre, that the planets 

 travelled round the sun ; but the fact that our place of 

 observation is one of the travelling planets, so complicates 

 the apparent motions of the other bodies, that it required 

 all the sagacity of Copernicus to prove the real simplicity 

 of the planetary system. It is the same throughout 

 nature; the laws may be simple, but their combined 

 effects are not simple, and we have no clue to guide us 

 through their intricacies. " It is the glory of God," said 

 Solomon, " to conceal a thing, but the glory of a king to 

 search it out." The laws of nature are the invaluable 

 secrets which God has hidden, and it is the kingly pre- 

 rogative of the philosopher to search them out by industry 

 and sagacity. 



Inductive Problems for Solution ly the Reader. 



In the first edition (vol. ii. p. 370) I gave a logical 

 problem involving six terms, and requested readers to 

 discover the laws governing the combinations given. I 

 received satisfactory replies from readers both in the 

 United States and in Eifgland. I formed the combina- 



