RESULTS AND LIMITS OF SCIENTIFIC METHOD. 457 



were before almost impracticable. Since the time of 

 Newton and Leibnitz whole worlds of problems have 

 been solved which before were hardly conceived as matters 

 of inquiry. In our own day extended methods of mathe- 

 matical reasoning, such as the system of quaternions, 

 have been brought into existence. What intelligent man 

 wiR doubt that the recondite speculations of a Cayley 

 or a Sylvester may possibly lead to some new methods, 

 at the simplicity and power of which a future age will 

 wonder, and yet wonder more that to us they were so 

 dark and difficult. May we not repeat the words of Seneca : 

 * Veniet tempus, quo ista qua3 nunc latent, in lucem dies 

 extrahat, et longioris aevi diligentia : ad inquisitionem 

 tantorum aetas una non sufficit. Veniet tempus, quo pos- 

 teri nostri tarn aperta nos nescisse mirentur.' 



The Reign of Law in Mental and Social Phenomena. 



After we pass from the so-called physical sciences to 

 those which attempt to investigate mental and social 

 phenomena, the same general conclusions will hold true. 

 No one will be found to deny that there are certain uni- 

 formities of thinking and acting which can be detected 

 in reasoning beings, and so far as we detect such laws 

 we successfully apply scientific method. But those who 

 attempt thus to establish social or moral sciences, soon 

 become aware that they are dealing with subjects of 

 enormous perplexity. Take, for instance, the science of 

 Political Economy. If a science at all, it must be a mathe- 

 matical science, because it deals with quantities of com- 

 modities. But so soon as we attempt to draw out the 

 equations expressing the laws of variation of demand and 

 supply, we discover that they must have a complexity 

 entirely surpassing OUT powers of mathematical treatment. 



