106 



PHILOSOPHICAL THOUGHT. 



12. science, how is it that science has escaped the ravages 



How has 



science of the critical spirit ? The answer to this question will 



escaped ? 



introduce us to another large department of the philo- 

 sophical thought of the nineteenth century that which 

 deals with the foundations, the validity, and the value 

 of scientific thought and knowledge. Ever since Kant 

 wrote his ' Critique of Pure Eeason ' the questions re- 

 garding the principles of science and the nature of 

 mathematical reasoning have formed a very important 

 chapter of philosophy. The subject has been approached 

 from the side of logic, psychology, metaphysics, and 

 science itself ; both philosophical and scientific authorities 

 have contributed towards the solution of the problem ; 

 perhaps it may be said that it marks one of the few 

 provinces of philosophical thought in which we seem 

 to be approaching a consensus of opinion, to be 

 attaining to a tolerable agreement between philo- 

 sophical and scientific thinkers. There are few other 

 instances in the large region of philosophical thought 

 where as much as this could be said. These questions 

 centre in the changed view which we take of nature and 

 natural knowledge, the altered meanings which we attach 

 to these words. In the sequel I shall devote a special 

 chapter to this subject, 

 is. In the meantime it is sufficient to say that science, 



The escape . . 



has not been scientific knowledge, and scientific theories have not 



complete. 



escaped the attacks of the critical spirit. 1 The main 



1 1 do not here refer to the never- 

 ending cavillings, on the part of 

 theologians, against the results and 

 teachings of scientific thinkers. I 

 refer to investigations into the 

 principles of scientific reasoning 



and the nature of scientific evi- 

 dence, be it that of the senses 

 or of the logical processes. In 

 modern times these investigations 

 start with Locke, and were con- 

 tinued in his spirit by Mill ; more 



