WHAT METAPHYSICS MEAN. I7I 



US conscious of the errors of the bad metaphysics of 

 common life and common science, and to avoid 

 such views of fundamental principles as will make 

 nonsense of all things. In this respect metaphysics 

 resemble logic, the science of the principles on 

 which our thought proceeds ; for logical principles 

 also cannot be with impunity ignored. If we are 

 ignorant of them, it is probable that our thought 

 will misapply them ; but to dispense with them is 

 impossible. But though metaphysical and logical 

 principles cannot be dispensed with, it is not neces- 

 sary to be conscious of them ; on the contrary, just 

 as people reasoned rightly and thought logically 

 long before Aristotle explicitly stated the principles 

 of logic, so it is possible to discover and to use 

 metaphysical principles in ordinary life and in . 

 science long before they are consciously appro- 

 priated by systematic philosophy. 



And so it is not too much to say that every con- 

 siderable advance in science has involved a parallel 

 advance in our view of metaphysical first principles ; 

 and it would not be difficult to illustrate this by 

 the history of metaphysical principles of acknow- 

 ledged importance, which have owed their dis- 

 covery, or at least their acceptance, to the progress 

 of the other sciences. Thus it was nothing but 

 Newton's discovery of gravitation which enabled 

 the principle of Interaction to supersede the old 

 conceptions of Activity and Passivity {cf, ch. iii. 

 § 10) ; and the full import of the metaphysical re- 

 volution which was thus worked by a physical 

 discovery has hardly even now been realized in all 

 philosophic controversies (ch. xii. § lo).^ 



^ It must not, however, be supposed that metaphysical ad 

 varices are always conditioned by scientific progress, and that the 



