THE APPLICATIONS OF SCIENCE 165 



a law, may be an object of contention when it is first 

 proposed, it is equally true that the difference of opinion 

 is always ultimately resolved. A theory may be doubted, 

 but while it is doubted it is not part of the firm fabric 

 of science ; but in the end it is always either definitely 

 accepted or definitely rejected. It is in this that science 

 differs from such studies as history or philosophy in 

 which controversies are perennial. There is an immense 

 body of science concerning which there is no doubt, 

 and that body includes both theories and laws ; there is 

 a smaller part concerning which dispute is still continu- 

 ing. It is only natural that this smaller part should 

 receive the greater share of explicit attention ; the other 

 and greater part we learn in our school and university 

 courses and find no need to discuss later, because it is a 

 matter of common knowledge with which all properly 

 informed persons are completely familiar ; it is the base 

 from which we proceed to establish new knowledge, and 

 the premiss on which we found our arguments concern- 

 ing it. The distinction between the twojpajts 



knowledge, that which is firmly established, and that 

 which is still doubtful, is perfectly clear and definite to 

 all who have been properly trained. The fact that doctors 

 differ in science, as in other things, does not affect the 

 equally important fact that in much the larger part of 

 their knowledge they agree. 



But a more serious objection may be raised. In the 

 opening chapters we concluded that science draws its 

 subject-matter from a limited portion of experience, and 

 that this limited portion necessarily excludes all that part 

 of our life which is of the most intimate interest to us. 

 It may be urged with force that while science may be in 

 possession of perfectly positive knowledge concerning 

 which every one who has studied the matter is in agree- 

 ment, yet this knowledge is entirely divorced from all 

 the affairs of practical life ; when science attempts to 



