ENGINEERING AND PURE SCIENCE — SWANN 205 



amperes per square centimeter in the one direction and a million mil- 

 lion amperes per square centimeter in the other direction. The tele- 

 phone current constitutes an upsetting of the balance to the extent 

 of one-hundredth of a millionth of an ampere per square centimeter, 

 or about one part in a hundred million million million. Then if 

 this one part in a hundred million million million is at fault by one 

 part in a thousand, we ring up the telephone company and complain 

 that the quality of the speech is faulty. 



In the realm of pure experience, one has frequently started out with 

 something which is very complicated at the beginning. By trying 

 this and that, one has arrived at a number of procedures which are 

 not unrelated, which in some cases are redundant, and which in others 

 are even inconsistent with one another, and yet, through the process 

 of trial and error and much lapse of time, there has resulted a set of 

 operations and procedures that work in reasonably satisfactory man- 

 ner. That which we call understanding is now much less fundamen- 

 tal and, indeed, less powerful than the understanding of the scientist, 

 but is in some sense effective. Our old violinist can certainly play his 

 instrument and make it sound good. He tells his student to imbue his 

 soul with the spirit of good tone and good tone will come from the 

 instrument. The student tries to follow this advice. He does a lot of 

 wrong things and the master lambastes him continually with all sorts 

 of other criticisms. He tells him that he slouches too much when he 

 plays — that he is lazy — that unless he holds his bow more firmly the 

 spirit of tone in his soul cannot permeate through to the instrument. 

 And so, as a result of a lot of trials and errors and of doing this and 

 that, sometimes consciously and sometimes unconsciously, the student 

 succeeds in producing the good tone. Possibly he still retains the 

 feeling that his soul produced the tone, and it does no harm if he 

 should think that, so long as the idea in its implementation is supple- 

 mented, consciously or unconsciously, by all that heterogeneous con- 

 glomeration of other things which really conspire to produce the 

 ultimate end. 



THE NATURE OF PHYSICAL LAWS 



As a physicist I seek a logical framework of knowledge in which all 

 parts of my science are related in unambiguous ways. I am unhappy 

 about two different criteria bearing upon the same subject unless I can 

 understand clearly whether they are independent or related. 



And yet, out of this completely formulated system of laws which 

 represents my ideal, I could obviously pick certain isolated elements 

 and put them into forms which would stand by themselves and which 

 would hide their relationship. These isolated elements could well 

 serve as a useful guide to the artisan or general practical man even 



