INCIDENCE OF RATES AND TAXES 117 



it were very extreme and the circumstances 

 peculiar. We are then obliged, in the first 

 place, to attack the problem by what is 

 called the deductive method. We must 

 try to isolate the principal forces involved, 

 and discover their effects in the absence 

 of what are called disturbing causes. 

 When we have discovered the resultant 

 tendency of these forces under the assumed 

 simple conditions, we can consider how 

 far they are modified in practice by the 

 interference of the disturbing causes. 



You will observe that as regards any 

 particular problem, the application of this 

 method is not complete until we have 

 taken account of all the experience avail- 

 able. The economic theorist does no more 

 than provide the man of affairs with lines 

 of inquiry, and without guiding clues of 

 some kind, the facts cannot be utilised 

 at all. 



