of some Doctrines of Political Economy. 195 



distinctly the assumptions, and these thus were open to a thorough 

 examination ; it made the reasonings almost infallible ; and it 

 gave results which could be compared with practice so as to shew 

 whether the problem was approximately solved or not. It ap- 

 pears I think that the sciences of Mechanics and Political Economy 

 are so far analogous, that something of the same advantage may 

 ))e looked for from the application of mathematics in the case of 

 Political Economy. And this must be remarked, that in this we 

 are so far from claiming for it the rank of a science mathe- 

 matically demonstrated, that we do not thus assert it to be a 

 near approximation to the business of the world, any more than 

 the doctrines of Mechanics are to actual practice, if we neglect 

 friction and resistance, and the imperfection of materials, and sup- 

 pose moreover the laws of motion to be questionable. But we 

 hold this method of investigation to be the best way of separating 

 the theories which have been advanced, into the different kinds 

 of truth, or of falsehood, of which they may happen to consist. 

 And we conceive, that by doing this we shall better enable men 

 to form their opinions of the value of these several parts. 



5. The portion of the subject on which I wish at present 

 to treat, belongs to the second of the processes liable to error, 

 of which I have mentioned three ; namely, the deduction of con- 

 clusions from fundamental propositions. There are certain reason- 

 ings concerning rent and taxes, which are urged by their respective 

 advocates; each founded on the same very simple principles; and 

 each leading to various conclusions: the conclusions of one set 

 of reasoners are opposite to those of another. The principles of 

 the different parties are so nearly identical, that it is manifest that 

 their difi'erence arises from some peculiarity introduced in a sub- 

 .sequent part of the investigation, and it is my intention to employ 

 the processes of mathematics to point out where this latent as- 

 sumption may reside. 



B B 2 



