CH. 21

THE THEORY OF PRICES

297

complicating factors set forth above.

We will consider each of them in turn. But thisprocedure must not be allowed to lead us into supposingthat they are, strictly speaking, independent. Forexample, the proportion, in which an increase ineffective demand is divided in its effect between in-creasing output and raising prices, may affect theway in which the quantity of money is related to thequantity of effective demand. Or, again, the differ-ences in the proportions, in which the remunerationsof different factors change, may influence the relationbetween the quantity of money and the quantity ofeffective demand. The object of our analysis is, notto provide a machine, or method of blind manipulation,which will furnish an infallible answer, but to provideourselves with an organised and orderly method ofthinking out particular problems; and, after we havereached a provisional conclusion by isolating thecomplicating factors one by one, we then have to goback on ourselves and allow, as well as we can, for theprobable interactions of the factors amongst themselves.This is the nature of economic thinking. Any otherway of applying our formal principles of thought (with-out which, however, we shall be lost in the wood) willlead us into error. It is a great fault of symbolicpseudo-mathematical methods of formalising a systemof economic analysis, such as we shall set down insection vi of this chapter, that they expresslyassume strict independence between the factors in-volved and lose all their cogency and authority if thishypothesis is disallowed; whereas, in ordinary dis-course, where we are not blindly manipulating butknow all the time what we are doing and what the wordsmean, we can keep “at the back of our heads” thenecessary reserves and qualifications and the adjust-ments which we shall have to make later on, in a wayin which we cannot keep complicated partial differ-entials “at the back” of several pages of algebra which