Regarded in that light,the labours of Mill and Cairnes on the method of the science,though intrinsically unsound,had animportant negative effect.They let down the old political economy from its traditional position,and reduced its extravagantpretensions by two modifications of commonly accepted views.First,whilst Ricardo had never doubted that in all hisreasonings he was dealing with human beings as they actually exist,they showed that the science,as he conceived it,must beregarded as a purely hypothetic one,Its deductions are based on unreal,or at least one-sided,assumptions,the mostessential of which is that of the existence of the so-called "economic man",a being who is influenced by two motives only,that of acquiring wealth and that of avoiding exertion;and only so far as the premises framed on this conception correspondwith fact can the conclusions be depended on in practice.Senior in vain protested against such a view of the science,which,as he saw,compromised its social efficacy,.whilst Torrens,who had previously combated the doctrines of Ricardo,hailedMill's new presentation of political economy as enabling him,whilst in one sense rejecting those doctrines,in another senseto accept them.Secondly,beside economic science,it had often been said,stands an economic art,--the former ascertainingtruths.respecting the laws of economic phenomena,the latter prescribing the right kind of economic action;and many hadassumed that,the former being given,the latter is also in our possession-that,in fact,we have only to convert theorems intoprecepts,and the work is done.But Mill and Cairnes made it plain that this statement could not be accepted,that action canno more in the economic world than in any other province of life be regulated by considerations borrowed from onedepartment of things only;that economics can suggest ideas which are to be kept in view,but that,standing alone,it cannotdirect conduct--an office for which a wider prospect of human affairs is required.This matter is best elucidated by areference to Comte's classification,or rather hierarchical arrangement,of the sciences.Beginning with the least complex,mathematics,we rise successively to astronomy,physics,chemistry,thence to biology,and from it again to sociology.In thecourse of this ascent we come upon all the great laws which regulate the phenomena of the inorganic world,of organisedbeings,and of society.A further step,however,remains to be taken-namely,to morals,.and at this point the provinces oftheory and practice tend to coincide,because every element of conduct has to be considered in relation to the general good.
In the final synthesis all the previous analyses have to be used as instrumental,in order to determine how every real qualityof things or men may be made to converge to the welfare of Humanity.
Cairnes's most important economic publication was his last,entitled Some Leading Principles of Political Economy newlyExpounded ,1874.In this work,which does not profess to be a complete treatise on the science,he criticises and emends thestatements which preceding writers had given of some of its principal doctrines,and treats elaborately of the limitations withwhich they are to be understood,and the exceptions to them which may be produced by special circumstances.Whilstmarked by great ability,it affords evidence of what has been justly observed as a weakness in Cairnes's mental constitution--his "deficiency in intellectual sympathy,"and consequent frequent inability to see more than one side of a truth.
