949 
of Edinburgh, Session 1883-84. 
being, as we have seen, complex mixtures of ideas of every possible 
order, which, from the present point of view, are to be regarded as 
material to be disentangled and rearranged on the plan above out- 
lined into bodies of principles dealing with each successive aspect 
of the subject. Those principles once extricated, however, we 
obtain a key to the mode of construction of these systems, and an 
explanation of their incompleteness — each school, as was already 
pointed out, 'having grasped principles chiefly referable to one order 
only, and having used these to the practical exclusion of principles 
belonging to other orders. Hence such efforts as to restrict the 
domain of economics to questions of statistics, value, or exchange ; 
and the attempt thus to solve all problems is obviously incomplete. 
Similarly, the restriction of the subject to material wealth, Avithout 
consideration of the organisms of which the occupations, rate of repro- 
duction, mode of competition, &c., furnish biologico-economic prin- 
ciples. So with the investigation of biological principles without heed 
of the next order of factors — the psychological principles — or the very 
frequent attempts at completing a system, by the aid indeed of biolo- 
gical and psychological considerations, but without passing from the 
study of the individual to that of the higher unit — the society — 
with which the sociological principles are alone concerned. These 
are all examples of an attempt on the part of each preliminary 
science to annex the province of the succeeding one, an error which 
of necessity vitiates the system thus obtained. To this intrusion of 
each preliminary science upon the domain of its ascending successor, 
the term “ materialism^ though generally restricted to the attempt 
to reduce all sociology and morals to biology and physics, has with 
great advantage been sometimes extended. 
§ 13. The existing systems of economics are not only vitiated by 
this error of some form of “ materialism,” but also largely by the 
converse and if possible more serious error, that of attempting to 
make any one science do duty for those which underlie it, — which 
may conveniently be termed ‘‘ transcendentalism^ The attempts at 
system vitiated through the error of “ materialism,” which we have 
just been criticising, have largely indeed been due to an even earlier 
prevalence of “transcendentalism.” The man of moral bias, in at- 
tempting to construct a perfectly moral theory of economics without 
full and constant reference to the facts of exchange, of production, 
