CLARK'S REFORMULATION OF THE CAPITAL CONCEPT 137 
employing class) with “labor” (the wage earning class), it gives 
no hint or warning of the author’s purpose to replace with a new 
conception the conventional notion of capital as an economic 
factor of production. That came in 1888 seemingly out of a 
clear sky. 
Let us first restate, as briefly as we can, just what the thought 
was, and then seek to account for its appearance at that time. 
The more essential points in which Clark departed from the then 
prevalent views of capital may be reduced to five. He said: 
(a) The conventional capital concept is ambiguous, meaning 
both “pure” capital and concrete “capital goods.” 
(b) “Pure capital,” is a fund of value. 
(c) Land in all its forms is a part of concrete capital. 
(d) All concrete goods yield rents. 
(ej All pure capital yields interest. 
(a) Clark declared that economic science had and was using 
two unlike conceptions of capital, while believing that it had 
but one. Hence ambiguity, confusion, “logomachies.” Clark 
would frankly accept both concepts, clarify them, and distinguish 
them by somewhat different names. One is the abstract, the 
other is the concrete concept. The abstract conception, para- 
doxically, is the one “employed in business a hundred times 
where the concrete conception is employed once’; * whereas “the 
actual practice of economic science has been to first define 
capital in the concrete, and then, in the problems connected with 
it, to tacitly substitute again and again the abstract conception.” 
(b) Clark calls capital in the abstract sense “pure capital,” 
which is a “fund,” a “single entity” common to all the concrete 
forms of capital. This fund or entity is expressly declared to be 
“effective social utility,” but this mysterious notion is repeatedly 
spoken of more simply though somewhat puzzlingly as “the value 
that a business man invests” in the various instruments and 
materials he uses. This is the value conception of capital in 
contrast with the concrete goods conception as defined by the 
conventional definition of the older political economy. 
(c) Clark classed as concrete capital not merely the artificial, 
humanly “produced means of production,” but all instruments 
and materials, including land and all other natural agents. 
* Op. cit., pp. 11-12.