identity of capital with things which are not capital goods at all, it is surely not desirable, least of all logically necessary, to deny the identity of capital with capital goods.

Surely, the facts are very simple. Material things during a certain phase come into that temporary relation to human well-being in which, as productive goods or capital goods, they serve human needs in indirect ways. They do not remain in this relation indefinitely, but gradually pass beyond it, while other things in turn enter into this relation. The notion of capital includes always the goods which are in this temporary relation. Capital is not, and never can be, anything other than the whole of these goods. Professor Clark builds up for himself logical obstacles, which are in fact no obstacles at all, and thereby prevents himself from grasping these simple facts in an equally simple way, and, in order to find an escape from the difficulties which he has thus created for himself, turns to devices which are no less superfluous than they are inconsistent with the facts. He peoples the world of reality with a new kind of thing which, in fact, does not exist, with a capital which has a real and "literal" existence and which also is "something material," and which, nevertheless, is something different from the capital goods. It is a capital to which Professor Clark believes himself entitled at a later time to ascribe effects of its own, which are not the effects of capital goods; and capital whose relation to capital goods, notwithstanding all the rich phraseology of its creator, never can be made clear to simple common sense.

For how can Professor Clark, side by side with the expressions just cited, continue to define his true capital as "embodied value," as "a permanent value in a shifting corporeal embodiment"? If capital, as he now unequivocally says, is a mass of capital goods, how can it be embodied in it? Seriously, can a thing be embodied in itself?

Professor Clark seems to be ever under the spell of his formula as to the permanence of true capital. He repeats again and again its "continuance" (p. 355): this supposedly unequivocal fact compels us, he thinks, to admit the existence of something different from capital goods. But is there anything so unequivocal in this formula? May it not be used loosely as well as strictly? Consider the example of the capital that lasts fifty years (p. 356): does he really maintain that there is a "continuance" of the same identical thing? If capital, which fifty years ago was "created" in the shape of a farm, exists to day in a grandchild's possession in the shape of a stock of silks, can and will Professor Clark assert with full scientific accuracy that the material thing which was capital fifty years ago and the material thing which is capital to-day are identical material things? Those men of affairs on whose expressions and conceptions Professor Clark is disposed to base his scientific system would probably say, with more or less hesitation and evasion: "In a certain sense the grandchild's stock of silks is the same capital as the grandfather's farm; but in another sense it is not the same. The farm was an agricultural capital: the silks are something quite different,-a commercial capital." It seems to me unmistakable that this infusion of subjective conceptions into the question of identity rests simply upon the play of our abstraction carried out in different directions. The varying answers are possible only because at one time "stress is laid" upon one circumstance, at another time is laid upon another, because we disregard or abstract from all other changes except those on which for the moment we "lay stress." An affirmative answer on this question of identity can be reached only if we make use of abstraction as against all the changes which, in fact, take place and destroy real identity. The

1 As to the material quality of Clark's capital, see the foot-note preceding.

identity of the capital that was created fifty years ago and of that now existing is not a brutal, unequivocal fact, but a flexible formula which can be adapted to the particular sort of abstraction which happens to be used.1

I must beg the reader's pardon if I weary him. But I venture to ask Professor Clark, and, if it be not superfluous, the reader also, to consider another concrete example, a house. A house, like any other constituent of Clark's true capital, is an entity whose existence continues notwithstanding change in its constituent parts. It can be repaired, sundry parts can be changed, new windows can be put in, a new roof added. It can be enlarged and rebuilt; can be taken to pieces and put up again; can be put up on the same place and with the same materials or with only partial use of the old site and the old materials. How long can we say that it remains the "same" house? Would one receive an unanimous answer to this question from all quarters, or a series of somewhat different answers, each one with its justification? Must we not receive different answers according to the different point of view from which they were given? One sort of answer might come from the lawyer who had occasion to consider a mortgage on the house, another from the historian who had to decide whether "this" was the house in which a poet died. The philologist, the physicist, the logician, each from his point of view might give a different answer. Each would abstract from all considerations except those relevant for his purpose. We thus might have half a dozen different

1 Incidentally, I would remark that I do not share Professor Clark's opinion as to the complete change in the thought and speech of every-day life which, in his view, must set in if my opinion should prevail. I am in no way opposed to the use of abstract conceptions, which are indispensable alike for the man of science and for the man of affairs, nor am I opposed to the use of figurative expressions. But I am opposed to any practise in science of using abstractions and figures of speech as if they were realities. In any case it is not to be believed that any man of affairs would accede to Professor Clark's views, and seriously be of opinion that, when he owns a factory, his property consists of any other "material thing" than the capital goods of which the factory consists.

answers on the question of identity. None the less, it is clear that we have not to do with six different material things, but with the result of six abstractions, each justified for its particular purpose. Thus the formula as to the "continuance" of house and of capital rests not upon the solid basis of literally and unmistakably identical facts, but upon fluctuating subjective points of view. Hence Professor Clark may take comfort and assure himself that neither he nor economic science is under any logical compulsion to assume in the world of reality the existence of "permanent" things which correspond to his formula.

I must pay my homage to Clark as a man of letters. Among the endless analogies which might be chosen, he has selected, in his examples of the river Hudson and of the human beings who reach the age of fifty or sixty, precisely those which might dispose the reader in favor of his view. As to his example of living beings, to be sure something might depend as to one's views as to their "identity," -on one's conceptions as to the "soul" and as to a "unit of consciousness" running through the various phases of life. These are considerations which cannot apply to the loose combinations of inanimate material things which we may elevate, according to our point of view, into "unities" or "entities." Such considerations even in their own field support at the best a spiritual dualism, but no hypothesis of the co-existence of two material things. It is better to leave to the other sciences which have to deal with such problems the riddles as to life and soul, and not to import these into the consideration of the very simple facts which suggest no such riddles. I suspect I do no injustice to my opponent's brilliant art of exposition by suggesting that he ever leads the reader to view the controverted questions through skilfully selected lenses which lead to that same optical illusion under which Professor Clark himself suffers and which he naturally wishes to impose on his readers.

I trust I have shown that the delusion so created disappears as soon as one steadfastly looks at other phases of the problem whose consideration my honored opponent has hitherto unremittingly avoided.

Doubtless all this belongs rather to logic than to economics. I cannot escape the impression that the logicians, in case controversy of this sort should arise among them, would dispose of it very summarily. I suspect that in the specialized field of logic a decision has long been reached, in regard to controversies of this sort, in the shape of rules and examples for learners, so familiar that they are no longer worth discussing. But other parts of our controversy touch matters which belong, if not exclusively, at least in their main content, to the field of economics.

First of all, I would remark that my distinguished opponent has a different and a less exacting conception than my own as to what is the "explanation" of a phenomenon. Only in this way can I understand what he says (for example, on page 362) in a somewhat ironical and would-be victorious tone. He mentions that the money receipts of a plough factory must suffice to buy new emery wheels and other tools that are worn out, to replace what has been spent for wages, including wages of supervision, and, finally, leave something as a return on capital. Such facts no one denies, and, in order to convince me of their "correctness," it was hardly necessary to adduce the "discoveries" which my honored opponent made in his own experience with such matters. But I confess I am unable to see why Professor Clark speaks of the "conclusiveness" of an insight into these facts. He seems to find in these facts an explanation, or at least a long step toward an explanation, of interest on capital: whereas I see in them only a statement of the facts to be explained. I can only ascribe it to the absence of a clear discrimination between the ascertainment and the explanation of a fact that,