But as regards these impossible conditions of Walker and Marshall, what are we to say! In the first place they are right in trying to simplify their problem by reducing all its factors to a common denomination as it were, with the object of finding out their law, but they must be sure, first, that no important factor has been left out; and in leaving out Consumption, their labours have been rendered futile and their deductions false. But even had they recognised Consumption as a definite factor, this simplification of the problem would have availed them nothing, so long as they kept their factors all on a dead level, as in a post-mortem room, as parts of a statical theorem instead of a living, moving, dynamical organism. For although Statically you may reduce a line to a number of points or units lying side by side, you still have missed something in the line, namely the dynamical power which runs them all together. In the same way in a dynamical Science like Political Economy, which has to deal with quantities of commodities and services continually being produced, consumed, and reproduced, you may have omitted none of the essential factors, and yet unless in every practical problem you can manage somehow to catch the dynamical power which keeps all the factors moving and runs them all together as it were, no mere reduction of them to their separate statical units will avail for a true solution.

This we abundantly demonstrated, for example, in our discussion on Free Trade and Protection, where we saw that the fallacy of the whole Free Trade argument reduced itself precisely to this leaving out of the motor-power, namely the powers of Nature embodied in the instruments of production, thereby reducing it to a question of the passage to-and-fro of the dead products of these instruments, to which alone statical methods, - with their apparatus of discrete units and increments thus broken up into a series of separate points instead of forming part of a continuous movement - are applicable, and which would land us at every point in our demonstration in the fallacies of the 'Achilles and tortoise,' and the ' flying arrow ' puzzles. And so it is with the problem of Value; and even although in this particular instance Professor Marshall recognised the dynamical element of Consumption as a factor in its solution, he could not have solved the problem until he had thrown all the other factors on the wheel, and so allowed the dynamical elements hidden in them to disclose themselves in its revolutions; thus converting all these factors alike into dynamical instead of statical ones.

It is true that I have myself in this volume tried to simplify the immense complexity of the subject-matter of the Science by first postulating an ideal wheel, equally balanced, and moving continuously like the heavenly bodies without friction in an aetherial medium, where competition is absolutely free, where all the factors have equal elasticity, and where all are kept in proportion to each other by the very revolutions of the wheel itself. But this, it is to be observed, is a dynamical construction, and is, as I shall attempt to prove later, the true method of the Science; and it is from this ideal wheel with its motor powers that I have deduced the laws of the Applied Science, where all irregularities are explained by obstructions at this or that point to its free running. So that by my method it is only these obstructions that are relegated to the category of 'other things being equal.' The academical economists, on the other hand, begin at the other end as it were, and hope by equalizing the conditions of the problem by means of marginal units and increments, either to do away altogether with the great driving dynamical forces of Consumption, on the one hand, and of Inventions and improvements in the instruments of production on the other, as well as of Monopoly and combinations everywhere; or else to reduce these to so subsidiary a position that they can be disposed of, or allowed for afterwards, under their category of 'other things being equal.' Professor Marshall, for example, thinks that he can solve the problem of Value by equalizing the conditions of competition; and this he proposes to do by equalizing the skill of the labourer, the amount of capital employed, the period of its investment, and the rate of profit.

But when he has done this, what chance is there of his finding the element of 'forced gain' which enters into Value from the combinations which are now everywhere taking the place of unlimited free competition, and which end either in partial or complete monopolies? Or again, how is he going to get a law of Value by excluding at the outset, as we have seen, the element of Consumption from his list of factors, when Consumption, as we have all along attempted to show, is the motor driving power of the whole wheel of wealth; its variations not only entering into Value, under their common designation of 'demand,' - quite as much so as difficulties of Production, ending in scarcity, enter into it under the common designation of 'supply,' - but actually helping to determine that 'supply ' by the stimulus given by increased consumption to inventions and improvements in production, etc? So that we have this curious result; - that while the whole problem of Value and of definite market-price is practically covered by the three great dynamical factors of Consumption on the one hand, of Inventions and improvements in the instruments of production on the other, and of Monopoly more or less operative everywhere; the academical economists have thrust all these into the background, as if they were the merest side-issues of the problem; while the primacy and place of honour in its solution is given to such considerations, as how the separate products of these living dynamical factors operate - such as the existing stock of commodities on hand, the quantity of money in circulation, the existence of substitutes or other occupations for capital or labour to fall back upon, the lengths of the periods of investment of capital, the rates of its profits, the state of the labour-market, etc. - a mere distracted miscellany of dead particulars, without central living powers to draw them together and impose proportion and limitations on them; all of them, it is true, affording valuable indications, in their way, of how the matter stands when once you have the key to them, but apt to be as misleading otherwise as if you were to try and determine the staying power of foxes by the respective lengths of their tails! And it is from wandering in the mazes of such outlying distracted particulars, that we have Professor Marshall not only not seeing, but actually denying, that Consumption can enter as a definite factor into any economic problem whatever; denying, too, that scarcity rents, as well as differential ones, enter into price; or that a monopoly, the result of Combination, can enter into it; or again that Trades-Unions can raise the rate of wages, etc.; - and all on the ground that a 'substitute ' will always somewhere be found, to grind them down to the common level by competition again.