And this leads us to our second, but indirect, proof that Kent as well as Profits and Wages enters into price. For just as in a thermometer there are degrees of frost below the freezing point - which for the nonce we may assume as the zero or 'margin of indifference' between heat and cold - so in the same way there are degrees of sterility or uselessness below the no-rent land on the margin of cultivation; and as the degrees of frost enter into the quantity of vegetation quite as much as the degrees of heat, only that they do so by lessening its amount instead of increasing it; so there can be no question that land below the 'margin of cultivation ' enters into price, inasmuch as the costs incurred, say, in pumping out a water-flooded mine; or in keeping a patch of no-rent land permanently drained, or free from thistles, to prevent it injuring the adjoining rent-paying patches; or in paying extra insurance against floods, volcanic eruptions, earthquakes, or what not, raises the price; and this in turn shifts the zero-margin from which rent will begin to be paid, precisely in the same way as the use of old rickety machines which do not pay for their repairs, or old worn out labourers who do not pay by their work for the wages they receive, also affects price, and shifts the zero-point from which Capital will begin to receive differences of profits, and Labour to receive wages above its keep; like those ghosts in Hamlet and Macbeth, or the ancestral spirits of the Japanese religion, which though dead, yet enter into the works and lives of men.

If, then, in the present stage of industrial development every product is the result of the conjoined operation of the three factors of Land, Capital, and Labour; and if any change occurring in any one of them alters its price, - whether by lowering or raising it, whether directly by itself or indirectly by its reactions on the other factors; - it follows that all three factors alike must enter into price. And this, again, leads us to point out once more how curiously the symbol of the divided stick, which has been the bane of the orthodox Economy from the beginning, is still found in its latest and most differentiated developments, and how it falsifies the solution of every problem into which it enters. In the present case it takes the form of drawing an arbitrary line or ' margin of indifference,' as it is called, like the freezing point on a thermometer, across the centre or lower end of their instruments of production; all above this point being regarded as a positive or plus quantity, and all below it as a negative or minus one; with the absurd result that while all below it enters into price by increasing the costs and lessening the supply, and all above it by increasing the supply and lessening the costs, nothing on the imaginary marginal line itself enters into price at all.

It is as if they had arrested a cannon ball at some point in its flight, called that point zero, and then agreed, as in the paradox of the ' flying arrow,' that while during all the rest of its flight on either side of this imaginary point the ball was in motion, at this point itself it was at rest, and not moving at all! And from this, again, 'it follows that the academical economists can get no true law of Distribution from keeping the instruments of production apart, and manipulating them by means of these imaginary zero-margins of no-rent and no-profit-earning abstractions; or in other words, that in a purely dynamical science you cannot begin with mere statical subdivisions ending in imaginary 'margins of indifference,' etc., and then think you will allow for the dynamical complications afterwards, for that would involve you from the start as we have seen, in all the fallacies of the 'Achilles and tortoise' and 'flying arrow' paradoxes which come directly from the use of these statical units and margins, and from which you cannot afterwards escape; on the contrary you must begin from the start with a dynamical construction, in which the great motor factors, or instruments of production, planted at different points around the circumference of the wheel, propagate their influences from one to the other in a continuous movement, without pause or break; whether this dynamical construction take the form we have given it in this book of a running wheel, or some other and better one which it is for the future of Political Economy to discover; the statical elements being brought in, as we have already seen, in the form of obstructions at this or that point to the free running of the wheel.

So much, then, for our first problem, namely as to whether Rent enters into price or not; - and it is evident that if we are right, Professor Marshall, who with his statical method and imaginary marginal levels denies not only that Rent in general enters into price, but that even monopoly or scarcity rent enters into it, - on the ground that by his 'law of substitution' there will always be found some substitute which will by competition keep the price down to a no-rent margin, - has in these later days of the bankruptcy of the old orthodox Economy, wandered far from the path. The issue, then, presented to the reader for his consideration in this problem of Rent is quite clear; - The orthodox and academical economists, proceeding by their statical method of the divided stick, and having followed Jevons in subdividing this again into infinitesimal increments ending in ' final units,' 'margins of indifference,' etc., hold that while Profits and Wages enter into the price of a commodity, Rent does not; my solution, on the contrary, founded on the dynamical method from the start, is that Rent, as well as Profits and Wages, enters into price; and that if it does not, neither do they, inasmuch as the marginal method which has been applied to Rent, can equally well, and by the same principle, be applied to them.