"It appears we can safely conclude money is not a perpetual motion machine producing wealth with a valid claim on society to the end of time: …it is only necessary to point out that a perpetual motion machine is an impossibility. A man with, say, £20,000 invested at 5 per cent is in perpetual enjoyment without work of an income of £1,000 a year, and his heirs and successors after him. Consuming wealth every day of their lives, they always have the same amount as at first. This is not physics and it is not economics. Like all alleged examples of perpetual motion, it is a trick.
Real wealth requires energy to maintain over time, as well as to create. Debt and interest do not; they are social and mathematical constructions. Real wealth is subject to entropic forces, e.g. rot and rust, as its material components revert over time to a state of maximum entropy. As Soddy puts it “… wealth, unlike debt, rots if it is accumulated.
It is the perpetual motion view of money, capital and debt deeply imbedded in orthodox economics – to which Soddy objected, particularly to the way money is created under the system of fractional reserve banking:
The common sense of these laws is that a perpetual motion machine is not possible. To produce wealth energy must be expended or consumed. … To this common sense truism that, in the world ruled over by physical laws, it is impossible to get something for nothing, modern money is an apparent outstanding exception, the elucidation of which throws a flood of light on the nature of money and suffices to rob it for ever of its robe of mystery and let us hope, of its power of evil. Money to most people still conveys the idea of coins, but, except as small change, coins are obsolete. In so far as modern money has any tangible physical existence, and by far the greater part has none, it is a paper token, which like a postage stamp, costs next to nothing to make, and which has some value printed on it.