THE THEORY OF INTEREST

objective factor of a return over cost. Of course, even afterthe period of early exploitation is passed there are plentyof opportunities within the industry for variation in therates of return over cost, but they are no longer so con-spicuous.

Even when there is no exchange possible, as with Rob-inson Crusoe alone on his island, there will be dealingswith Nature. Crusoe may plant trees or build a boatand balance his immediate labor against his future sat-isfactions without the presence of any exchange proc-ess. It would have been possible, of course, to havebegun the presentation with Robinson Crusoe instead ofending with him. In that case, we should have first con-sidered the primitive facts of labor exerted for the sakeof future satisfaction, or their equivalent in berries. Wecould then bring in Man Friday, and proceed step bystep to the complications of modem civilization. Weshould have seen how the primitive cost and return typi-fied by labor and satisfaction became gradually hiddenin a mass of exchanges until today we think of both interms of money. The capitalist of today, instead of labor-ing for a future satisfaction, may simply abstain tempor-arily from a part of the satisfactions he could otherwiseenjoy and, with the money which he would have spentfor them, buy the labor to build a railway. The laboreris no longer the one who has to wait for the satisfactionsto follow the completion of the railway. He is paid inadvance and converts his pay into real wages very speed-ily, while the capitalist waits and receives the rewards forwaiting.

In all these and the other manifold exchange relationsthe terms are partly set by the principles of discount inrelation to impatience. But the primitive ingredients

[ 180 ]