"There are two main ways of buying a new car. One is to save up the cost little by little and get the new car when the money is all there. The other is to get the car now and defer paying the cost by resorting to some arrangement that permits us to do so and then save the money and pay the cost some time in the future. If the arrangement were not expensive, everybody would rather have the car now than later. We call this "time preference". It seems to be a very basic human trait. If instead of time preference we had "time indifference," while money we saved brought a return in interest, rent and dividend, we would all starve to death, for we would by definition always prefer to save the marginal dollar and earn a return of a few cents on it than earn no return at all and spend the dollar on present consumption that we did not prefer to future consumption."