In the simplest terms, an economy prospers through 2 ways – finding new natural resources and increasing human productivity. Just for understanding, let us assume that these are growing at just 2 percent every year. If the amount of money in the system remains the same, then, there will be a 2 percent degrowth in the price of goods and services each year! That will be terrible for the human morale and, in turn, to the economy because increased productivity and innovation is resulting in lower pay! So, there is a definite need to increase the money in the system as well.