All would be well is all the money saved were invested. Then all the money would be spent the second time around. It would not all be spent by consumers, but it would be spent by somebody; it would be spent by consumers and investors combined (leaving aside as not essential to the present point government spending and foreign trade).

Keynes locates the problem in the tendency of investment to lag behind savings. Differing from Narayan’s focus on worker purchasing power, Keynes locates the problem in total purchasing power, also known as aggregate demand. If there is plenty of investment, then the circulation process can continue indefinitely, with their always being enough revenue in somebody’s hands to carry on a steady stream of sales transactions producing for ever and ever steady streams of revenue. This reasoning, this mindset, this institutional framework, lead to the growth imperative.

Whatever other reasons a modern economy may have for wanting to grow, there is an accounting identity that compels it to grow. There has to be enough investment to sop up savings and thus ward off what is called a “downturn” where goods cannot be sold and workers cannot be employed. But investment only happens when investors rationally believe that at some future date they, or the enterprise they are investing in, will be the owners of some product that can be sold at a profit. Hence more and more products must be brought to market for the sake of the stability of the system, independently of the ethical or ecological reasons which may or may not justify bringing to market more products or bringing to market any particular product. The government can prohibit the production of products it might deem harmful, such as cigarettes or sports utility vehicles or pornography or violent television shows seen by children, but if it prohibits them it makes compliance with the growth imperative harder to achieve. Then some other profitable ways to invest capital must be found to make up for the prohibition against making money by means the legislature deems harmful.