To understand the relationship between producing, consuming, saving and investment, it is useful to start with a simple story.
Imagine a Robinson Crusoe economy — just one person in it. RC’s consumption is limited to what he can produce by fishing, hunting and gathering. He allocates his time either laboring or enjoying leisure. If he consumes less than what he produced during a particular period, he can save that for later consumption.
For example, if he has saved some fish, he can forego fishing and instead use that time to fashion a spear for hunting. That means, his savings allowed him time to invest in creating that spear. He “converted” his saved fish into a spear. The spear is what is called “capital” — something that is not directly consumed but is used for producing goods for consumption (or even more capital.) His spear will increase his productivity in hunting, thus enlarging his consumption possibility. Continue reading