The economy operates within a finite world, so at some point, a problem of diminishing returns develops. In other words, it takes more and more effort (human labor and use of resources) to produce a given quantity of oil or food, or fresh water, or other desirable products. The problem of slowing economic growth is very closely related to the question: How can the limits we are reaching be expected to play out in a finite world? Many people imagine that we will “run out” of some necessary resource, such as oil, but we see the situation differently. Here are a few issues that may not be obvious.