Optimum Population Level

Try this thought experiment: You and few dozen fellow adventurers have decided to establish a new society on an unpopulated island. What would you consider to be the optimum population for your island?

The island is large, and environmental limits are not an immediate concern. If your only objective is to maximize the average individual net gains (ING) of this society's members, at what point will you stop the growth of its population?

Although a rigorous definition of "optimal population" is difficult to formulate, it is reasonable to state that a population is too low if a society does not have sufficient opportunities for cooperation, specialization, and exchange to permit average ING to reach its maximum attainable level.

Conversely, population is too high if these opportunities have been largely exhausted and the increases in crowding and stress cause average ING to decline.

Many standard economists have adopted a similar perspective. The following explanation by Robert Solow is typical:

We all know the bad consequences of too large a population: crowding, congestion, excessive pollution, the disappearance of open space — that is why the curve of average well-being eventually turns down at large population sizes. Why does the curve ever climb to a peak in the first place? The generic reason is what economists call economies of scale, because it takes a population of a certain size and density to support an efficient chemical industry, or publishing industry, or symphony orchestra, or engineering university, or airline, or computer hardware and software industry …But after all, it only takes a population of a certain size or density to get the benefit of these economies of scale.1

ENL calls such factors scale effects, and defines the optimum population as the level where the health advantages associated with an increased population have been exhausted and where average ING has reached its peak before stabilizing and eventually declining.

In ENL terms, scale effects arise because they improve economic conditions.

In other words, a rising population can, through specialization and exchange, lead to higher potential value and effectual value, and to lower input costs. The value and cost curves in this situation will therefore shift outward. These outward shifts, insofar as they reflect an increase in per capita gains, constitute a rising average ING.

But this is clearly not the entire story. As a standard thinker attuned to capitalist realities, Solow assumes that a society must be technologically sophisticated, and will therefore require a chemical industry and an engineering university.

ENL, on the other hand, subscribes to technological neutrality. In this context the choice of technological complexity is not automatic, but must be made consciously by a society's members.

In the island example, people must first determine what kind of society they are trying to form. Do they want one that is simple and close to nature, or one that is complex and less attuned to the natural world?

If the group decides that technological complexity should be low, then a relatively low population will provide adequate opportunities for cooperation, specialization, and so forth. If it decides that technological complexity should be high, then a relatively high population will be required for these purposes. The following figure shows the difference.

Optimum population
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Due to scale effects, average ING will first increase, then level off, and finally decrease. The optimum population is reached when ING is at its maximum attainable level. This optimum level rises as technological complexity increases.

This graph is somewhat different from other ENL graphs. The horizontal axis is the population level and the vertical axis is a society's average ING, which is measured in total rather than marginal units. We are thus tracking changes in average ING as population increases.

The rate at which the curve rises depends on the society's chosen level of technological complexity.

A technologically simple society will quickly reach its optimum population level because relatively few people are required to develop and operate such an economy. The curve will therefore rise steeply before stabilizing.

A complex society will reach its optimum population level more slowly because of population scale factors, and the curve will therefore rise more gradually to its optimum point.

A critical point is this: aside from the increase in average ING, there is no reason within ENL's analytical scope for a population level to rise.

There can of course be compelling political, military, or other reasons to do so, but these are not economic factors as understood within the framework and cannot be considered here. From the perspective of ENL logic, which seeks to maximize individual well-being, a population should never exceed its optimum level.

This point underscores one of the options available to achieve long-term decreases in natural flow rates. Three major options are available: higher ecological efficiencies, economic re-organization, and lower consumption of wants. An additional suggestion was to shift society to a lower level of technological complexity, and it can now be seen why this change is so compelling.

Lower technological complexity will not only reduce flow rates for the existing population, it will lower the optimum population itself, thereby encouraging the shift to a smaller and less resource-hungry society. This choice thus offers a double benefit for long-term resource conservation and the overall preservation of the environment.


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