The Universal Declaration of Human Rights describes the family as the natural and fundamental unit of society. [Article 16] It follows that any choice and decision with regard to the size of the family must irrevocably rest with the family itself, and cannot be made by anyone else. —U Thant, Statement on Population by UN Secretary-General
This parental reproductive freedom was endorsed by the 1968 UN Proclamation of Tehran. Hardin advocates repudiation of this element of the Proclamation.
To make the case for "no technical solutions," Hardin notes the limits placed on the availability of energy (and material resources) on Earth, and also the consequences of these limits for "quality of life." To maximize population, one needs to minimize resources spent on anything other than simple survival, and vice versa. Consequently, he concludes that there is no foreseeable technical solution to increasing both human populations and their standard of living on a finite planet.
From this point, Hardin switches to non-technical or resource management solutions to population and resource problems. As a means of illustrating these, he introduces a hypothetical example of a pasture shared by local herders, which he calls a commons. Assuming that the herders only wish is yield maximization, they will increase their herd size whenever possible. The marginal utility of each additional animal has both a positive and negative component:
Positive: the herder receives all of the proceeds from each additional animal. Negative: the pasture is slightly degraded by each additional animal.
Crucially, division of these costs and benefits is unequal: the individual herder gains all of the advantage, but the disadvantage is shared among all herders using the pasture. Assuming that the negative impact on the herder's other animals is less than the income of a new one, the rational course of action for each individual herder will always be herd expansion. Since all herders reach the same conclusion, overgrazing is inevitable. Each herder will continue to impose costs on all of the others, until the pasture is depleted.
Because this sequence of events follows predictably from the behavior of the…