Using the commons as a cesspool does not harm the general public under frontier conditions, because there is no public, the same behavior in a metropolis is unbearable.

Ecology is the overall science of which economics is a minor speciality.

The optimum population is, then, less than the maximum.

An attack on values is inevitably seen as an act of subversion.

A coldly rationalist individualist can deny that he has any obligation to make sacrifices for the future.

Value is a relative concept: the value of each action is determined by comparing it with other possible actions.

Ecological differentiation is the necessary condition for coexistence.