Reality, in its quantitative aspect, must be considered as a system of populations... The general study of the equilibria and dynamics of populations seems to have no name; but as it has probably reached its highest development in the biological study known as 'ecology,' this name may well be given to it.

I have been gradually coming under the conviction, disturbing for a professional theorist, that there is no such thing as economics - there is only social science applied to economic problems.

Are we to regard the world of nature simply as a storehouse to be robbed for the immediate benefit of man?

Conflict may be defined as a situation of competition in which the parties are aware of the incompatibility of potential future positions, and in which each party wishes to occupy a position that is incompatible with the wishes of the other.

Deciding under uncertainty is bad enough, but deciding under an illusion of certainty is catastrophic.

[The notion of equilibrium] is a notion which can be employed usefully in varying degrees of looseness. It is an absolutely indispensable part of the toolbag of the economist and one which he can often contribute usefully to other sciences which are occasionally apt to get lost in the trackless exfoliations of purely dynamic systems.

Economic progress means the discovery and application of better ways of doing things to satisfy our wants. The piping of water to a household that previously dragged it from a well, the growing of two blades of grass where one grew before, the development of a power loom that enables one man to weave ten times as much as he could before, the use of steam power and electric power instead of horse or human power - all these things clearly represent economic progress.