As long as man was small in numbers and limited in technology, he could realistically regard the earth as an infinite reservoir, an infinite source of inputs and an infinite cesspool for outputs. Today we can no longer make this assumption. Earth has become a space ship, not only in our imagination but also in the hard realities of the social, biological, and physical system in which man is enmeshed.

Equilibrium is a figment of the human imagination.

Humble, honest, ignorance is one of the finest flowers of the human spirit

The proposition that the meek (that is the adaptable and serviceable), inherit the earth is not merely a wishful sentiment of religion, but an iron law of evolution.

Political conflict rests to a very large extent on a universal ignorance of consequences, as the people who are benefited by any particular act or policy are rarely those who struggled for it, and the people who are injured are rarely those who opposed it.

It is clear that the building of models is not a purely mechanical process but requires skill of a high order - not merely mathematical skill but a sensitivity to the relative importance of different factors and a critical, almost an artistic, faculty in the selection of behaviour equations which are reasonable, tentative hypotheses in explaining the behaviour of actual economies.

Mathematics brought rigor to Economics. Unfortunately, it also brought mortis.