One of the most important skills of the economist, therefore, is that of simplification of the model. Two important methods of simplification have been developed by economists. One is the method of partial equilibrium analysis (or microeconomics), generally associated with the name of Alfred Marshall and the other is the method of aggregation (or macro-economics), associated with the name of John Maynard Keynes.

Conventions of generality and mathematical elegance may be just as much barriers to the attainment and diffusion of knowledge as may contentment with particularity and literary vagueness... It may well be that the slovenly and literary borderland between economics and sociology will be the most fruitful building ground during the years to come and that mathematical economics will remain too flawless in its perfection to be very fruitful.

The trouble with taxonomic boxes is... that that they tend to be empty, however beautiful they are on the outside.

Physicists only talk to physicists, economists to economists-worse still, nuclear physicists only talk to nuclear physicists and econometricians to econometricians. One wonders sometimes if science will not grind to a stop in an assemblage of walled-in hermits, each mumbling to himself words in a private language that only he can understand.

The right to have children should be a marketable commodity, bought and traded by individuals but absolutely limited by the state.

There is a quiet, open place in the depths of the mind, to which we can go many times in the day and lift up our soul in praise, thankfulness and conscious unity. With practise this God-ward turn of the mind becomes an almost constant direction, underlying all our other activities.

[The loss-of-strength gradient is] the degree to which military and political power diminishes as we move a unit distance away from its home base.