I admit that these terms and the diagrams connected with them repel some readers, and fill others with the vain imagination that they have mastered difficult economics problems, when really they have done little more than learn the language in which parts of those problems can be expressed, and the machinery by which they can be handled. When the actual conditions of particular problems have not been studied, such knowledge is little better than a derrick for sinking oil-wells erected where there are no oil-bearing strata.

Nature's action is complex: and nothing is gained in the long run by pretending that it is simple, and trying to describe it in a series of elementary propositions.

But if inventions have increased man's power over nature very much, then the real value of money is better measured for some purposes in labour than in commodities.

We might as well reasonably dispute whether it is the upper or the under blade of a pair of scissors that cuts a piece of paper, as whether value is governed by demand or supply.

Producer's Surplus is a convenient name for the genus of which the rent of land is the leading species.

Though a simple book can be written on selected topics, the central doctrines of economics are not simple and cannot be made so.

Every short statement about economics is misleading (with the possible exception of my present one).