Knowledge is our most powerful engine of production.

Material goods consist of useful material things, and of all rights to hold, or use, or derive benefits from material things, or to receive them at a future time.

The commercial storm leaves its path strewn with ruin. When it is over there is calm, but a dull, heavy calm.

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.

All wealth consists of desirable things; that is, things which satisfy human wants directly or indirectly: but not all desirable things are reckoned as wealth.

Consumption may be regarded as negative production.

It is common to distinguish necessaries, comforts, and luxuries; the first class including all things required to meet wants which must be satisfied, while the latter consist of things that meet wants of a less urgent character.