It is not from the benevolence of the butcher, the brewer, or the baker that we expect our dinner, but from their regard to their own interest.

The real and effectual discipline which is exercised over a workman is that of his customers. It is the fear of losing their employment which restrains his frauds and corrects his negligence.

The propensity to truck, barter and exchange one thing for another is common to all men, and to be found in no other race of animals.

All money is a matter of belief.

Science is the great antidote to the poison of enthusiasm and superstition.