Demand and supply are the opposite extremes of the beam, whence depend the scales of dearness and cheapness; the price is the point of equilibrium, w… - Jean-Baptiste Say

Political economy has only become a science since it has been confined to the results of inductive investigation.

The haggardness of poverty is everywhere seen contrasted with the sleekness of wealth, the exhorted labour of some compensating for the idleness of others, wretched hovels by the side of stately colonnades, the rags of indigence blended with the ensigns of opulence; in a word, the most useless profusion in the midst of the most urgent wants.

Wherefore it is impossible to succeed in comparing wealth of different eras or different nations. This, in political economy, like squaring the circle in mathematics, is impracticable, for want of a common mean or measure to go by.