"It is an acknowledged truth in philosophy that a just theory will always be confirmed by experiment."

“THERE is scarcely any inquiry more curious, or, from its importance, more worthy of attention, than that which traces the causes which practically check the progress of wealth in different countries, and stop it, or make it proceed very slowly, while the power of production remains comparatively undiminished, or at least would furnish the means of a great and abundant increase of produce and population.”

“Surely then some distinction between the different kinds of labour, with reference to their different effects on national wealth, must be admitted to be not only useful, but necessary; and if so, the question is what this distinction should be, and where the line between the different kinds of labour should be drawn.”

“I know of no well-directed attempts of this kind, except in the ancient family of the Bickerstaffs, who are said to have been very successful in whitening the skins and increasing the height of their race by prudent marriages, particularly by that very judicious cross with Maud, the milk- maid, by which some capital defects in the constitutions of the family were corrected.”

“It is also very important to observe, that menial servants are absolutely necessary to make the resources of the higher and middle classes of society efficient in the demand for material products.”

“The main peculiarity which distinguishes man from other animals, is the means of his support, is the power which he possesses of very greatly increasing these means.”

“A feather will weigh down a scale when there is nothing in the opposite one.”