No limits whatever are placed to the productions of the earth; they may increase forever.

[P]opulation, when unchecked, goes on doubling itself every twenty-five years, or increases in a geometrical ratio. ... [T]he means of subsistence, under circumstances the most favorable to human industry, could not possibly be made to increase faster than in an arithmetical ratio.

The science of political economy is essentially practical, and applicable to the common business of human life. There are few branches of human knowledge where false views may do more harm, or just views more good.

The power of population is so superior to the power of the earth to produce subsistence for man, that premature death must in some shape or other visit the human race.

In a state therefore of great equality and virtue, where pure and simple manners prevailed, the increase of the human species would evidently be much greater than any increase that has been hitherto known.

Where there are few people, and a great quantity of fertile land, the power of the earth to afford a yearly increase of food may be compared to a great reservoir of water, supplied by a moderate stream. The faster population increases, the more help will be got to draw off the water, and consequently an increasing quantity will be taken every year. But the sooner, undoubtedly, will the reservoir be exhausted, and the streams only remain.

The histories of mankind are histories only of the higher classes.