The most baleful mischiefs may be expected from the unmanly conduct of not daring to face truth because it is unpleasing.

No state has hitherto existed (at least that we have any account of) ... that no check whatever has existed to early marriages, among the lower classes, from a fear of not providing well for their families, or among the higher classes, from a fear of lowering their condition in life.

Nature herself in times of great poverty or bad climatic conditions, as well as poor harvest, intervenes to restrict the increase of population of certain countries or races; this, to be sure, by a method as wise as it is ruthless.

A writer may tell me that he thinks man will ultimately become an ostrich. I cannot properly contradict him.

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.

The main peculiarity which distinguishes man from other animals is the means of his support - 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.