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

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.

The superior power of population cannot be checked without producing misery or vice.

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

The power of population is indefinitely greater than the power in the earth to produce subsistence for man.

A man is literally what he thinks.