The moon is not kept in her orbit round the earth, nor the earth in her orbit round the sun, by a force that varies merely in the inverse ratio of the squares of the distances.

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

The ordeal of virtue is to resist all temptation to evil.

Evil exists in the world not to create despair but activity.

The moon is not kept in her orbit round the earth, nor the earth in her orbit round the sun, by a force that varies merely in the inverse ratio of the squares of the distances.

Population trends have always provoked doom-fraught oracles, because their popular interpreters suppose that every new series will be infinitely sustained; yet, beyond the short term, expectations based on them are never fulfilled.

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