The world's population will multiply more rapidly than the available food supply.

To prevent the recurrence of misery is, alas! beyond the power of man.

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.

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

No move towards the extinction of the passion between the sexes has taken place in the five or six thousand years that the world has existed.

If I saw a glass of wine repeatedly presented to a man, and he took no notice of it, I should be apt to think that he was blind or uncivil. A juster philosophy might teach me rather to think that my eyes deceived me, and that the offer was not really what I conceived it to be.

The doctrine of population has been conspicuously absent, not because I doubt in the least its truth and vast importance, but because it forms no part of the direct problem of economics.