To prevent the recurrence of misery is, alas! beyond the power of man. - Thomas Robert Malthus

The first business of philosophy is to account for things as they are; and till our theories will do this, they ought not to be the ground of any practical conclusion.

A feather will weigh down a scale when there is nothing in the opposite one.

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.