We are not quite sure of any one thing in biology; our knowledge of geology is
relatively very slight, and the economic laws of society are uncertain to
every one except some individual who attempts to set them forth; but before
the world was fashioned the square on the hypotenuse was equal to the sum of
the squares on the other two sides of a right triangle, and it will be so
after this world is dead; and the inhabitant of Mars, if one exists, probably
knows its truth as we know it.