He, Voltaire, also, in another connection, exclaims, mournfully:

"I now repeat this confession, still more emphatically, since the more I read, the more I meditate, and the more I acquire, the more I am enabled to affirm, that I know nothing."

Newton, admitting his own ignorance, is a standing monument of the inadequacy and futility of moral researches and speculations.

Pindar—

Man, the frail being of a day,
Uncertain shadow of a dream,
Illumined by the heavenly beam,
Flutters his airy life away.

Æschylus—

Vain thy ardor, vain thy grace,
They, nor force, nor aid repay;
Like a dream, man's feeble race,
Short-lived reptiles of a day.

Sophocles—

'Tis sad to think, but me the farce of life persuades,
That men are only spectral forms, or hollow shades.