The things I know, every man can know, but, oh, my heart is mine alone!

Knowing is not enough; we must apply. Willing is not enough; we must do.

Those who know nothing of foreign languages know nothing of their own.

He who cannot draw on three thousand years is living from hand to mouth.

I am not omniscient, but I know a lot.

O glücklich, wer noch hoffen kann,aus diesem Meer des Irrtums aufzutauchen!Was man nicht weiß, das eben brauchte man,und was man weiß, kann man nicht brauchen.

Eigentlich weiß man nur wenn man wenig weiß - mit dem Wissen wächst der Zweifel.

Mediocrity has no greater consolation than in the thought that genius is not immortal.

What is not fully understood is not possessed.