To him who has had the experience, no explanation is necessary. To him who has not, none is possible.
Education is the progressive discovery of our own ignorance.
Every man who rises above the common level has received two educations: the first from his teachers; the second, more personal and important, from himself.
For man, the unexamined life is not worth living.
One only sees what one looks for, one only looks for what one knows.
This alone I know, that I know nothing.