“The learned are said to have seeing eyes;
The unlearned have only two sores on their faces.”

Variant: They who can no longer unlearn have lost the power to learn.
Source: Aphorisms and Reflections (1901), p. 90

The Irresistible Revolution (2006)
Source: The Irresistible Revolution: Living as an Ordinary Radical

§ 7
From Lives and Opinions of the Eminent Philosophers by Diogenes Laërtius

As quoted in "The Red Gaze"' in Expressionism (2004) by Norbert Wolf, p. 92
Undated

"Fall of a City"
Selected Poems (1941)
Context: All the lessons learned, unlearned;
The young, who learned to read, now blind
Their eyes with an archaic film;
The peasant relapses to a stumbling tune
Following the donkey`s bray;
These only remember to forget. But somewhere some word presses
On the high door of a skull and in some corner
Of an irrefrangible eye
Some old man memory jumps to a child
— Spark from the days of energy.
And the child hoards it like a bitter toy.

Epilogue
Christine (1983)

Letter to Christian Northoff (1497), as translated in Collected Works of Erasmus (1974), p. 114

The Ringworld Throne (1996)

Only a Baby Small