http://www.human.toyogakuen-u.ac.jp/~acmuller/contao/laotzu.htm

There is nothing better than to know that you don't know.
Not knowing, yet thinking you know--
This is sickness.
Only when you are sick of being sick
Can you be cured.
The sage's not being sick
Is because she is sick of sickness.
Therefore she is not sick.

Who recognizes his limitations is healthy;
Who ignores his limitations is sick.
The sage recognizes this sickness as a limitation.
And so becomes immune.

Who knows what he knows is healthy;
Who ignores what he ignores is sick;
Who grows sick of sickness recovers;
The sage is never sick, always sick of sickness.

To know unconsciously is best.
To presume to know what you don't is sick.
Only by recognizing the sickness of sickness
is it possible not to be sick.
The sages' freedom from ills
was from recognizing the sickness of sickness,
so they didn't suffer from sickness.

Knowing ignorance is strength.
Ignoring knowledge is sickness.
If one is sick of sickness, then one is not sick.
The sage is not sick because he is sick of sickness.
Therefore he is not sick.