Nothing in the world is more dangerous than a sincere ignorance and conscientious stupidity.

Nothing in the world is more dangerous than a sincere ignorance and conscientious stupidity.

Who ne'er knew salt, or heard the billows roar.

Who ne'er knew salt, or heard the billows roar.

Real knowledge is to know the extent of one's ignorance.

Real knowledge is to know the extent of one's ignorance.

The learned man knows that he is ignorant.

The learned man knows that he is ignorant.

Gross ignorance is 144 times worse than ordinary ignorance.

Gross ignorance is 144 times worse than ordinary ignorance.

If I don't have wisdom, I can teach you only ignorance.

If I don't have wisdom, I can teach you only ignorance.

I do not pretend to know where many ignorant men are sure -- that is all that agnosticism means.

I do not pretend to know where many ignorant men are sure -- that is all that agnosticism means.

By ignorance we mistake, and by mistakes we learn

By ignorance we mistake, and by mistakes we learn

There is no reply to the ignorant like keeping silence

There is no reply to the ignorant like keeping silence