Beware of false knowledge; it is more dangerous than ignorance.

Knowledge is dangerous.

The one thing that is more dangerous than true ignorance is the illusion of understanding.

Risk comes from not knowing what

It is more important to know that you don't know, than to know what you know.

My ignorance wasn’t just annoying. It was dangerous.

It is what you do not know that is your greatest risk.

The saying that a little knowledge is a dangerous thing is, to my mind, a very dangerous adage. If knowledge is real and genuine, I do not believe that it is other than a very valuable possession, however infinitesimal its quantity may be. Indeed, if a little knowledge is dangerous, where is the man who has so much as to be out of danger?

Since knowledge is but sorrow's spy,
It is not safe to know.

Far more crucial than what we know or do not know is what we do not want to know.

We are sickened by the unknown, but knowledge can prove poisonous.

It is always important in matters of high politics to know what you do not know. Those who think they know, but are mistaken, and act upon their mistakes, are the most dangerous people to have in charge.

[A] theory is a very dangerous thing to have.

What we don't know as a nation and as a citizen can kill us.