Keeping an open mind is a virtue — but, as the space engineer James Oberg once said, not so open that your brains fall out.

By all means let's be open-minded, but not so open-minded that our brains drop out.

Do not be so open-minded that your brains fall out.

Remember, your mind is like a parachute: If it isn’t open, it doesn’t work. So keep an open mind!

I think your mind is so open your brain fell out!”10

I have learned not to think little of any one's belief, no matter how strange it may be. I have tried to keep an open mind, and it is not the ordinary things of life that could close it, but the strange things, the extraordinary things, the things that make one doubt if they be mad or sane.

An open mind, in questions that are not ultimate, is useful. But an open mind about the ultimate foundations either of Theoretical or of Practical Reason is idiocy. If a man's mind is open on these things, let his mouth at least be shut. He can say nothing to the purpose. Outside the Tao there is no ground for criticizing either the Tao or anything else.

If we keep an open mind, too much is likely to fall into it

Open your mind before your mouth

a beginner’s mind.” Remember that your mind is like a parachute — it only works when it’s open.

Open thy mind; take in what I explain and keep it there; because to understand is not to know, if thou dost not retain.

I like to consider my mind an open door. It's just not a revolving door.

A truly open mind means forcing our imaginations to conform to the evidence of reality, and not vice versa, whether or not we like the implications.

Open your mind to what I shall explain, then close around it, for it is no learning to understand what one does not retain.