“It pays to keep an open mind, but not so open your brains fall out.”
“Keeping an open mind is a virtue—but, as the space engineer James Oberg once said, not so open that your brains fall out.”
“Do not be so open-minded that your brains fall out.”
“If you're too open-minded; your brains will fall out.”
“We want to be open-minded enough to accept radical new ideas when they occasionally come along, but we don't want to be so open-minded that our brains fall out.”