“The mind that opens to a new idea, Never comes back to its original size.”
Albert Einstein (1879–1955) German-born physicist and founder of the theory of relativity
Actually said by Oliver Wendell Holmes, Sr. in his book The Autocrat of the Breakfast Table: "Every now and then a man's mind is stretched by a new idea or sensation, and never shrinks back to its former dimensions."
Misattributed