Oliver Wendell Holmes (1809–1894) Poet, essayist, physician
The Autocrat of the Breakfast Table (1858)
Often given as: A mind that is stretched by a new experience can never go back to its old dimensions. <br class="br">Or: A mind that is stretched by a new idea can never go back to its old dimensions. <br class="br">Actually by Oliver Wendell Holmes, Senior, from " Autocrat of the Breakfast Table https://books.google.com/books?id=BoQ3AQAAMAAJ&pg=PA502&dq=%22stretched+by+a+new+idea%22&hl=en&sa=X&ved=0ahUKEwidspn60tTJAhVJ1GMKHbt3Bn0Q6AEIHTAA#v=onepage&q=%22stretched%20by%20a%20new%20idea%22&f=false", originally published in The Atlantic, September 1858. <br class="br">Misattributed
Oliver Wendell Holmes (1809–1894) Poet, essayist, physician
The Autocrat of the Breakfast Table (1858)
“A man's mind stretched to a new idea never goes back to its original dimensions.”
Oliver Wendell Holmes Jr. (1841–1935) United States Supreme Court justice
Also reported as "One's mind" instead of "A man's mind", and "can never go back" or "never regains" instead of "never goes back"; most likely properly attributed to Oliver Wendell Holmes, Sr.
Misattributed
“The mind, once stretched by a new idea, never returns to its original dimensions.”
Ralph Waldo Emerson (1803–1882) American philosopher, essayist, and poet
“The mind, once stretched by an idea, never returns to its original dimension.”
Ben Carson (1951) 17th and current United States Secretary of Housing and Urban Development; American neurosurgeon
Source: Think Big (1996), p. 224
“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
`Abdu'l-Bahá (1844–1921) Son of Bahá'u'lláh and leader of the Bahá'í Faith
"The True Modernism" http://reference.bahai.org/en/t/c/FWU/fwu-1.html <br class="br">Foundations of World Unity <br class="br">Context: Humanity has emerged from its former degrees of limitation and preliminary training. Man must now become imbued with new virtues and powers, new moralities, new capacities. New bounties, bestowals and perfections are awaiting and already descending upon him.
Adam Smith book The Theory of Moral Sentiments
Section II, Chap. I.
The Theory of Moral Sentiments (1759), Part VI