Orate Door in Segovia, Spain

Doors are ambivalent. They invite and repel at the same time. Here is a quote about the ambiguity of doors.

“The man who comes back through the Door in the Wall will never be quite the same as the man who went out. He will be wiser but less sure, happier but less self-satisfied, humbler in acknowledging his ignorance yet better equipped to understand the relationship of words to things, of systematic reasoning to the unfathomable mystery which it tries, forever vainly, to comprehend”
― Huxley, Aldous. 1954. The doors of perception. London: Chatto and Windus.

Here is another quote attributed to Emerson:

Be an opener of doors to those who come after you, and don't try to make the Universe a blind alley.

The complete works of Ralph Waldo Emerson: Lectures and biographical sketches [Vol. 10]
Emerson, Ralph Waldo, 1803-1882., Emerson, Edward Waldo, 1844-1930, Page 553.