This good answer ended up with a lot of comments about whether the phrase is "close-minded" or "closed-minded." Since this debate seems to have reasonable arguments on both sides, I thought a new question would be prudent.
Personally, I think it is close-minded, the opposite of open-minded, and that both of these (open and close) use the intransitive forms of these verbs. In another words, I think the mind opens or the mind closes, as opposed to the mind being opened or closed.
But I thought the comments raised some interesting points about the word formation, and I may have to reconsider my opinion.
Is it "close-minded" or "closed-minded"?
EDIT:
The NGrams are nice to demonstrate usage, but what I would like to know is more along the lines of why rather than which.
Best Answer
Close-minded was first, but closed-minded is dominant:
Here's the earliest close-minded reference I can find from a Narrative of a Journey in the Interior of China, by Clarke Abel, 1818:
I found closed minded back to 1913 in The Century Magazine:
Edit:
After considering @FumbleFingers' comments here and his subsequent answer, I have to agree that most of the earlier close-minded references found through Google Books (including the one above) are using close |kloʊs| in this sense (from NOAD):
This is also proven by this definition of uncommunicative from John Craig's A New Universal Etymological Technological, and Pronouncing Dictionary of the English Language, 1859:
It seems the phrase was once a common description for someone who "kept their own counsel"—usually used as a derogative, but sometimes as a compliment.
However, I did find this earlier use of close-minded specifically to mean the opposite of open-minded from an 1898 issue of The Outlook:
I also found evidence of a shift towards this sense of close-minded in other writings by the early 1900s. So, to conclude, I think the only thing new about the confusion evident by the 1960s was the frequency of the two terms in print. I realize this may not ultimately answer the question, which is correct, but the timeline seems significant to me.