From what I've heard, this is post Hobbit, pre LotR.
"It is the mark of an educated mind to be able to entertain a thought without accepting it." - Aristotle
"Being told to be 'open minded' about something is usually a code for 'you're not going to like this, but I want to subject you to it anyway'. Conversely, being told that you are 'closed-minded' is generally a means of asserting that 'I don't like the fact that you're proving me wrong, so I will pretend that your failure to agree with my argument is a philosophical deficiency'." - RationalWiki
"Being told to be 'open minded' about something is usually a code for 'you're not going to like this, but I want to subject you to it anyway'. Conversely, being told that you are 'closed-minded' is generally a means of asserting that 'I don't like the fact that you're proving me wrong, so I will pretend that your failure to agree with my argument is a philosophical deficiency'." - RationalWiki