This is going to be thankfully short. Spotted in the comments section of the RationalWiki blog:
I challenge you to accept this criticism with an open mind.
This came at the end of an exceptionally non-specific derp-fest about how climatology is a pseudoscience. So non-specific, in fact, that it was one of those things that is pointless to refute. But this ending stood out for the following reasons.
An open mind is one that entertains an idea, assesses it, and then decides to accept or reject it. A closed mind either rejects the idea a priori, or accepts it blindly.
Because a period of assessment is involved in having an open mind, acceptance or rejection are equally possible (although not necessarily equally probable, unless you need to start with a uniform prior). No one can be dared to accept something “with an open mind”. That’s impossible. If the desired result is known in advance, if acceptance (or rejection) is demanded beforehand, then there can be no open-mindedness involved.
Open-mindedness demands only one simple thing; that you entertain both acceptance and rejection of an idea are possible before you start assessing it. That’s all. Your answer must stand up against the possibility of its opposite. Acceptance should be shown to be more worthy against rejection, or rejection needs to be shown to be more worthy next to acceptance. If you cannot do this, then what good is your actual answer? If it was impossible to come away from something thinking “no”, then did you really choose “yes” with a free and open mind?