Crazy Enough For You?

It seems that I have had this experience before:

I am talking to an eminent, senior scientist in my field, and the conversation will be about semi-normal sciencey things and then -- zoom! without warning! -- we are in the realm of big-idea crazy-talk, as in really crazy.

Sort of like this, with the speaker being the eminent scientist:

"And then when we were studying X, it led to the insight that ... and of course that was different from what Schmoe found, but when we also tried Z, we found that results were consistent. But of course, the Earth is flat, and we are taking that into account, but Schmoe didn't."

I had such a conversation recently, and it also involved something like this:

"I read your paper on ABC, but I think you are basing a lot of your work on the assumption that the Earth is round, but it isn't of course. There's no evidence for that. You are making the same mistake that everyone makes. I used to, but then I realized: The Earth is flat."

I realize that someone doesn't have to be eminent (or old) to be (apparently) crazy, but I mention it because I wonder if it affects how we respond to this type of thing. That is, if someone you don't know wanders into your office with a New Theory of Everything, would your response be different compared to what you might say (and how you would say it) if someone with a long and distinguished record of scientific accomplishment (apparently) starts to go off the rails with their scientific ideas?

Are we more likely to assume that the former is insane (and not an eccentric genius who wanders from campus to campus trying to get someone to discuss their brilliant, transformative idea), and that the latter just might be on to something that has been hidden to the scientific masses because we so love conformity and are afraid to step back and blast away at centuries of belief in something we all "know" to be true?

I am not talking about level of respect -- I hope we would all be respectful to the maybe-crazy person with the New Theory of Everything, even if it is written in tiny letters covering the sides of grocery bags -- but about how likely we are to say "You're wrong" or to wonder if maybe we have been blind to the Truth all these years because we are science-sheep.

Perhaps it matters how (apparently) crazy the idea is. "The world is flat" is a good analogy for the encounter I had recently, but there are more subtle versions of (possibly) crazy ideas.

In my most recent encounter, I did not directly say "You are wrong". I said "There's actually a lot of evidence that the world is round. For example... [devastating list of compelling evidence]", but all I got back in response was "Well, I was talking to Other Famous Guy about this and he agreed with me."

Conversation = over for me at that point.

It was even pointless (and weird) to have to summon evidence for how we know the Earth is round -- and that's why I think I only did so because of the eminence of the scientist with whom I was having the conversation. But I rather quickly reached my limit of being willing to discuss this. At that point, the best options are to change the subject or leave, depending on what is possible for the situation.

Have any of you had this experience? What did do you? Did you doubt for a moment your belief in whatever idea was being challenged? If you tried to discuss the issues, did you make any headway?