I think this is the spot where your logic stopped working.
The idea is that you don't care whether they agree. You'll listen to opposing arguments, of course, but the goal isn't to get them to agree. They're asking you because they're interested.
Or at least, that's how it should work. It stops working when it becomes an interview question.
The point is to see whether someone thinks originally. If you have opinions you're reluctant to share among peers without wording it carefully, and you've spent a lot of time thinking very carefully about the topic, then there's a pretty good chance you're an interesting person to know.
EDIT: Another way to phrase it: If you give an answer that you truly believe and that you've thought carefully about for a long time, and they disagree loudly and immediately, then there are two possibilities: Either they have given the topic more thought than you (which is entirely possible), or they are less open-minded than they think they are. Both outcomes give useful information to you.
Though we won't be able to make good on the bet, I would confidently wager a supermajority of people who fit that criteria are not particularly interesting to you, or any given individual for that matter.
In my experience, most people who spend a long time thinking about their controversial beliefs aren't especially insightful or interesting to those who disagree with them. For low hanging fruit we can just look at politics. But even beyond that, the universe of controversial ideas is so vast that it's unlikely a person's given muse will be compelling or insightful to other people.
Original thinking tends to be offensive. If you're right, you often can't go around saying you're right. You have to keep your thoughts to yourself. And if you have a scientific mind, you want to seek truths wherever they are.
If you get in the habit of actively trying to seek out radioactive truths, you'll stumble on some interesting ideas eventually. And I'd love to know anyone who genuinely makes it a habit (as opposed to doing it for social signaling).
You're right that the majority of people wouldn't be interested, because most people have deeply-held beliefs. Getting at original ideas requires a fluidity that often runs against natural instincts.
Believing in the theory of evolution would have placed you firmly outside the Overton window, at the time.
If they were seeking after political Truth, they found it in one or another of the hundred political gospels which govern men on earth; if they were seeking after the Only True Religion, they found it in one or another of the three thousand that are on the market. In any case, when they found the Truth, they sought no further; but from that day forth, with their soldering-iron in one hand and their bludgeon in the other, they tinkered its leaks, and argued with objectors."
That's why it's important to have a criteria ahead of time.
If I were asking the question, I would look/ask for: * A non-trivial heretical view (think OO/FP, unit testing, etc., not some obscure language operator) * A set of arguments to justify the heretical belief * A set of objections to their heretical belief * Counter-arguments to those objections * Evidence-based and logical reasoning to the above * Openness to counter-argument, willingness to debate the issue
I don't think it's a very good question to surprise someone with.