However, there are people who don't experience as much, if any, attachment or identification with "their own ideas", and instead view "debate" (or indeed, any sort of exploration of ideas, truth, and so forth) as a chance to be, to use an over-used phrase, "less wrong". It doesn't bother me if someone demonstrates to me that what I thought is wrong (as long as they do it in a way that respects me as a person), and in fact I welcome the correction (though sometimes it may be difficult to process if it is a long-held idea with wide consequences).
As usual, there's a spectrum (or two) here: a spectrum of identifying with your own ideas, and a spectrum of levels of personal respect when "debating". Certainly a very bad combination is one person with a high level of self-identification with their own ideas being debated/attack by someone who (a) has no concept that this self-identification experience is real (b) cannot engage with the ideas without criticizing the other person.
1. Co-founder who clearly signals respect and self-reflection, and who much later reveals they have a penchant for the occasional debate and dis-attachment from their own ideas.
2. A co-founder who signals they like debates in a candidate meeting.
I rankly speculate here on HN that if OP always avoids #2, not only will nothing bad happen as a result, but they will also decrease the chance of choosing a bad candidate.
I further rankly speculate this for any founder.
HN debates are fun, but they hide the fact that debate is a low-effort tool. Like drinking alcohol, it can be useful. But if it moves from being a mere implementation detail to becoming part of the API in a candidate meeting: run!
I know some people are energized by debate, but I'd rather work with someone who builds my confidence rather than constantly attacks my ideas and, if those don't have any weak corners, my character and judgement. Nothing wrong with either preference, but the two shouldn't work together in my experience.