In this case it wasn't; the discussion was about legal activism and judicial review. I've read several books on the subject, some essays, and several transcript

In this case it wasn't; the discussion was about legal activism and judicial review. I've read several books on the subject, some essays, and several transcripts of supreme court cases, just because I find the subject interesting. On a more basic level, I can name the supreme court justices -- so in terms of factual knowledge, I'm quite confident I was on solid ground. My debating partner, however, didn't really have any facts at hand, but instead had strong opinions and essentially parroted oft-repeated truisms, like "the supreme court is full of ultra conservatives", a claim that certainly begs some evidence. During the argument, I made a persistent effort to back up any claims I made with examples or evidence. When my opponent said things that I thought were false, I would wait for him to finish, and tell him: "I think you're wrong because of XYZ". The first few times, it was ok, but as the argument progressed, he just got annoyed and would become irrational. For example, he would: - say he hadn't said something which he patently had said just two minutes before. In other words, a po-faced lie. - he would ask for evidence when I made a claim, and when I then provided evidence, he would say he knew it and didn't want to be bored with details, without acknowledging that it was a datapoint in favour of my position; - he would claim I was "oversimplifying", and when I would ask him how, he would refuse to tell me, saying "oh it doesn't matter". I personally really enjoy vigorous debate, and I'm quite happy to be proven wrong. Really. For two reasons: - I learn something, and learning something is cool; - I'm better prepared for the next argument! And I think to certain extent, scientists are more at ease with the idea of being proven wrong. I think we realize that it doesn't mean you're stupid; far from, you're just entertaining a theory, and if the evidence contradicts it you have no particular emotional attachment to it. Whereas I've found non-scientists to be less accustomed to having their theory shot down, and as a result they become more defensive (and hence irrational), which leads them to use what I would regard as quite underhanded and dishonourable debating tactics, a la "38 Ways To Win An Argument".