Technique: Establish source credibility. You must appear likeable, authoritative, trustworthy or expert. If you're not, then reference someone who is. A guest expert (You can always find one to say virtually anything you like) or better yet, for those of us without our own talk show or column, simply reference a program…"an article in the NY Times" or "the Washington post said…"A special on the Discovery channel the other day showed that…." Or "I read in Scientific American that…". If you know the facts won't be checked then use this method at will. If someone calls your bluff and asks which article, edition, issue or show, then say, "I'm not sure off the top of my head. Let me look for it and I will get back to you." Of course you never do get back to them unless the reference was legit. If the person continues to press for documentation (which will very, very rarely happen), then simply say you couldn't find it. Of course you cannot continue using this method if they keep calling your bluff. If you have 2 strikes, stop before you get the third. An excellent strategy to follow if you argue with the same person or group of people on a regular basis (for example, at work) is this. Provoke them into requiring sources of your information. For the first two or three times, make sure you have a legitimate source and provide it to them. Each time, make a point of your invulnerable integrity. After the third time, however, say, "Listen, I've provided you with legitimate sources time and again. If you think I'm going to keep doing all that work every time your ignorance shines through, your crazy. Look it up for yourself." Or something like that, then go to town with impunity.