Alan Shlemon of Stand to Reason ministries developed a great tactic to use when a Mormon or Jehovah’s Witness comes knocking on your door. It’s easy to remember, and it doesn’t require that you know much about either religion:
First, I ask them, “If you discovered you were mistaken about your faith, would you be willing to
change your religion?” This question is critical because it exposes whether or not they’re a genuine truth seeker. They are presumably there to show you’re mistaken about your faith and should change it after they show you the truth. If not, then I point out how their position is unreasonable and thank them for coming to visit. I try to avoid spending time with people who are not genuine
truth seekers and are not willing to follow the evidence where it leads. You can waste a lot of time talking to people who are closed to the truth.
Second, I ask them, “Can you offer me three objective reasons or evidences for why you believe your religion is true?” Notice this question immediately shifts the burden of proof to them, where it belongs. It takes the pressure off you and gives you valuable insight into their rationale. Remember, they’ve come to you. You’re under no obligation to jump through their hoops and answer their questions. Just be sure to keep them on track and not let them deviate from the question at hand. They’re often hard pressed to offer you convincing objective reasons. Mormons often ask you to pray and ask God to reveal the truth to you. This is not an objective reason or evidence, however, so don’t let them get away with offering it as an answer.
Alan Shlemon, “Making an Impact Without Knowing Very Much”; available from http://str.typepad.com/weblog/2007/07/making-an-impac.html; Internet; accessed 30 July 2007.