Here's an interesting two-part experiment. It can be conducted by anyone at all, regardless of religious persuasion or lack thereof.
Part 1: Choose a Muslim neighbor, friend or colleague, and ask three simple questions. Although the answer to the first question might appear obvious, ask it anyway, "Are you a Christian?" Without hesitation she will reply she is not a Christian but a Muslim.
Question number two: "Christians believe that Jesus is God and died on the cross for our sins, so I assume you don't believe that. Is that correct?" Again without embarrassment she will inform you she does not believe Jesus is God, nor did he die on the cross for our sins.
Now the final question: "Could you give me a few reasons you don't believe that?" She won't have to think a minute before giving them. They will probably include the fact that Islam does not believe Allah can be associated with any created being, no individual can bear the sins of another, and the Quran says that Jesus did not die.
Now it's time for part 2. Ask a non-Muslim the same questions but with a slight twist, "Are you a Muslim?" When he says that he is not, continue with, "Muslims believe that Muhammad was a Prophet from God, so I guess you are saying you do not believe he was a Prophet. Is that right?"
Chances are you will already sense some discomfort, some hesitation in the reply. Your interlocutor might explain that he is an agnostic, that he knows Muslims believe Muhammad is a Prophet, or that he's not really sure. If he does agree that he does not believe Muhammad to be a Prophet, proceed with question number three.
"Could you give me a few reasons why you don't believe Muhammad was a Prophet of God?" I doubt if one American in a hundred could give an intelligent, cohesive reply.
If you do carry out this experiment, I'd love to learn the results. Leave a comment or send me an email.
PS - There are variations to the experiment. For example, ask the Jewish professor of religious studies at your local university (or any Jewish friend) if she is a Christian. When she replies she is not, confirm it is correct that she does not believe Jesus was God and learn her reasons. Then ask her if she is a Muslim. Again when she replies she is not, confirm it is correct she does not believe Muhammad was a Prophet of God, and again inquire about her reasons. The purpose of the experiment would be to see if she was as forthright in her second response as she was in her first.