1) We are all raised as believers. As children we believed whatever our parents told us, all of us.
2) We were raised in our respective families and cultures to believe what our parents told us about religion.
4) Psychological studies have shown that most of us, most of the time, look for that which confirms what we believe rather than that which disconfirms it, even though the latter is the best way to get at the truth. This is known as Confirmation Bias.
5) Neurological studies have shown that people have a sense of certainty about the beliefs they have that is unrelated to the strength of the actual evidence, as Robert Burton argues in On Being Certain: Believing You Are Right Even When You're Not
6) Skepticism is not usually an inherited characteristic. We must acquire the capacity to doubt what we are raised to believe. Skepticism is the adult attitude.
Full stop. There are a lot of books on these subjects. This data is undeniable, noncontroversial and obvious. We must think about the implications of what these undeniable facts tell us about who we are as human beings. If we were raised as Christians then we seek to confirm what we were raised to believe because we prefer that which we were raised to believe. If we were raised as Muslims then we seek to confirm what we were raised to believe because we prefer that which we were raised to believe. If we were raised as Orthodox Jews then we seek to confirm what we were raised to believe because we prefer that which we were raised to believe. If we were raised as Scientologists then we seek to confirm what we were raised to believe because we prefer that which we were raised to believe. If we were raised as Hindu's then we seek to confirm what we were raised to believe because we prefer that which we were raised to believe.
7) When there are billions of people who are certain of an inherited faith they all learned in the same manner, who live in separate geographical locations around the globe, who all prefer to believe what they were raised to believe, and who all seek to confirm that which they were raised to believe, it should cause them to doubt what they were raised to believe. What is there not to understand about this?
8) It will not do to argue against atheists that this data applies to us too. This is a fallacious argument that cannot be used to sidestep the implications for one's own inherited religious faith. All believers who are certain of their faith will use this same fallacious argument against atheists. But doing so does nothing to solve the problem of religious diversity, since they still have not come up with a method that can solve their own differences. Atheists are doubters. We are skeptics. Knowing this data causes us to require hard, cold evidence for that which we can accept. We have concluded this requirement is never met by any religious faith.
9) Skepticism is a filter that adults use to help us sift out the wheat of truth from the chaff of falsehood. We cannot doubt that filter! There is no other alternative.
10) The Outsider Test for Faith is the best and only way to get at the truth if you want to know the truth. Examine your own faith with the same level of skepticism you use when examining the other religious faiths you reject. We cannot have a milquetoast test when it comes to the truth. We cannot merely say to people that they should be skeptical without offering a standard of skepticism. Why? Because if we ask believers who are certain of their faith to test it with doubt then to a person they will say they have, and that their faith is sure. But ask them to test their faith with the same level of skepticism they use when examining the other religious faiths they reject and that will get their attention. I have their attention now.
If anyone thinks the Outsider Test for Faith is unfair or faulty in any way then propose a better alternative. What is the alternative?