Believe it or not, this isn’t from AA. It was devised as a means to persuade non-believers to accept Christianity.
In 1954, the Reverend Samuel M. Shoemaker wrote a story about an unfortunate who came to him admitting that he didn't believe in God and certainly didn't know how to pray. Shoemaker asked him to "try an experiment," as he had nothing to lose. He asked him to get down on his knees and say anything at all that came to his mind, addressing his thoughts to "The Unknown." He then asked if the man could read just one chapter from the Bible, from the book of John. Solely out of respect for Shoemaker, the man obliged, but fighting every step of the way. This went on for some time, until one day the man actually began praying to God and reading the Bible and other works on his own. The man eventually became a spiritual leader within his church. Shoemaker believed that this was possible because the man "acted as if he had faith" until faith came by accident, or "until there was an opening for God to come through."
The slogan "act as if" has been used in AA circles ever since.
Is it just me, or does it seem as if many of them never really quite move past the "acting as if" or "faking it" part?
A Ghost In The Closet: Is There An Alcoholic Hiding?, Dale Mitchell, Page 194.
Secondary source: orange-papers.info