“It was only a matter of being willing to believe in a Power greater than myself.” (Page 12, Big Book)
Belief flows from credibility.
If reason, evidence, or authority tells me something is the case, I believe it to be the case. In other words, belief depends on credibility. The credibility of a proposition depends entirely on matters beyond the will. I cannot will reason to support a proposition, I cannot will evidence to come into existence, I cannot will someone to have authority. It obviously makes no sense as it stands. I cannot will belief, and I cannot will unbelief. If reason, evidence, or authority do not convince me, I cannot override that with will. What does it mean to say, ‘willing to believe’, therefore?
The proper object of will is action. I can therefore will action.
To will action in this context means to will action that takes me from no belief to some belief or some belief to better or full belief.
To be willing to believe means to take actions along a certain line, which, if taken and successful, will produce belief.
What at the actions? The Twelve Steps, which involve learning from authority, exercising reason, and gathering evidence.
The minimal belief required is that the Twelve Steps may work for me.