Asking who makes it possible for us to believe is the wrong question in my opinion. I return to your quote from the Quaker, Margarette Fell. Fox expressed the opinion that you had to 'say' the words not hear them said or have some one tell you they were said. You had to 'have' or 'be' the light. This is not the same as believing because you see someone else has the light. Good for them. But if you do not have it yourself you are a thief taking the word from others. "we have taken the scriptures in words, and know nothing of them in ourselves." I suppose an optimist would suggest you spend time and effort finding the light in yourself. "Christ's light ... God's presence within a person, ... a direct and personal experience of God". I can study the subject but I am much too cynical to believe.