How can we know about God if there is a God to be known? In my experience as a minister, I would say that most people, if they speak of God, speak of God in terms of their experience. They will tell a story about God's presence at a particular moment in their lives or they will speak of situations in which God's presence is particularly evident for them. The experience and the name for this experience will vary with the person. It will vary given the language and rituals they have developed for naming this experience.
I am finding enjoyment listening to AM radio as I drive back and forth to the church and to various places in East Tennessee. I listen to the various religious broadcasts. This is educational for me. I hear gospel music mixed with prayers by local preachers and musicians. Sometimes the prayers will be spoken all at once, a cacophony of prayer. Sometimes one person will pray at length. "The Lord" and "Jesus" are the most common names used in prayer. I find these radio shows quite interesting. There is real care expressed for their listeners who are often named. Each is prayed for in some manner. Both preachers, pray-ers and listeners who call in will speak about what "The Lord" has done in personal terms.
While people may talk about other sources for information about God (such as the Bible), I find that when it comes right down to it, people will claim knowledge of God by the authority of their own experience. The punchline of the evangelical hymn, "He Lives" is this: "You ask me how I know He lives? He lives within my heart."
Personal experience is the way non-traditional Christians or progressive Christians approach God as well. They may not use the term God preferring the Sacred or the Divine or something else. They may use the Bible and often many other sources for inspiration. But as with almost everyone I have met, the authority of personal experience is the bottom line for "knowing" God. That is, of course, for those who are confident of the presence of God. I should also say that there are people who affirm the existence of God without referring to personal experience.
Whether or not these experiences of the Sacred or of God are experiences with something real or are conversations with themselves, I cannot say. For those who put great trust in their experiences, God certainly appears real to them.
Here is a quiz for you. What is Your Spiritual Type?