So what is needed to get us from mere theism (the belief that God exists) to Christianity?
In a word, revelation.
Last time we discussed the ability of natural theology to give us knowledge of God. We now turn to what is known as 'revealed theology,' so called because rather than coming through mere reason or observation of nature, it is given, or 'revealed' directly to us by God Himself.
For the Christian, this revelation consists in the Bible (and possibly certain utterances of the corporate Church, but we'll leave the Protestant/Catholic discussion for a later series) and the life and ministry of Jesus Christ. For the Muslim, it's the Qur'an and the prophet Muhammad. Then there's the Book of Mormon and Joseph Smith (Latter Day Saints), the Bhagavad Gita and Krishna (Hindu), the Tao Te Ching and Lao Zi (Taoism), and many, many others.
I'll cover in more detail later how we can differentiate between these various and often contradictory claims to divine knowledge, but for now let's just assume that the Christian revelation is the true one. What is it?
The Christian revelation differs from all of the others in that it is principally rooted in the life of a historical figure and the writings about that individual's life. This is decidedly not the story of a mysterious text handed down from heaven, or a vision in the sky, or some otherwise mystical experience. This is a man who lived and gained wide influence in an identifiable region of the world at a traceable time in the past. Further, this man did not claim only to have a more in-depth or complete explanation of a previous revelation, but rather made the much more extraordinary (and falsifiable) claim to be the revelation, the literal Word of God incarnate.
Without going into too much detail here, the idea is basically that if the writings about this man can be trusted to deliver his teachings to us accurately, and further if the man himself can be trusted to have spoken truthfully, then we have here a clear path to genuine knowledge of God.
And it is a much more complete and interesting knowledge than can be delivered through rational argument or even subjective experience alone. From these we can know that God is and even that He is personal and supremely powerful. But revelation tells us what He is like. From Jesus we learn that God is the very embodiment of love, that He cares deeply for us, and that He is interested in how we live.
So, yes, I think knowledge of God is definitely possible, and so this blog can now proceed with working out its various nuances. Disagree? I'd love to hear about it.