We can only know what is true by two avenues: experience of the truth directly and believing someone else who claims to have experienced the truth (or who claims to be reporting the claims of someone else who has experienced the truth).
In our culture, we have a radical mistrust of anyone external to ourselves. Hence, we tend not to employ the latter method of knowing. In fact, we often view this way of knowing as suspect and prefer to just trust our own experiences. If we need to make sense of them, we do so for ourselves. In this way, trust is completely in the self. I must have faith in something, since all things cannot be experienced, and knowledge gained from experience must have faith in that experience and the presuppositions that guide that way of knowing. This internal only, personal experience only, oriented approach to knowledge is what I was referring to yesterday by the term liberal. Liberals are free from external authorities (hence, the term) and look to themselves as their guide. Now, this means that liberals presuppose an ability to know reality apart from any external report that is claimed to be from God. Hence, most liberals end up being pantheists, where God is imminently within, deists, where God has implanted truth in creation and within human beings, or atheists, where knowledge is in the physical universe alone (including people who are a part of that physical universe) and humans can experience that universe.
However, there are many people who would consider themselves Christian theists who are skeptical toward external authority. I have met quite a few charismatics in my life who look for direct experiences with God and ignore or demote the Bible to a lesser status in their daily life, simply because they trust their own experiences (and believe that God can be experienced directly, as I discussed before) and view them as more authoritative. There are also Christians in the mainline churches who are confused, and hold a hybrid theology, i.e., a theology gained from Scripture and experience, but trusting only their experience as authoritative (the elements of theology gained from Scripture were simply things they adopted along the way, not realizing that they did not experience those things themselves).
Within all of these views, the unified faith, the one faith, they all share is faith in the self. "Trust your heart and you'll know what to do." "Trust your instincts." "Follow your heart." These are all sayings gained from our lack of trust of the external.
But there is a major conflict between those who trust themselves and those who believe that knowledge must be gained both from personal experience and by believing a report of someone who is outside of the self. This takes real faith. Not the stuff that makes the planet crawl with seven billion philosophies of life gained from the seven billion people who, apart from others, try to make sense of themselves using their own personal experiences as the base, but real faith, the stuff of courage. Real faith denies the fearful self. It causes us to trust in another.
I argued yesterday that this faith is the only one that could possibly be true. Faith in an external claim, a report, is needed to know metaphysical reality. The atheist, then, cannot know. The liberal cannot know. But this lack of metaphysical knowledge doesn't simply make them agnostics in terms of the spiritual, but in terms of the physical world as well, since a metaphysical knowledge is needed in order to employ a naturalistic methodology in the effort to gain knowledge.
This is where those who believe in the Bible have an upper hand in being courageous to trust what is external to them. This doesn't mean that they experience the Bible externally. We experience the language of the Bible subjectively, as all language is subjective; but we do not necessarily experience everything the Bible teaches. I was not there when Christ rose from the dead. I do not know the attributes of God or the spiritual standing of mankind toward God without the external claims of the Bible. But apprehension of knowledge and comprehension of knowledge are two completely different animals, and those who provide an apologetic for their fear, so they need not exercise faith in an external report, often conveniently confuse them. The whole world is experienced subjectively, but we do not then say we can no nothing of the whole world because we apprehend knowledge subjectively (for that would be something we knew to be true and we're back to self refuting claims again).
But we need to make the important distinction that although knowledge is related to us subjectively, it can be known sufficiently enough to comprehend, even if knowledge is not exhaustively known. The knowledge the Bible communicates, guided by the Holy Spirit within the person and the community as a whole, reaches our minds through subjective language. As Michael Horton says in his The Christian Faith, "the relativity of our perspective does not entail the relativism of what is known" (p. 204). This confusion between the two is one of the biggest blunders of our society, and it has kept us believing that, since we apprehend knowledge subjectively, we cannot gain any more reliable information from external knowledge than from ourselves. Hence, why trust others? I can only trust myself, follow my own heart.
Notice the exaltation of the human in this scheme. It reminds me of the heretics in Second Peter, who emphasize the viewpoint and abilities of humans over the viewpoint and ability of God. They argue that man is hopelessly finite and sinful, and therefore, cannot overcome sin. The letter counters by saying that God has given us everything we need for life and godliness, and in fact, we partake of His divine power to overcome sin in our lives. They further argue that Christ's return must be spiritual or a myth, since He has not yet returned. The response is that a thousand years is like a day in the perspective of God. But what is even more important for what we are discussing here is that the heretics also argue that the Scriptures are just the experiences of humans and there is no way to know what God has said and what humans have said. The response, of course, is that no prophecy (Second Peter's word in context for revelation found in the Scripture, as opposed to what some argue) is a product of the human mind, but men moved by the Holy Spirit wrote. Notice that men wrote and were moved by the Spirit, not taken over by Him. That's because the language they used (and all of the things that make up that language) is their own subjective form of communication. Yet, the determining factor Second Peter would have us emphasize is God's ability to communicate accurately through that subjective language. The Spirit who guided the prophets to write Scripture also guides the Church and the individual within the Church to understand and appropriate it. The Bible, therefore, would have us emphasize God's ability to communicate these truths above our lack of ability to understand them.
Hence faith, true biblical faith, comes by hearing and hearing through the word of Christ. We must first place our trust in God's abilities over our own. We are called to the truth of the gospel that is beyond our own experience, and only becomes our own experience once we've entered the story through faith in that report. We are called to submit ourselves to the Lordship of Christ and that this means we subject what we would make of our personal experiences to the teachings of Scripture, an external authority. We do so because the Scripture subjectively communicates reality to us. It communicates the reality of our spiritual condition, the reality of God's nature, the reality of our future judgment, the reality of our inability to know reality correctly apart from it.
It is self refuting to trust in personal experience for spiritual truths alone if one has made the what can be known versus what is just speculation, i.e., faith dichotomy. If there is no external report, then we truly cannot know anything. But if God has spoken in Scripture, then we can know sufficiently what we need to know about so many things (as well as many things we don't by way of necessity need to know). Knowledge is possible for us because God is at work communicating to us through the external report. We can believe it or choose not to do so, but it is not the Christian who is limited by his subjective nature, and it is not, therefore, the Christian whose faith is based on fear and uncertainty, but true knowledge and hope.
And He came and preached peace to you who were far away, and peace to those who were near; for through Him we both have our access in one Spirit to the Father. So then you are no longer strangers and aliens, but you are fellow citizens with the saints, and are of God's household, having been built upon the foundation of the apostles and prophets, Christ Jesus Himself being the corner [stone].