One of my seminary professors once said in class that today's basic problem swirls around epistemology. Epistemology is the study of how we know what we know. He was right!
In the pre-Enlightenment era, the Western world sought universal truth. Plato taught the "real" world was the metaphysical world of which the physical world was a copy. In some ideal realm there was a real chair of which all physical chairs were but copies. Aristotle argued that the real world was knowable through the senses. Neither Aristotle nor Plato would dismiss revelation as a way of knowing. The gods did, on occasion, speak. Scholastics and Renaissance churchmen took up the arguments and continued them but the latter said humans were capable of knowing. Enlightenment philosophes said not only were human beings capable, they could know truth and reality because it was coherent. What was true was consistent with the testimony of the senses and the application of the scientific method.
Alexander Campbell, who Ernst Lee Tuveson said was the first to link Enlightenment thought to historic Christianity made sharp distinctions between fact, faith, and opinion. Fact was what was reality known by one's own senses. Faith was the belief of testimony. Opinion was what you believed without the evidence of sensory experience or testimony. According to Campbell, I know my office chair is real because I am sitting in it. That's a fact! I believe George Washington is buried at Mount Vernon because of the testimony of others (I can't see inside the tomb so I don't know it as a fact). I am of the opinion that God has made the worlds for man to explore (Scripture doesn't say that). Campbell would argue that the Scripture is God's Word to man given by revelation as a testimony to His person and work. He would not deny it was written in a context, but Campbell would say it was written for a purpose.
Today knowledge is either the perception of the individual or developed in community. It is always incomplete and absolute knowledge is impossible. There is enough truth in those statements to make them sound plausible.
As a historian, I have long been familiar with the "historian's dilemma." The dilemma is that if I seek an understanding of space-time events, I must do so through the investigation and interpretation of original documents. These documents may be written testimony of contemporaries, they may be government or church documents and records, they might be bills of sale, trade agreements, and a broad assortment of other materials. If I study the written testimony of those contemporary to the event, I must make allowances for the biases of the authors. Then, too, I must make allowances for my own biases and prejudices. The question is, can I ever know enough to say I know the exact nature of the event being studied? The answer is, No! There is always room for a variation of views. Could I, however, know something about the event? Yes!
Human knowledge on this side of glory is always incomplete and partial, but is it sufficient? Scientists tell us the "laws of nature" are not always as constant as we once thought but they are sufficient for practical use. Every time NASA launches a probe, it assumes on the basis of previous experience that the physical laws governing such a launch are sufficiently constant for them to plot a course to the craft's destination.
Postmoderns call everything into question, but I would argue that while we cannot know everything, we know from revelation, the experience of thousands of Christians whose testimonies we see and hear, and the ultimate coherence of the arguments that we can know "the faith once for all delivered to the saints" is absolutely true. It isn't just true for them. It isn't just true for me. It is true for all who choose to overcome their biases and heed the explicit and consistent testimony of the Word and the lives of others. Isn't that what brings us to faith? Doesn't the Scripture teach us we are "justified by faith"? (See Romans 3, Romans 10:19)