This question came from a discussion group, a Christian writer’s group.
Reality places some restrictions on what’s rational and what’s not. “Reason” is the first book in the set, and it covers the subject comprehensively. It’s 410 pages on 8.5X11 in #12 Times Roman font. Most of that is dealing with misconceptions and objections, so I’ll give you a quick summary without trying to deal with all the questions that the book answers. Because of the brevity, it may seem a bit stuffy.
Here’s a short version of the basics of how we can know anything about anything. Knowledge of truth requires a true premise and valid deductive form. Neither inductive nor abductive reasoning can get us to the truth. That’s commonly taught in logic books and classes everywhere. Yet, the classes and books seem to ignore the ramifications. They allow premises that no one can prove.
On their own, our human minds have no path to true premises. When we observe anything or read Scripture, we can’t go beyond what we see without adding information. Without divine revelation, we get that information by making it up, which we call making assumptions or using axioms. Axioms come from our worldviews, so they seem more real than reality. We need Jesus Christ if we’re to go beyond what Peter and Jude say is like a “brute beast.” The brute beast mind can react to the environment. It can be very clever, and it can do science. This mind can be ever learning, but it can never come to the knowledge of the truth.
Jesus Christ is real. I know this because I know Him. Everyone who seeks Him finds Him, and He leads, teaches, and corrects us moment by moment. God speaks through Scripture and every means mentioned in Scripture. Anyone can test this. The reason that we know that the Bible is God’s word (utterance) without error is that the Holy Spirit speaks this into our hearts. There are many facets and pitfalls concerning divine revelation, and I go into those in detail in the book. We’ve probably all met people who said “Thus sayeth the Lord” when God never spoke. We’ve also probably met people who said “The Bible says” when the Bible says no such thing. That being said, God tells us that He’s a good Father and well able to give the Holy Spirit to those who ask for the Holy Spirit. He won’t give us a stone instead of bread or a serpent instead of a fish.