Aristotle listed five different degrees of certainty. He listed them in order from highest degree to lowest degree. The strongest evidence we can have for believing something to be true is the knowledge that is self-evident. These are the truths that include life, liberty and the pursuit of happiness. These truths are their own evidence and most objective of the five listed. This is why Aristotle recognized them as the only kind of knowledge that is really knowledge in the strictest sense of the world. The other four kinds are increasingly more subjective. They are based on evidence obtained from the well-established opinions of mathematics, the conclusions of scientific investigation, the philosophical opinions that are based on our common experience and common sense from philosophical reflection, and finally, the opinions of historians which can be supported by historical and scientific research.
With the exception of true atheists who are in denial, the majority of people on the planet accept the premise that a creator exists because of the logic of cause and effect. We experience this creation with our five senses, and logic tells us that someone or something caused that creation to happen. This truth is self-evident. The belief that our creator is personal to us, however, is not self-evident. When we Christians examine why we believe in the triune God of the Bible, we have to concede that the most appropriate class of certainty of the five listed that applies to us in our belief is the last one, the historical evidence presented in the Bible. Yes, God communicates to us through our conscience, but that is even more subjective evidence than the historical evidence.
Historical evidence is the most subjective of the five because so much of it is based on eye-witness accounts, and we recognize how unreliable witnesses can be. But we also know that the majority of what we think we know we’ve learned from reading what someone else has to say about whatever it is we think we know; in fact, most of what we know is based on the historical evidence, so we have no choice but to give it much weight in our search for knowledge. Yes, it has its limitations, but so do the other sources Aristotle listed.
Unbelievers of course concentrate their attack on Christianity by attacking the credibility of our historical evidence, the Bible. They claim their unbelief is better supported because they rely on reason and scientific evidence, a more objective source of knowledge than history. But reason has its limitations too. All belief systems have to utilize a certain degree of faith in their beliefs because we just don’t know all the answers. Life is a mystery to all of us, and it will remain so until the day we die. I might point out here that unbelievers don’t even concede to know the questions much less the answers. As atheist philosopher Albert Camus once said, “We don’t aim so high.”
The Bible is the most analyzed book in history. Even unbelievers concede there has never been a book written in the history of mankind like the Holy Bible. Much of its account of the early history of the Middle East has been supported by the archeological evidence. The 40 or so writers were inspired by God to tell His story of our salvation. The 66 books included in the canon present us with a consistency of message and purpose unlike any other books every written. C. S. Lewis concluded that if the authority of any other historical source of information were attacked in the same way people question the authority of the eye-witness accounts presented in the New Testament, we would have to be content to know nothing at all of this life. We have no choice but to accept historical evidence as fact when it has met the test of credibility as the Bible has, time and time again. But, just because we understand what we are reading doesn’t mean we believe it to be true. This is where the degree of certainty is appropriately applied.
Christians concede that our evidence for belief in the gospel is weaker and more subjective than the evidence for unbelief, but those of us who accept the Bible as the very Word of God have been enabled by our God through faith to believe what Scripture tells us. For us who possess the faith God gave us to believe in the Bible as truly His Word, we believe what this book tells us. We believe this book that Lewis tells us has a “mythical radiance” is the truth, the only truth. For us, our faith is the strongest, most reliable indication of the truth with the highest degree of certainty; and, even if that faith is as small as a mustard seed, it is sufficient for our salvation.