How do you KNOW Christianity is true?

It may be the single most prevalent question regarding Christianity. How do you know Christianity is true? This question also implicitly asks "how do you know all the other religions are false?"

Whether you are a Christian or of some other religious persuasion, chances are that you've had this thought yourselves or had it posed to you. The Christian will usually respond with a fairly short answer. They may refer to their upbringing in the Church, the teachings of the Bible, or their first hand experience. While these reasons may well be true and subjectively validate their own faith, they often leave the questioner vastly unsatisfied, often to the point of frustration. So what is the answer? What is the source of their frustration? How does a Christian respond?

Unfortunately, there is not an easy or quick answer. The question itself is loaded with presuppositions and assumptions that must be addressed first if any reasonable answer is to be given. Moreover, it may be the case that the questioner does not even wish to gain a reasonable response, but they rather wish to take an intellectual jab at what they see as an ignorant belief system. But even if that is the case, it is my firm conviction that the question allows the Christian to address many false assumptions that the questioner may carry while being gracious and loving.

It should be first noted that the question is not primarily one about Christianity. It is instead a question about knowledge itself! "How do you KNOW...?" There is a field of philosophy called epistomology which deals exclusively with these sorts of questions. We must all come to our own conclusions and answers to these very basic questions. How do we know anything? What is it exactly that we know? What constitutes knowledge? All of these questions are being indirectly addressed when someone asks "How do you know Christianity is true?"

There are two questions which seem to create a bit of a problem. The first being "what do we know?" and the second being "how do we know what we know?". It would appear that before we can move forward regarding questions of knowledge, we would need to answer these two questions. But if we venture to give an answer to the first question, say that we know snow is white, we would then need to ask ourselves how we knew that in the first place! So we would be needing to assume an answer to the second question in order to answer the first. On the other hand if we try to answer the second question, say that we know things by observation, then we claim that we KNOW that we know things by observation and simply assume an answer to the first question. This cyclical problem is called the problem of the criteria. There are only three answers to this problem. The first is the defeatest attitude, that we can't know anything. But this solution must be wrong, since the defeatest claims to KNOW that you can't know anything, thereby contradicting himself. The second solution claim that we must adopt an answer to the second question and give a set of rules as to how we know what we know. But this creates another problem. Say we know that X is true. Then this solution necessitates us to infer how we know X to be true. We may know X because of Y, but how do we know Y to be true. Because of Z, and so forth and so on. This becomes an infinite regression of "how do you know?" etc. etc. This is the position of the skeptic. In the end, this solution allows no real knowledge. The last solution attempts to assume some answer to the "what do we know?" question. This is, in my estimation, where most every thinking person begins their quest for knowledge. (Even the skeptic claims to KNOW that we can only know those things which we can verify with certainty, but he can't show that he KNOWS that with any certainty.) We all have a set of presuppositions and assumptions that we adopt without question, and we form every other belief and bit of knowledge off of them.

When a person asks "How do you know Christianity is true?", one must first ask in return how they believe we know anything at all. This isn't to be difficult, but rather to help identify where the questioner is coming from. If they are genuinely interested and assume that such knowledge is attainable, then you would proceed differently than if they are a true skeptic trying to intellectually outmanuever you. If the later is true, dealing with the actual apologetics that support Christianity may be initially fruitless. Instead, you may need to address the deeper foundational issues of the questioner's worldview.

A skeptic will define knowledge differently than will the Christian. They will demand absolute certainty as a prerequisite for knowledge while Christians and others like them will take a much more practical look at the evidence and decide which of the options on the table is more likely to be true. I will make the conjecture that we all, including the skeptic, must approach life from the non-skeptical, evidential point of view.

The skeptic will count the existence of an alternative logical possibility as grounds to reject a claim to knowledge. For example, you may respond to a skeptic with 300 pages of evidence regarding the historical accuracy of the New Testament, the lack of proven Biblical contradictions, and the thousands of manuscripts supporting the consistency of scripture, but they may say that it is still possible that it is some elaborate hoax and thus claim it is not possible to KNOW that it is true. This is the skeptical stance that requires certitude in order to have knowledge.

However, the skeptical mind can not function on this level all the time. For if the skeptic required certitude to know something, he would never be able to know anything, save for a few basic mathematical and self-evident truths. (Sometimes a skeptic will off that you can't be sure about anything, and they are sure about that. This is evidence that the position of the skeptic is, in the end, self-refuting.) It would never be possible for a skeptic to know who their mother is. Do they have a birth certificate, baby picture, witnesses, etc? Sure. But they could all be faked. It is LOGICALLY POSSIBLE to fake almost anything. The movie "the Matrix" showed that it is at least logically possible to fake all of existence with some elaborate computer controling the sensory input of all mankind. However, it is unreasonable to reject the reality aparent before us simply because it is logically possible computers are controling our brains. We must instead weigh the evidence.

I think this is the most crucial issue in the question "How do you know Christianity is true?" We must arrive at a place where we are allowed to weigh the evidence. This may mean we need to include other claims with Christianity on the table. Many other claims will have contradictions inherent in them. They can be rejected on such grounds. Others will stand to more intense scrutiny, but in the end may fail. But ultimately, the answer to the question "How do you know Christianity is true?" must be a process of coming alongside of the questioner, weighing the evidence and coming to a conclusion of what is probably true. In my experience, it is that the Christian worldview is the best and most comprehensive explanation of the world in which we live. I KNOW this like I know I have a mother and father, that I had cereal for breakfast, and that I am writing these words right now... even though it is at least logically possible those things are not true.

It is important in all of this that the Christian realize that the skeptical stance is real and is held closely to the heart of many who ask questions. We must always handle such conversations with care and gentleness. Arrogance does not make us intellectually wrong, but it is contrary to the love of Christ, who is the ultimate truth. We must be willing to come alongside all who are seeking truth in a gracious way. In this way, their struggle becomes our struggle, and we may all reason together.