How do I know Christianity is real? This is the favourite question of every honest Christian but the least favourite question of any Christian leader faced with the task of answering it.
My question in response to the question is this - how do you know anything is real? This is what philosophers call an ontological (ie. truth) question - ie. how do you determine truth. Everyday in my job, I have to listen to different people tell completely different versions of the same event and then make up my mind on who is telling the truth. The ascertainment of truth in the court of law relies on testimonial evidence and where available, physical evidence. This itself is fraught with its problems. How then do we determine truth?
May I suggest that to determine truth is a two-stage process.
(1) Stage One - Test the Source. All truth comes from a source, ie. the testimony of a witness, or the observation and interpretation of physical evidence. To determine the veracity of this truth, we must therefore first test the veracity of the source. The assumption is that if the source is valid, then the statement of truth that comes from that source must be valid. ie. if a witness is truthful and trustworthy, then what he says must be true.
In the ascertainment of truth about life and God, there are three primary sources: (1) Science, (2) Reason and (3) Revelation. The ascertainment of truth by way of science has long been lauded as the unshakeable source. One may say the evidence does not lie. While that is true, the interpretation of the evidence is something that is far from certain. To speak as if all of science speaks in unison is to deceive oneself. Scientists differ on the state of the universe, the origins of the universe, the immutability of scientific laws, and the causes of disease. While the physical universe is there for all to see, our inadequate human faculties and our limited experiential paradigms make our interpretation of from scientific data as to what is ultimate truth far from reliable. In short, we cannot extract truth from science without the operation of human reason. Yet because of the failings of human reason and our limited experiences, any attempt to extract truth from science is fraught with uncertainty. What is more, in the area of the metaphysical (or spiritual), in the issues of life beyond death, scientific data come to an almost embarrassing standstill. Science has simply no answers.
Where science fails because of the frailty of reason, divine revelation takes over. While science requires finite man to make conclusions about life and death and existence and God, revelation stems from the divine Himself. Immediately, the superiority of the primary source becomes clear. To put it another way, who would you trust to tell you about life after death - a monkey, an evolved form of a monkey (no offence) or the divine himself?
(2) Stage Two - Test the Messenger. Even if the source is valid, the transmission of that statement of truth to the end point may be corrupted by inadequacies in the communication process. For example, even if the speaker is saying something true, if there is so much noise that I cannot hear what he is saying, then the communication of that truth to me is lost.
Assuming that we accept the superiority of revelation over science, we now move to the second test. Here we move from testing the source to testing the transmission process stemming from that source. Every religion with exception of Christianity relies on the transmission of the divine message through a human conduit, ie. a prophet, a messenger or a holy man. To test the divergent truth statements made by all these human conduits, we must look at the quality of messenger himself. This is where Christianity distinguishes itself. In all the major world religions, no other messenger of the truth statement has claimed to be divine himself. All else has claimed to simply be a messenger for the divine. In Christianity, the transmission of the truth statement stems from the lips of the divine Himself, incarnated as man. In all other major world religions, the message is "Let me point you to the truth". In Christianity, the message is "I am the truth."
In conclusion, Christianity provides both the superior source and the superior transmission of the message from that source. If I had to chose to place my faith in a religion, the choice, as you can see, is not so difficult to make.