Really wanting to know the Truth means at least two things: 1) It means that we are willing to expend some effort; and 2) It means that we are not going to put any preconditions on Truth.
Now, in our search for Truth, we are going to run into a myriad of truth-claims. After all, everyone thinks his view on things is the correct one. How shall we know which one to hold to? This is where #1 above comes into play. We will have to spend some effort and do some digging. Now, we can make the task difficult, or impossible, by looking at the myriad claims that exist in our world and be overwhelmed by the task, or we can cut through the trash and set up some very basic standards that all people freely acknowledge will lead to some level of truth.
The first of these standards is rationality. If the accurate use of logic is not a guide to truth, then there is no use in pursuing the knowledge of the truth because even if we stumbled across it, we wouldn't know what we had stumbled across. Believe it or not, logic is the fundamental element that allows us to function in this world. Without logic we couldn't find our way out of a room; we couldn't learn anything; and we would die sooner than later. Logic is the tool that all men use from the very beginning of their lives in order to build understanding, one brick at a time.
The second of these standards is experience. Truth corresponds to what is real. Experience is how we often find out what is real. No one in his right mind denies the reality that all men everywhere learn from what they experience.
There is a flaw in the pure use of logic; it requires that we have the right premise, and that we make our deductions accurately. We don't always succeed in this, so experience comes along as an aid to correct us when we are wrong, and to reinforce us when we are right. Thus, logic and experience work together for our good.
These are universal standards of the measure of truth. Reason and experience. With these tools at our disposal, we approach the myriad truth-claims that exist.
Now, in our approach, it makes good sense to subject the major claimants to scrutiny first--for it is likely that Truth will have made a significant impact in the world since men have been on the earth. That is not automatically true, but it does have a certain appeal, and if it is correct it will save us a lot of time and energy. That means that we only have four avenues of pursuit open to us: Christianity, Judaism, Islam, and basic paganism.
Three of these four are easily dismissed as repositories of Truth by our twin helpers--reason and experience. Islam, for example, cannot be true because it contains a fundamental contradiction in its teachings about Christianity. In the writings of the prophet, he declared that Jesus Christ was a great prophet of the true God, Allah. By so doing, he destroyed his identity as a prophet, for Jesus Christ was either far more than a prophet or He was a liar, self-deluded and deluding the unwary. Logic thus disposes of Islam immediately. More in another article. (168)