I'm often disappointed to see how little people understand the concept and use of reason. Reason is typically seen as the buzzword of intellectuals who engage in debate and lay out formal argumentation in books or articles. Yet we all utilize the tool of reason on a daily basis, in ways that most of us probably are not aware of. Even when you view a painting in an art gallery and think to yourself, "I like this. It would go well in my living room," you are reasoning that purchasing the painting would be beneficial in the enjoyment it would bring to yourself and to your guests, perhaps. Reason is how we make sense of things in our world - it's how we make choices, how we verify information, and how we communicate to others why we have made a particular choice and why we do, or do not, accept certain information.
Aside from reason there is no other method for assessing truth that has shown to be reliable. Personal experience is sometimes suggested, but we all interpret our experiences, and these interpretations are always made from reason. They may not be reasonable, but they do use reason, even if incorrectly. This is why many miracle claims are accompanied by reports of the numbers of people present, the slant of those involved, the improbability of the event, and more. Even believers in the supernatural recognize that reason is a vital part of making a persuasive argument to others. Asking us to believe without reason is far less likely to result in a successful conversion than providing bad reasons to believe.
Recently I talked to an individual who said that he believes that there is more truth out there than what we can find through science and reason. There are also truths in religion, poetry, and metaphor, he said. I don't say that science is all there is because, for one reason, I know that science misses the significance of things like poetry, music, literature, and other media. I do believe there is some truth in religion, as well as poetry and metaphor, but there is still one step left out, which is how one finds these truths from such sources. Again, the only reliable method is reason. Using reason, we can take a story like Jesus and the adulterous woman, or Shakespeare's thoughts on mercy in Act 4 of The Merchant of Venice, and we can apply them to our lives and to the facts of the world at large to find their meaningfulness and, in that sense, find truth.
How else is one to find these truths? One has to first understand the passages before they can be appreciated, and part of appreciating them means uncovering how they relate to us. Since reason is how we make sense of things in our world, we use reason to interpret passages of scripture and poetry, just as we use it to interpret personal experiences. Any time you try to figure things out, reason is involved. The funny thing is that this person, in trying to persuade me of his belief that reason and science are not "all there is," was forced to use the only tenable method he has: reason. And in fact, all of our beliefs are dependent on reason.
Since we can't believe what we know to be false, we must think something is true if we believe it. In order to regard something as true, we have to have some basis for considering it true, whether personal experience, evidence, hearsay, loose connections, or whatever. We don't just suddenly and arbitrarily decide that something is true, we figure out that it's true (even if we're mistaken). By good use or bad use, we have come to hold the beliefs we now hold thanks to reason. This may be one of the most powerful realizations in understanding the place and value of reason in our thinking. Even the belief that reason is limited requires reason to be sustained.