What is Reasonable Faith?
What makes a faith reasonable and who decides which faith is or isn’t reasonable?
Kelli, your disarmingly simple question is in fact a very profound and important one. If we’re going to name an organization “Reasonable Faith,” we’d better have a pretty good idea of what we’re talking about!
Let me address the first part of your question by defining the key terms. By “reasonable” I mean rational. Now what is it for a belief to be rational? According to Alvin Plantinga, the premier Christian epistemologist writing today, “rational” can be understood in either of two senses.
First, it can mean that the believer is within what Plantinga calls his “epistemic rights” in holding to the belief in question. The idea here is that people have certain obligations or duties concerning their beliefs. As I sit here at my desk, a computer appears to be in front of me. I would not be within my rights to believe that there is a horse here before me. Such a belief would therefore be irrational. On the other hand, my belief that there is a computer in front of me violates no intellectual duty and is therefore rational for me. Indeed, I’m inclined to say that such a belief is even rationally obligatory for me.
An alternative way of understanding what it is for a belief to be rational is in terms of what Plantinga calls a person’s “noetic structure.” A noetic structure is a person’s system of beliefs. Some beliefs will be based on other beliefs and so be higher up in the structure. But at the foundation of the structure will be a collection of basic beliefs which are not inferred from other beliefs but are taken immediately to be true in various circumstances in which a person exists. A person is rational insofar as he exhibits no flaw in his noetic structure. An example of a flawed system of beliefs would be one in which a person believed A on the basis of B and believed B on the basis of A, thus exhibiting circularity in his belief structure. Or a person might take a belief to be basic even though that belief is not properly basic for him (say, belief in the Great Pumpkin on no grounds at all); or he might deny a belief which really ought to be basic for him (Plantinga thinks belief in God should be properly basic for most people). A person who has a flawed noetic structure is irrational with regard to the flawed belief. A person who holds a belief without any sort of flaw with regard to it is rational in holding that belief.
Now it’s important to notice how extremely modest it is to say that a belief is rational or reasonable for someone to hold. In order for a belief to be rational for someone, that belief needn’t even be true, much less proven to be true, not to speak of known with certainty to be true. The person just needs to be within his epistemic rights or to exhibit no flaw in his noetic structure in holding to that belief. But the belief could turn out to be false. Isaac Newton, for example, was clearly within his rights in holding to the truth of the physics he founded, even though 300 years later it was discovered by physicists that Newtonian physics would have to be abandoned when it came to dealing with objects traveling at velocities near the speed of light. No one would say that Newton was irrational even though he turned out to be mistaken.
So in saying that Christianity is a reasonable faith, one is making a very modest claim, indeed! To make such a claim is not to say that Islam or atheism are not also reasonable faiths. Now obviously, I think that Christianity is not only rational but true and that its competitors are false. But my procedure illustrates what I call the principle of apologetical modesty. That is to say, rather than make extravagant claims for Christian faith that set the bar so high that it is difficult to reach it, it is better to set the bar low by making very modest claims and then to sail over it by demonstrating far more than what one has claimed. You thereby exhibit humility vis à vis the non-believer and exceed his expectations by offering evidence that is more than sufficient to establish your modest claim.
What, then, do I mean by “faith?” Again, there are two ways of understanding this term. On the one hand, one might mean the content of the (Christian) religion. In this sense, “faith” is used to designate the truth claims of the Christian worldview. We might in this sense contrast the tenets of the Christian faith with, for example, those of the Muslim faith. When we speak of faith in this sense we mean a body of doctrines. To say that faith is reasonable in this sense is to claim that these doctrines are rational for a person to hold.
On the other hand, “faith” may be taken to mean the act of believing. According to the Protestant Reformer Martin Luther, faith in this sense has three components. First, there is notitia, or understanding. That is, one must understand the truth claim being made. Second, there is assensus, or assent. One must accept intellectually that the claim is, in fact, true. One not only understands it; he assents to it or agrees with it. Finally, there is fiducia, or trust. Saving faith involves not merely intellectual assent to some doctrines but a whole-hearted commitment or trust in God, about whom the claims are made. To say that Christian faith is reasonable in this sense is to say that believing in the God of the Bible is a rational thing for a person to do. To take the step of faith is a reasonable step for an intelligent and informed person.
Contrary to all the angry and vociferous proponents of the so-called “New Atheism,” I’m convinced that Christian faith, so understood, is eminently reasonable.
Having said that, I now wonder if I’ve understood your question correctly. Perhaps you’re really asking, not for a clarification of what “reasonable faith” means, but for criteria for determining whether a particular faith is reasonable. If that’s the question, then I suggest you take a look at the first chapter of my book Reasonable Faith on “Faith and Reason.” For any faith to be reasonable it will have to be logically consistent and fit the facts of experience, whether these be scientific, historical, or whatever. Such systematic consistency, as it has been called, is only a necessary condition for the truth of a worldview, but it may be a sufficient condition as well for its reasonableness. For determining its truth one will need in addition either sound, non-question-begging arguments based on premises more plausible than their negations or else a way of knowing its truth in a properly basic way. I have argued that Christianity, in contrast to other faiths I’m familiar with, has both.
So who decides which faith is or isn’t reasonable? Well, obviously, you do! Each of us does. As Pascal said, the game is already in play; you must lay a bet. How will you choose?
Now in saying that you must decide, I in no way imply that the truth is determined by your choice. If you’re lost hiking in the mountains and must choose which prong of a fork in the trail to take, that wouldn’t imply that your choice determines which path will lead you to safety. On the contrary, which is the true path is already determined by the facts. But it is up to us to weigh the facts and so to make this momentous choice, often in deep anxiety and uncertainty.
But as Christians we know that no one is truly alone in making the choice to believe in the Gospel. For God has sent the Holy Spirit to convict the world and to draw people to Himself. Jesus has promised that “If any man’s will is to do God’s will, he will know whether my teaching is from God or whether I am speaking on my own authority" (John 7. 17). Ultimately, it will be God Himself who will judge whether a person in his historical circumstances made a rational decision.