In the previous post we addressed the question of what it means to know something. I defined knowledge as true, justified or warranted, belief. It is important to note that this is merely a definition of knowledge. A definition of knowledge cannot tell us whether a particular belief is really true or whether a particular person is really justified or warranted in holding that belief. The definition can be applied to particular cases only hypothetically. If we accept the definition of knowledge as true, justified or warranted belief, it follows that: “If belief A is true and person S is justified in holding A or possesses warrant for A, S knows A.” But the definition gives us no way to get past the little word “if.”

In other words, there is a huge difference between knowing A and knowing infallibly that you know A. (In my view, infallible knowledge is impossible apart from absolute knowledge.) And there is a huge difference between affirming the hypothetical statement, “If belief A is true and person S is justified in holding A or possesses warrant for A, S knows A,” and asserting categorically that “S knows A” or that “I know A.” In common speech, to say “I know A” asserts subjective certainty, and we learned last week that subjective certainty is compatible with falsehood. And to assert that “S knows A” is to express a judgment that A is true and S is justified or warranted in holding A. Clearly, this judgment is also fallible.

Every human act asserting an existential statement of the form “A” or “A exists” or “The belief that A exists is true” is fallible. Even if an assertion is true and is held in a justified or warranted way, the human act of judging a belief to be true is fallible. We cannot infallibly rule out every possible condition under which a belief could be false. The universal fallibility of human judgments makes doubt a real possibility for any judgment. Doubt is the subjective side of fallibility and the subjective opposite of certainty. Doubt no more makes a belief false than certainty makes it true.

We adapt to human fallibility and doubt in much of our lives, especially in those areas where the consequences of being wrong are not severe. In purely theoretical matters—if there are such things—or practical matters of little consequence, we shrug our shoulders and say, “Who cares?” In those areas we are able rather easily and routinely to make decisions and act in the absence of infallibility and complete certainty. We do not notice that our judgments and the actions based on them are fallible and involve risk. But when the stakes are high and great good or great evil may result from our actions, we become acutely conscious of our fallibility. Subjective doubt and anxiety arise and may paralyze us unless we find a way to deal with them.

Now I want to apply these thoughts to our question, “Is Christianity True.” If all human judgments are fallible and if in some really important matters, despite our best efforts to examine and weigh the evidence, we are forced to act on our fallible judgments, there will always come a point at which we must choose, decide, and act despite the risk. Hence in accounting for their Christian commitment, believers need not accept the obligation to “close the loop” and present conclusive proof for the truth of their faith. We can present the evidence and our evaluations of it, but we need not and cannot describe in rational terms the decision to act despite the risk. The necessity of acting on fallible judgments applies to all actions, trivial or monumental, enacted by believers or nonbelievers. Christian faith and commitment should not be held to a higher standard—that is, an impossible one—than other beliefs and commitments have to meet.

The necessity of decision and action based on responsible but fallible judgments determines much of my apologetic strategy and marks it off from many other approaches to apologetics. I hope to guide the reader on the road from unbelief to Christian faith. Along the way, we will come to certain natural decision points where progress demands that we choose one of two ways in the absence of conclusive proof. I will do my best to clarify the nature of the alternatives, the evidence for and against each, and what is at stake in the decision between the two. But rational arguments can take us only so far. Finally, one must choose and act despite the risk.