“Nevertheless, there are good reason for rejecting skepticism.
First, much of skeptical thought is either self-defeating or impractical. Consider the unmitigated skeptic’s claim that “I know that no one has any knowledge.” To say that it is impossible to have knowledge is itself a knowledge claim, and thus this position is self-defeating. Furthermore, this approach is contradicted by our actions, because no one lives this way. Our lives require knowledge of many different things in order to function properly, and yet, for the most part, we manage to live our lives quite well. How is this possible if we know nothing about the way things are? Thus, unmitigated skepticism is highly problematic. But what about mitigated skeptics who simply believe that it is impossible to have knowledge? This approach might be less obviously self-defeating than a mitigated skeptic, “Do you know that you believe no one knows anything?” In order to avoid the self-defeating error of the unmitigated skeptic, he might reply, “No, but I believe it.” But then we could ask, “Do you know that you believe it?” He may continue to claim that he does not know, he just believes it, but now he has a problem because he has no ultimate basis for his belief. He ends up in an infinite regression of belief claims without ever being able to justify any of them. So, mitigated skepticism is just as problematic as unmitmigated skepticism.
Second, despite the occasional perceptual difficulties we might have, there are good reasons to think that we do have knowledge of the world. While it is true that we can be misled by our senses, it is also true that they give us good information more often than not. Take, for example, the information you get from your senses as you drive down the road in your car. Suppose you are driving down a two-lane road- one lane going north and the other going south- and a massive eighteen-wheeler is approaching you. Both you and the eighteen-wheeler are traveling at about sixty-five to seventy miles per hour, and as the truck gets closer to you, you notice that it swerves into your lane. What do you do at this moment? Do you pause for a time of reflection about the reliability of your senses- wondering whether or not you can trust the information they are giving you- or do you hit the brakes and swerve? You swerve! But why do you do this? You do it because failing to do so would cause you- and any loved ones you have in the car with you- to be killed. Skeptics raise good philosophical points for us and remind us that we can make errors in our thinking. But suggesting that we cannot trust our senses is both dangerous and foolish. The fact is, as the case of the swerving eighteen-wheeler reminds us, our senses give us important information about the world that is, in most cases, true. We are also reminded of this when we consider the progress of the natural sciences over the past few centuries. Because of this progress, we now have the ability to do open-heart surgery, put people on the moon and fly around the world in less than twenty-four hours. How is any of this possible if our senses tell us nothing about the world?
Third, skeptics have raised important considerations about the possibility of having metaphysical knowledge. But their criticism overstate the case. It is true that geting this kind of knowledge is difficult. But difficult does not mean impossible. In recent philosophy, there has been a resurgence of metaphysical discussion by both believers and non-believers. We now recognize that certain scientific and mathematical inquiries thrust us directly into the domain of metaphysics. This may indeed be a chastened approach to metaphysics, but it is metaphysics nonetheless. Moreover, as we noted in chapter 9, having some form of divine revelation makes metaphysical knowledge a possibility.
Finally, skepticism implies that knowledge requires absolute certainty. However, this expectation sets the bar too high and is unrealistic. As W. Jay Wood puts it:
The strict demands for unimpeachable certainty leave one with so small a set of basic beliefs that they can’t possibly bear the heavy weight of all that we believe. A moment’s reflection shows that the thousands of beliefs we hold about matters aesthetic, moral, religious, political, economic, historical, scientific, philosophical, and so on can’t all be derived from the very small set of basic beliefs insisted on by strong foundationalists.”
If certainty is required, then skepticism has a much stronger case. But if certainty is not required, then skepticism is weak. We might not have an absolute certainty about many things, but this does not mean that we know nothing about them whatsoever. So the next question is, “Do we need certainty in order to have knowledge?”
(Dew & Foreman, How Do We Know?)