I have a Christian friend who says that we can know nothing empirically. He goes far enough to say that nothing can be proven with certainty.
This has been bothering me because I cannot show that he is wrong. Is there a way to deal with uncertainty in our lives?
Your friend is right on one account and wrong on another. It is true that we can know virtually nothing with certainty (that is to say, to such a degree that it would be impossible that we were wrong). Some philosophers will say that analytic truths and logical truths can be known with certainty (things such as, “Blue houses are blue,” or “1 + 1 = 2”), but most of what we know would fall out of such a strict requirement.
Where your friend is wrong is in thinking that this means we can’t know anything. Just consider the question, “Do you know that you are now using an electronic device?” It seems self-evident that your awareness that you are using an electronic device counts for knowledge. Since it is *possible* that you are wrong (you could be in some sort of coma and be dreaming the whole thing), you cannot be *certain* that you are using an electronic device. So here we have an example in which it is self-evidently obvious that you know something even though you are not certain of it. This implies that certainty is not a requirement for knowledge.
So what is required for knowledge? Philosopher Alvin Plantinga made the case that “warranted true belief” is what is required for knowledge. If you are warranted in believing something and you do believe it, then you “know” it if it is true. The “true” requirement here simply makes the concession that if it turns out something is false then it will turn out that you did not know it. If one asks, “Well how do you know it is true?” this is a question about your warrant for the belief. If you are warranted in believing it (which entails being rationally justified in believing it) then you take it as true.
As it turns out, we can know a great deal even if we are not certain. Even so, I often try to side-step the whole issue in discussions by shifting the language into, “What is most reasonable to believe?” This very clearly takes the “certainty” requirement off the table and can sometimes allow the discussion to proceed without having to work through that obstacle.
Chapter Director, Reasonable Faith
Master of Arts in Apologetics, Luther Rice University and Seminary