by Scott F. Aikin and Robert B. Talisse

Epistemology is the philosophical study of knowledge. Its main questions are: What do we know?; How do we know it?; and What distinguishes knowledge from lucky guesses, sheer dogmatism, and simple ignorance? The application of this discipline seems pretty obvious in the sense that our answers to these questions will then allow us the means to sort out many of the factual questions before us. A model for knowledge yields a model for inquiry, which, when put in to practice, resolves our disagreements. This is the old school story of the relevance of epistemology. It goes back to Xenophanes, who held in the hymn to progress that even though the gods didn't give us all the truths, we are better off inquiring. This thought runs from the ancient through the modern period to Descartes, who held that his exercises were for the sake of providing a means for philosophy and science to proceed with powerful criteria for progress. And this thought is alive even now with the applications of epistemology by Michael Lynch in his recent In Praise of Reason and Paul Boghossian in his Fear of Knowledge. The Cato Institute's Juan Sanchez's use of the term “epistemic closure” to criticize conservatives for their bad intellectual habits of know-nothingism, too, is in this tradition.

We think the old school story is right, at least in its broad outline. An epistemology is a useful thing to to sort nonsense from the things worth deliberating about; an epistemology is also useful as a guide for deliberation. But there's a problem in the background, and it's one that's regularly been pointed out about a number of high points in the Western tradition. It runs like this: Often, these epistemologies, for all their promise of being deployments of critical thinking, end up being merely dressed-up apologetics for the authors' preferred beliefs. Descartes is regularly the prime target for this criticism – his method was to doubt everything in order to find criteria for truth that could not be doubted; and once he found those criteria, they were used to endorse the core commitments of the Catholic Christianity to which Descartes had ascribed. How convenient, says the critic. And reasonably so.

The old school case for the significance of epistemology was that with the right set of epistemic principles, you can do the good work of sorting the true from the false. That is certainly a reason to want to have a correct epistemology. But then the trouble starts, as pretty much everybody running the old school line has a different story about what the correct set of epistemic principles are. And this is where our critic from before begins to get giddy. The variety of distinct and inconsistent views on the correct theory of knowledge is evidence that we're likely not able to formulate one. And so, the critic concludes, even if it would be good to have a true epistemology, it's not something we can have. So the project is worthless, kaput.

The dull dustiness of a good deal of epistemology done in the contemporary academic vein, with its ‘S knows that p at t' schemata and fierce logic-chopping, doesn't help much with the discipline's appeal, either. It's hard to make the case that the finer points of some technical principle about, say, epistemic defeat has real practical payoff. What's the relevance to life in this discipline?, our critic may challenge.

Well, in fact epistemology pays off in a number of ways, and we don't have to have the thought that we've got the true epistemological theory for sorting the true from the false in our hands to show that. We think that some of the core distinctions shared by most epistemologists and deployed for arguing for their substantive views are of real use to our lives.

For instance, in epistemology a distinction is frequently drawn between the truth of a person's view and the reasons the person has for holding it. Sometimes, we can have very good reasons, but be wrong. Those are called fallible reasons, and inductive reasoning is comprised of them. So if you have reason to believe that L is a bird and that most birds fly, you have reason to believe that L flies. If it turns out that L is a penguin, you are wrong. But you still directed your beliefs correctly, given the evidence you had. And so we can have correct, or blameless, performance, but incorrect output.

Consider another distinction, this time between how much evidence someone has and how much evidence they should have. Imagine buying a house, and the owner telling you that it's in great shape. Now, that's evidence that the house is in great shape. But it is very weak evidence. You should get an independent inspector – someone not highly motivated to sell the house regardless of its condition and with experience in assessing the shape of houses – to look it over. If you were to buy the house without the inspection, you would be pretty reckless. Even were the house come out to be just fine, you not only could have, but should have done better.

Notice that these two distinctions have an interesting synergy, too. If we have fallible reasons, sometimes, we may have pretty good reasons, but we could have better. The question is when the could becomes a should. In the penguin case, would it have been reasonable to ask someone if L is a penguin or emu before concluding it could fly? Perhaps, but likely only if we were concerned that L might be one. In the house-buying case, it was reasonable to get the first inspection. But that's a fallible reason, too, so would a second, third, fourth . . . inspection be needed? When is it OK to say one has sufficient evidence? Our inclination is to say that the answer here is to be determined in terms of the error costs associated with the decisions and the costs of further inquiry (a kind of epistemic-economic issue, one about which many pragmatists have views). But this takes us back into substantive epistemology, which, as we can see, is important. Now, however, epistemology is relevant not because it gives us the keys to the right answers, but the tools to deliberate about how to proceed with our lives. That is, epistemology is largely concerned to discover criteria for proper conduct. What could be more relevant than that?