Public and Private Epistemologies

[I apologise in advance for the style of this post. Since I have spent the last few weeks reading student papers, I am influenced by the way they often insist on explaining the most basic terms; thus an essay on the Nichomachean Ethics may begin "Philosophy means 'love of wisdom' in Greek. Aristotle was a famous Greek philosopher." It's also a way to force myself to think before I type.]

Traditionally, philosophy has three main branches: epistemology, ethics and metaphysics. Epistemology asks the question "How do we know stuff?" Ethics asks "What kind of stuff should we do?" and metaphysics asks "What is this 'stuff' stuff anyway?" but I'm not concerned with those here; this post is about epistemology. It's also about the public/private distinction, which is well-known in political philosophy but less so (if at all) in epistemology. The only reason it occurred to me to put them together was that this semester I had to teach texts by Karl Popper, who was a famous epistemologist, and Hannah Arendt, who sometimes talked about the public/private distinction.

So on to Popper and epistemology. Karl Popper is the best-known and most widely accepted sensible philosopher of science. I say "sensible" because there are also wacky philosophers of science like Feyerabend and Kuhn. Popper is popular with scientists because he describes what scientists think they ought to be doing, rather than what they often do in practice (that's Feyerabend) or would secretly like to do (that's Kuhn). Popper's main idea is that you can't prove a theory right, but you can, with reasonable certainty, prove it wrong. As he puts it, the claim that all swans are white only needs a sighting of one black swan to be consigned to the dustbin of science. It's a bit like programming: you can never be sure that you have a bug-free program, but you can be sure when you have a buggy one. On the other hand, although even "Hello world" could in theory contain a bug, we can be fairly sure that it is bug-free. Scientific knowledge is thus analogous to programs that have been tested so extensively as to be, for all practical purposes, bug-free (TeX, for example).

Now this strikes me as a pretty good model for what I'm calling "public epistemology". This is concerned with shared knowledge. I can know with absolute certainty that I am in pain, and it would be absurd for someone to say "You think you're in pain, but actually you aren't." However, I can't turn this certainty into public knowledge, since the person I'm complaining to may have reasons to doubt my honesty. Public knowledge requires some kind of verification, or in Popperian terms, there should be some way we can falsify the claim. If I claim, to use another famous example, that there are fairies at the bottom of my garden, there not only has to be some kind of evidence that indicates that there might indeed be fairies at the bottom of the garden, there has to be some conceivable way that we could prove that there are no fairies there. If I keep trying to wiggle out of the objections by saying that, for example, only people who believe in fairies can see them, then my claim may be dismissed as unscientific, and my neighbour may have evidence for a counter-claim that I'm completely batty. (Of course this claim too would have to be falsifiable, which is not as simple as it looks.)

But should my inability to establish the existence of garden fairies as public knowledge prevent my believing in them? I would say not. After all, I can be absolutely certain that I see fairies in the same way that I can be absolutely certain that I am in pain. The big leap is from here to the proposition that there are actual fairies that I am seeing. If I only see them when I have also been eating the funny little mushrooms at the bottom of the garden, I will probably doubt their existence, but if the visions persist, and furthermore, I start having long conversations with Tinkerbell, my belief in fairies will be confirmed, even if it is not falsifiable, and there is no possibility of my being able to convince anyone else of their existence. If someone else starts seeing them, then we're doing science (or shrooms); otherwise, this is private epistemology, and it looks like the rules for private epistemology are different, and perhaps closer to pragmatism: if it works for you, then believe it.

Coming back to Hannah Arendt, her point was that the public realm (which includes her book about Eichmann) and the private realm (which includes her affair with Heidegger) are equally necessary, but should not be mixed up. Applying this principle to epistemology, this is why I think some famous militant atheists are wrong. In its most extreme form, the argument goes: "The statement that God exists is not falsifiable, so anyone who believes in God is just plain silly." Falsifiability is a good rule of thumb for public epistemology (which concerns what we can expect other people to believe), but it doesn't apply to private epistemology (which concerns what we ourselves believe). On the other hand, this is probably less pernicious than the arguments of those who try to turn private epistemology into public epistemology, such as the creators of the Creation Museum.