Scepticism as a engineering problem

Regular readers may remember that a while ago I was getting interested in scepticism. It was Peter Adamson’s fault, really. Well, I’m still interested in it. And I think basically that scepticism’s true. Here’s a picture of me defending it:

That picture was taken over a year ago, and I still haven’t written the paper. But I thought I might write some blog posts about it. This is the first.

A while back I was reading Peter Unger’s book about scepticism, which is called Ignorance: A Case For Scepticism. You pretty much have to read it if you’re defending scepticism. This is what I thought of it at the time, followed by a response from Aidan McGlynn:

And he’s right: it is a frustrating book. I don’t know why Aidan found it frustrating, but my problem with it is that the central argument is a bit silly. He argues that a lot of words are absolute terms, which means they only apply to cases at one end of a spectrum. If something could be flatter, it’s not flat. If something could be squarer, it’s not square. And if you could be justified in being more confident of something, or if you haven’t ruled out the possibility of some evidence making that thing seem less likely, then you don’t know it. In a lot of cases we’d ordinarily classify as knowledge, I guess you can’t completely rule out some new evidence coming in that’d make you more or less confident, so I guess if knowledge is one of these absolute terms, then a lot of everyday knowledge ascriptions are false, just like most flatness and squareness ascriptions. Unger hits you with this argument quite early on, and you think he’s just softening you up. You think he’s presenting a silly argument that shows his conclusion is technically true, before getting on to the real argument, the serious argument, the one that shows there’s something really problematic about our epistemic situation. You want him to argue that we’re never justified in being really confident about things. But if he ever does, I must have missed it. It was frustrating.

Now, you might wonder how else an analytic philosopher is supposed to argue for scepticism. Scepticism is the claim that nobody knows anything, or can know anything, or something like that. So as an analytic philosopher you analyse the concepts involved to get a more rigorous version of the everyday claim, and then argue for the rigorous version, either from premises people already agree with, or at least from premises they’ll agree with after going through your thought experiments. If the conclusion you come to from this method isn’t that big of a deal, that’s the method’s problem. And Unger pretty much agrees with this, which is why he also writes books about how most analytic philosophy isn’t that big of a deal.

I think there’s another way of framing the sceptical problem though, which doesn’t involve analysing the concept of knowledge, and doesn’t rest on any particular analysis of it. The sceptical problem is basically an engineering problem.

Think of all the opinions that right-thinking people have. They have strong opinions about what time it is, what happened a day ago, whether humans are causing climate change, what the capital of Sweden is, roughly how old the universe is, what stars are made of, and so on. Maybe they’re certain of some of this stuff; maybe they’re just pretty confident. Maybe there are also some things that a right-thinking person will think is between 60% and 70% likely, or whatever. In any case, there’s a credence distribution that sensible people will roughly have. Think for a bit about that credence distribution, in all its glorious and wide-ranging detail.

Now think about your evidence. You can perceive a few things around you. You’ve got some memories. You can do some tentative experiments: trying to move around, or rearranging the objects on a table, or looking behind you or underneath something. You can bring some memories to consciousness, you can ask yourself questions and test your dispositions to respond to them. You can type things into Google and get some results, and you can read the results. You can do some sums or concoct some philosophical arguments. You can get up and go somewhere else and be presented with the evidence over there instead. Maybe you can’t do all these things, and maybe you can do a few other things. The point is that when you really focus on it, your evidence can seem pretty limited. It can sometimes seem consistent with the solipsism of the present moment. In spite of this, you’re supposed to have all these strong opinions about remote things. So here’s the problem: how do you get from just this, to all that?

It’s not an argument, really. It’s a problem. You’ve got some tools and some raw materials, and you’re supposed to be able to do something with them. Your mission, should you choose to become an epistemologist, is to figure out to get from the evidence in front of you to roughly the credence distribution of a right-thinking adult. It’s a kind of engineering problem. It’s Descartes’s engineering problem. Descartes claimed that he could solve it, that he could start from premises that couldn’t be doubted and end up with something firm and constant in the sciences. You can argue how far he really believed he’d succeeded, but that is what he claimed. A simplified account of one version of his explanation is that you can argue fairly simply from pure reason and the contents of your own mind to the existence of a benevolent god who wouldn’t deceive you, and so if you do science as carefully as you can then you can be confident of the conclusions. Most people agree with the sceptics that this doesn’t work, but don’t agree with the sceptics that nothing works. I don’t think anything works, and that’s what puts me on the side of the sceptics. At least, I think it puts me on the side of the ancient sceptics, and Hume in some moods and maybe Montaigne and people like that. (I don’t know much about Montaigne and people like that.) I’m not sure Unger says anything much in his book to indicate that he and I are on the same side, though.

You can’t solve the engineering problem by analysing the concept of knowledge differently, because it doesn’t really use the concept of knowledge. It’s couched in some concepts, of course, and maybe you can try to undermine the problem with a careful analysis of those concepts. But what you really want is a story. Something like Descartes’s story, except plausible. You can tell a story about the raw materials, saying that perception has externalist content, or that we have acquaintance with Platonic forms, or that we have innate ideas. You can tell a story about the tools we have for constructing things out of those materials, bringing in externalist theories of justification, or inference to the best explanation, or talking about evolution. Maybe you can look hard at the maths of probability theory and see if there are any surprises there. And probably some of this storytelling can be and has been done under the auspices of conceptual analysis - analysing the concepts of perception, or justification, or whatever. But at the end of it, if it’s not a story about how we get from just this to all that, it’s not an answer to scepticism. That’s the story I don’t think can be plausibly told. And if you can’t tell that story, then you need to tell a different story about how an epistemically conscientious person will behave. I’ll sketch some of that story next time.