Hi, so my name's Allan Hazlett, and this week we're going to be talking about testimony and the question of whether, and in what circumstances, you can believe what other people tell you. And we're going to talk about this the way people were talking about this issue during the Enlightenment. So the Enlightenment's a term that historians use to refer to a period in European intellectual history roughly 1700 to 1800. So people talk about what's distinctive of the Enlightenment. Some people would say, reason, liberal democracy, science, these are on the rise. Religion and monarchy, these are kind of fading out of popularity. What I want to talk about this week is an ideal or a virtue that contemporary philosophers call intellectual autonomy. I want to talk about how this notion of intellectual autonomy plays out in the thinking of some of the big names in the Enlightenment, and in particular the two big figures in the Scottish Enlightenment, David Hume and Thomas Reid. So Hume lived and worked in Edinburgh, Scotland most of his life. He's most famous for developing a completely naturalistic philosophical system. So by naturalistic, people mean a system that nowhere does it appeal to God in giving explanations of things. He's one of the first philosophers to ever have lots of things to say about almost all the different areas of philosophy, but he doesn't appeal to anything supernatural in any of it. He's also really well known for his spirited critiques of religion, had to keep these under wraps though in 18th century Scotland, you couldn't really be all that bold in your critiques of religion. So what I want to talk about is Hume's essay on miracles. It's a chapter in his book called an Enquiry Concerning Human Understanding, that first came out in 1748. So Hume's conclusion in the section on miracles is that you should never believe that a miracle's occurred on the basis of testimony. So to figure out why he drew that conclusion, we need to figure out two things. What does he mean by testimony? What does he mean by a miracle? So let's take that first part first. What is testimony? So philosophers use the word testimony to refer to any situation in which you believe something on the basis on what someone else asserts, either verbally or in writing. So someone else tells you something and you believe it. Or you read something that someone else wrote down and you believe what they say. Those are all instances of testimony. So Hume and other philosophers who write about testimony are really keen to point out that a ton of what we believe is based on the testimony of other people. So in the essay on miracles, Hume had this to say. He said, there is no species of reasoning more common, more useful, and even necessary to human life, than that which is derived from the testimony of men. Just to get a feel for what Hume's talking about, think of some city you've never visited before. Some city you've never actually been to. You've got a lot of beliefs about that city, beliefs about who lives there, population size, what it's like. All those beliefs are based on testimony, they're based on believing what people tell you who've been there. They're based on believing what you read in the newspaper about what's going on in that city. Based on reading the Wikipedia article about that city, stuff like that. So all those beliefs are based on testimonies. So Hume and other philosopher's writing about testimony are going to point out first thing, testimony's a really important source of beliefs for creatures like us. So now the big assumption that Hume makes about testimony in his essay on miracles is that to believe testimony, you have to have evidence that the person who's speaking or writing is likely to be right. So you have to have evidence of the reliability of the person who's testifying to you. He thinks that this assumption follows from maybe innocuous sounding assumption that philosophers call Evidentialism, a wise man proportions his belief to the evidence. So Hume thinks, well this applies when it comes to trusting someone else's testimony just as much as it applies in any other situation. So one thing he assumes is that if you're going to trust someone's testimony, you need evidence that they’re likely to be right or that they're reliable. And that if you're going to trust people's testimony in general, you need some evidence that people in general are likely to be right when they assert things or that they're generally reliable. You can see why this Evidentialist principle is true if you think about cases where someone testifies that's something unusual. So he says that the credit we give testimony, quote, admits of a diminution, greater or less, in proportion as the fact is more or less unusual. So imagine that you go into a cafe and you order a cup of coffee and the waiter says sorry, we don't have any coffee, the coffee machines broke down last night. So in that case, you're likely to believe what the waiter says and trust his testimony. But now imagine, same situation. You walk into the cafe, order a cup of coffee, the waiter says we don't have any coffee. Aliens broke in and stole all our coffee last night. So in that case you're not likely to believe, at least not as readily believe, what the waiter says. Likely to be doubtful or skeptical that the waiter's telling the truth. Or maybe the waiter's being sincere, but has gotten it wrong for some reason. So there's all kinds of ways in which someone can get their testimony wrong, and this is likely one of those times. So that's what Hume says about testimony. So now what does he say about miracles? What's a miracle? So he defines a miracle as, quote, a violation of the laws of nature. It's something that's never happened in what he calls, the common course of nature. So a miracle is an exception to a previously exceptionless regularity. It's something that's never happened before. So to take an example of this, someone rising from the dead, right? This is something that's never happened before. That's a paradigm example for Hume of a miracle. With this definition of a miracle in place, and with that assumption about testimony, we can now start to see why Hume concludes that you should never believe that a miracle's occurred on the basis of testimony. Here's how he articulates the argument in the essay on miracles. He says, no testimony is sufficient to establish a miracle, unless the testimony be of such a kind that it's falsehood would be more miraculous than the fact which it endeavors to establish. This is just another way of putting that assumption that you should only trust testimony when you've got evidence that the testifier is likely to be right. It's just another way of putting that assumption that the more unusual the event testified to is, the less trusting you should be of the testimony. So think again of that case of the cafe waiter. The reason you'd be inclined not to believe the story is because it's more likely that the cafe waiter is wrong about the aliens stealing the coffee than that the aliens really did steal the coffee. So now imagine that someone asserts that a miracle has occurred. For example, they say someone rose from the dead. So Hume thinks, treat this just like any other case and ask, what's more likely? That this person is wrong, for whatever reason, or that someone really did rise from the dead? The way he puts it, what's more miraculous? That someone really did rise from the dead, or that this person in this case is wrong for whatever reason? Well recall the definition of a miracle, that Hume gives us. A miracle is an exception to a previously exceptionalist regularity. So we've got all kinds of evidence, in every case of a miracle, we've got all kinds of evidence this event is very unlikely. The case of rising up of the dead, it's never happened before, so it's a very unlikely event because we've got all kinds of experimental evidence that it's not likely to happen. But now we need one more premise to see how Hume gets to his conclusion, and it’s a pretty innocuous assumption, people are often wrong when they testify. So people often assert things that are false, they assert things that are false because they sincerely say something they believe but they're wrong, and they assert things that are false sometimes intentionally. As when people are lying, or joking, or for various other kinds of reasons. So, we've got lots of evidence that a miracle is very unlikely, but we actually don't have very much evidence that false testimony is unlikely. We've actually got evidence that false testimony happens all the time. So we can now put all three of these assumptions, the assumption about testimony, the definition of miracles, and this premise about the unreliability of human testimony together. And we can see how Hume gets this conclusion out of them. So the first assumption he makes is that you should only trust testimony when you've got evidence the testifier is likely to be right. Second assumption he makes is that a miracle is an exception to a previously exceptionless regularity. In other words, something that's very unlikely. And the third assumption he makes is that people often assert falsehoods. False testimony isn't all that unlikely. And from those three, he concludes, you should never believe that a miracle's occurred on the basis of testimony. So to sum that all up, again, imagine someone asserts that someone has risen from the dead. So we've got lots of evidence that's really unlikely, we don't have all that much evidence at all that the speaker is wrong for some reason or other. In fact, we know people are often wrong in what they assert for all kinds of reasons. So it looks like this case is going to be exactly like the case of the cafe waiter. We shouldn't believe the testimony because it's more likely that the person testifying is wrong than that the event they're saying happened really did happen. And that's why Hume concludes you should never believe in a miracle on the basis of testimony.
