[MUSIC] I just gave three examples, three examples from the book by Church and Samuelson. The first was about climate change, and the second was about used car salesmen, and the third is from the movie The Talented Mr. Ripley. They all have to do with the hearer. There are cases where the hearer is not being intellectually virtues by not responding to the available evidence. But there's also pressures on speakers, so hearers rely upon speakers for information. And there are tricks that often get used to get people to believe you. One trick that often we're not even aware of, just as we're not aware of our implicit biases, is confidence. One way to get someone to believe you is by presenting your evidence, by making your report or your assertion or giving your testimony in a confident manner. Confidence influences people. Often by being confident we see that people believe us. And that's a kind of reward. It makes us feel good. That we have that kind of influence. That we've been able to achieve for our intended effect. And that we start by being more confident when we're making our assertions. We could be entirely unaware of this, just as we're unaware of our implicit biases. So some of us, by being confident, have an effect on other people that we don't even know that we're having. Now suppose you're not believing on the available evidence as a speaker. That is suppose you're not being entirely intellectually humble, and that you're being overconfident or perhaps underconfident vis-a-vis your evidence. But then you're very confident when you make an assertion. When you do that you're going to get someone to believe on your belief. And if your belief isn't well based on the evidence, then the belief that they will inherit from you will not be well based on the evidence either. So if we're going to help other people by making assertions instead of helping ourselves by feeling influential when making assertions, then we need to make sure that when we do so, that when we tell someone something, when we give testimony, when we make a report, that we really know what we're talking about. So we shouldn't be overconfident. Our confidence in our delivery should match our justified confidence in the evidence that supports our belief. This can be difficult to do so, and often times it takes that kind of courage or openmindedness to overcome some of our fears and anxieties. We're worried they might not believe us. We're worried they might disagree with us. We're worried they may not think well of us. And so we speak in a confident way to have that kind of influence on others. But sometimes we might be better off by signalling that perhaps we're not so sure. That perhaps the evidence could go the other way or that we don't have all the evidence. And in that way we're more likely to share what's likely to be true with another person and genuinely benefit them. So intellectual humility comes in not just for hearers when they are arguing with another person, or filtering the reports, or wondering whether to believe them, but it also comes in for speakers too. It's a joint enterprise sharing information speaker to hearer. And not just two people, not just interpersonal, but larger groups. Because you never know who you're going to talk to or who you're going to pass information on to that someone else gave to you. I don't mean to suggest that the kinds of issues that we're talking about are simple or just interpersonal. They're much bigger than that. And many of the issues we face, I just gave you the example of climate change, are issues that we all face that have to do with large social institutions that go well beyond just talking to one another, just acquiring information through testimony. But testimony is nevertheless one of those very interesting cases where we acquire information about the world. Remember philosophers. They ask big questions. Very big questions. What is there? What should I do? What should we do? How do you know? And when it comes to knowledge, philosophers are very interested in knowledge of the world. Propositional knowledge, not just of the physical world but the social world too. I want to know about you just as you want to know about me. That kind of knowledge, factual, propositional knowledge is a true belief, a belief that matches reality that's based on evidence. And what are the various kinds of evidence that we have? David Hume is right, he thought there was no species of reasoning more common, more useful, and even more necessary to human life than the testimony of others. We are learning from one another as a social species all the time. It's extremely important that we're able to rely upon one another, which means it's extremely important that as hearers we don't just believe what other people tell us, but also as speakers we're providing useful information to others. We often fall short in providing the best possible information and forming the best possible beliefs and response to what other people tell us. Often they have motives to mislead, often we have motives to ignore the evidence that they're providing. But the intellectually virtuous person overcomes those kinds of motives. Usually their emotions, usually their fears, and it's difficult. It's demanding. But as we do so we grow. Remember, for any particular case where you might be afraid of the evidence, or you might be afraid of the conclusion, ask yourself, if it's true what happens and if it's false what happens? And how am I going to be better off in those two types of circumstances? When you might be sick, go to the doctor. You'll be better off either way. When there's amazing change to the entire world that could be right around the corner, that's another kind of case. Though it may be very scary, we will all be better off if we know the truth about it.