The world is awash with divisive arguments, conflict, fake news, victimhood, exploitation, prejudice, bigotry, blame, shouting and minuscule attention spans. It can sometimes seem that we are doomed to take sides, be stuck in echo chambers and never agree again. It can sometimes seem like a race to the bottom, where everyone is calling out somebody else's privilege and vying to show that they are the most hard-done-by person in the conversation. How can we make sense in a world that doesn't? I have a tool for understanding this confusing world of ours, a tool that you might not expect: abstract mathematics. I am a pure mathematician. Traditionally, pure maths is like the theory of maths, where applied maths is applied to real problems like building bridges and flying planes and controlling traffic flow. But I'm going to talk about a way that pure maths applies directly to our daily lives as a way of thinking. I don't solve quadratic equations to help me with my daily life, but I do use mathematical thinking to help me understand arguments and to empathize with other people. And so pure maths helps me with the entire human world. But before I talk about the entire human world, I need to talk about something that you might think of as irrelevant schools maths: factors of numbers. We're going to start by thinking about the factors of 30. Now, if this makes you shudder with bad memories of school maths lessons, I sympathize, because I found school maths lessons boring, too. But I'm pretty sure we are going to take this in a direction that is very different from what happened at school. So what are the factors of 30? Well, they're the numbers that go into 30. Maybe you can remember them. We'll work them out. It's one, two, three, five, six, 10, 15 and 30. It's not very interesting. It's a bunch of numbers in a straight line. We can make it more interesting by thinking about which of these numbers are also factors of each other and drawing a picture, a bit like a family tree, to show those relationships. So 30 is going to be at the top like a kind of great-grandparent. Six, 10 and 15 go into 30. Five goes into 10 and 15. Two goes into six and 10. Three goes into six and 15. And one goes into two, three and five. So now we see that 10 is not divisible by three, but that this is the corners of a cube, which is, I think, a bit more interesting than a bunch of numbers in a straight line. We can see something more here. There's a hierarchy going on. At the bottom level is the number one, then there's the numbers two, three and five, and nothing goes into those except one and themselves. You might remember this means they're prime. At the next level up, we have six, 10 and 15, and each of those is a product of two prime factors. So six is two times three, 10 is two times five, 15 is three times five. And then at the top, we have 30, which is a product of three prime numbers -- two times three times five. So I could redraw this diagram using those numbers instead. We see that we've got two, three and five at the top, we have pairs of numbers at the next level, and we have single elements at the next level and then the empty set at the bottom. And each of those arrows shows losing one of your numbers in the set. Now maybe it can be clear that it doesn't really matter what those numbers are. In fact, it doesn't matter what they are. So we could replace them with something like A, B and C instead, and we get the same picture. So now this has become very abstract. The numbers have turned into letters. But there is a point to this abstraction, which is that it now suddenly becomes very widely applicable, because A, B and C could be anything. For example, they could be three types of privilege: rich, white and male. So then at the next level, we have rich white people. Here we have rich male people. Here we have white male people. Then we have rich, white and male. And finally, people with none of those types of privilege. And I'm going to put back in the rest of the adjectives for emphasis. So here we have rich, white non-male people, to remind us that there are nonbinary people we need to include. Here we have rich, nonwhite male people. Here we have non-rich, white male people, rich, nonwhite, non-male, non-rich, white, non-male and non-rich, nonwhite, male. And at the bottom, with the least privilege, non-rich, nonwhite, non-male people. We have gone from a diagram of factors of 30 to a diagram of interaction of different types of privilege. And there are many things we can learn from this diagram, I think. The first is that each arrow represents a direct loss of one type of privilege. Sometimes people mistakenly think that white privilege means all white people are better off than all nonwhite people. Some people point at superrich black sports stars and say, "See? They're really rich. White privilege doesn't exist." But that's not what the theory of white privilege says. It says that if that superrich sports star had all the same characteristics but they were also white, we would expect them to be better off in society. There is something else we can understand from this diagram if we look along a row. If we look along the second-to-top row, where people have two types of privilege, we might be able to see that they're not all particularly equal. For example, rich white women are probably much better off in society than poor white men, and rich black men are probably somewhere in between. So it's really more skewed like this, and the same on the bottom level. But we can actually take it further and look at the interactions between those two middle levels. Because rich, nonwhite non-men might well be better off in society than poor white men. Think about some extreme examples, like Michelle Obama, Oprah Winfrey. They're definitely better off than poor, white, unemployed homeless men. So actually, the diagram is more skewed like this. And that tension exists between the layers of privilege in the diagram and the absolute privilege that people experience in society. And this has helped me to understand why some poor white men are so angry in society at the moment. Because they are considered to be high up in this cuboid of privilege, but in terms of absolute privilege, they don't actually feel the effect of it. And I believe that understanding the root of that anger is much more productive than just being angry at them in return. Seeing these abstract structures can also help us switch contexts and see that different people are at the top in different contexts. In our original diagram, rich white men were at the top, but if we restricted our attention to non-men, we would see that they are here, and now the rich, white non-men are at the top. So we could move to a whole context of women, and our three types of privilege could now be rich, white and cisgendered. Remember that "cisgendered" means that your gender identity does match the gender you were assigned at birth. So now we see that rich, white cis women occupy the analogous situation that rich white men did in broader society. And this has helped me understand why there is so much anger towards rich white women, especially in some parts of the feminist movement at the moment, because perhaps they're prone to seeing themselves as underprivileged relative to white men, and they forget how overprivileged they are relative to nonwhite women. We can all use these abstract structures to help us pivot between situations in which we are more privileged and less privileged. We are all more privileged than somebody and less privileged than somebody else. For example, I know and I feel that as an Asian person, I am less privileged than white people because of white privilege. But I also understand that I am probably among the most privileged of nonwhite people, and this helps me pivot between those two contexts. And in terms of wealth, I don't think I'm super rich. I'm not as rich as the kind of people who don't have to work. But I am doing fine, and that's a much better situation to be in than people who are really struggling, maybe are unemployed or working at minimum wage. I perform these pivots in my head to help me understand experiences from other people's points of view, which brings me to this possibly surprising conclusion: that abstract mathematics is highly relevant to our daily lives and can even help us to understand and empathize with other people. My wish is that everybody would try to understand other people more and work with them together, rather than competing with them and trying to show that they're wrong. And I believe that abstract mathematical thinking can help us achieve that. Thank you. (Applause)