In the beginning, I will lead you to look at the definition of "Youth". You might be curious that Youth, Why do we need to define this word? Before I talk about the definition of Youth, I want to ask you, What do you think when I mention "Youth"? Who will be considered a youth? I will lead you from the biological, psychological, and sociological points of view to see who is youth Let's begin with the biological point of view. How old is youth? In fact, there is not group of youth in biology. Because when a person's body changes, the secondary sexual characteristics appear, we already have had the ability to raise the next generation, and we should consider them no longer children. If not children, they must be adult. Because they have the ability to give birth to and raise their children. This is biological point of view. How about the psychological point? What is "Youth" in psychology? Most of the time, you know that youth is in a period which we called "stress and storm" in English. "Storm" is like a storm. The children's mood at this period changes quickly. "To write a song pretending sadness" and "The Sorrows of Young Werther" are used to describe the change of their mood. Children at this period begin to have their own thoughts due to their values. Their cognition is more mature. Many psychologists discuss that in the development, the operation of their cognition, They begin to have their own thoughts, and tend to pay more attention to peer relationships, We cannot say that their family has no influence. But during this period, their friends' saying will be more important than that of parents'. Due to these changes of mental state and thoughts, many adults will consider that the children are immature, Naive and unrealistic. Such a description can be heard. It is more important that they can be affected by their friends easily. It is said that "He that touches pitch shall be defiled" Unfortunately, we're usually worried about being defiled than potential positive effect. We hope to keep our children away from naughty ones. They have peer pressure, and under the pressure they will do what we do not expect. In this process, mental shift results in the more negative comments on this stage of children from adults. Consider when you are about 20 or 30 years old, somebody told you that you're such a child. It's mostly not a compliment of your appearance, but reflecting on your immaturity. If it's about the look then be glad. Unfortunately, most of time it means mental immaturity, like a child. It is not a compliment. How about the sociological point of views? How does our society think about this group? Is there "youth" in every country and every culture in the world? Think about the society you live in. Are there youths back in forty, fifty or even a hundred years ago? Have you ever heard a coming-of-age ceremony? What is it? It is a ritual in celebration of one's becoming an adult. Guess at what age do most communities hold a coming-of-age ceremony for a person? Did you guess right? In most social culture, we will hold a coming-of-age ceremony for a person when he is 16 years old. It is called "Genpuku" in Japan, "Chu Hua Yuan" for China's Chaozhou, "make sixteen" in Taiwan. The Jews are even more interesting. For Jews, the coming-of-age ceremony is held when the girl is 12 years old, and the boy is 13 years old. It meets the biological point of views which I just mentioned. When a person's body has the ability to be an adult, which means to raise the next generation, When a man has the ability to give birth to the next generation, we call him an adult. In some societies, as soon as childhood ends, a person enters adulthood. Thus, there is no so-called "youth", so "youth" certainly does not exist. This does not mean that the people in that society will not be thirteen years old, fourteen years old, or eighteen years old. Today, in the same society, Taiwan society, my mother is more than seventy years old, she often says, "There is no youth in our generation," I graduated from primary school when I was twelve, and I had to work to support the family. There were so many people in my family, how could we survive without my work? She didn't have the right to enjoy her youth, Naturally, in the society at that time, it is more impossible for us to hear the youth problem. When there is no "youth", the problem comes nowhere. So in such a process, We will find that there are many different views in the society. From the biology, psychology, to sociology. You will find that "youth" cannot be easily defined. However, when we talk about welfare and rights, we cannot make relevant policies without defining "youth". So in a variety of society, following their cultural values, through their laws, we will define a group of "youth" in laws. Behind this, what we have to think about is the meaning of this law, is the product of the society, built by the society. And most of them are characteristics of industrialized countries. Why do the industrialized countries, the developed countries specially talk about the group of youth, and even let the group exist? Because when a society gets into the process of industrialization, a person's stamina has been far less important than intelligence. People need to be educated. We don't hope them to feed themselves by operating labor. We hope them to learn techniques, so we want children to be educated, learning professional knowledge and techniques, to delay the age of entering the job market. Yet the agricultural society is not, we need stamina to engage in farming, engage in producing. Then sociologists discussed, the youth group was created, the group was created as a unique group, In such a process, we can find that, once a person mature, he will be regarded as an adult in the agricultural society, can enter the labor market, rather than being dependent population. But in industrialized countries, we hope that they can remain in a role of dependent population, be educated, protected, taken care of, and nurtured until they have the ability to enter job market. Also because of this, in many developed countries there are laws defining the age of youth, generally defined as people from twelve to eighteen years old. And in Taiwan, we also use the same age to define the youth. But in the United Nations, we can find an interesting phenomenon. Because every country is in different situations, some are developing, some are developed; some are industry-based, some are business-based, and also some agriculture-based countries, so in United Nations, those who are under eighteen years old are collectively called "children", the United Nations does not have a special term for the youth. In addition, a commonly used term is "teenagers", teenagers are more of spoken language. Is a twenty-year-old person a teenager? Some people consider that, as long as they are still included in dependency population relying on parental support, even undergraduate can be regarded as teenagers. However, since this class involves the welfare system and related policies, the legal definition is also very important. Here I will use the term "youth" to define the group of people who are between 12 and 18 years old, and through this concept to think about how we formulate related services and policies, to respond to their needs, and maintain their rights. It is interesting that, in Taiwan, after a person is 18 years old, he can not be regarded as an adult. Because in our law, a person is regarded as an adult only when he is 20 years old. As careful as you will find that, those who are over 18 years old but less than 20 years old, what are they? They are still called "teenagers", "nineteen", right? But in Taiwan, he is neither a youth nor an adult. This topic is very interesting, I hope everyone can endure toward the last lecture, where I will discuss the issue implied on the convergence of underage and youth, and how we are going to face such a gap.