On the basis of cultural relativism, the values of artistic works are simply reflections of local social and economic conditions. Such a view, however, fails to explain the ability of some works of art to excite the human mind across cultures and through centuries.

    History has seen the endless productions of Shakespearean plays in every major language of the world. It is never rare to find that Mozart packs Japanese concert halls, as Japanese painter Hiroshige does Paris galleries. Unique works of this kind are different from today's popular art, even if they began as works of popular art. They have set themselves apart in their timeless appeal and will probably be enjoyed for centuries into the future.

    In a 1757 essay, the philosopher David Hume argued that because “the general principles of taste are uniform(不变的) in human nature, “the value of some works of art might be essentially permanent. He observed that Homer was still admired after two thousand years. Works of this type, he believed, spoke to deep and unvarying features of human nature and could continue to exist over centuries.

    Now researchers are applying scientific methods to the study of the universality of art. For example, evolutionary psychology is being used by literary scholars to explain the long-lasting themes and plot devices in fiction. The structures of musical pieces are now open to experimental analysis as never before. Research findings seem to indicate that the creation by a great artist is as permanent an achievement as the discovery by a great scientist.

    A little old couple walked slowly into McDonald's one cold winter evening. They were so old that they looked out of place among the young families and young couples eating there that night.

    Some of the customers looked admiringly at them. You could tell what the admirers were thinking. “Look, there is a couple who has been through a lot together, probably for 60 years or more!”

    The little old man walked right up to the cash register (收银台), placed his order with no hesitation and then paid for their meal. The couple took a table near the back wall and started taking food off the tray (托盘). There was one hamburger, one order of French fries and one drink. The little old man unwrapped the plain hamburger and carefully cut it in half. He placed one half in front of his wife. Then he carefully counted out the French fries, divided them in two piles and neatly placed one pile in front of his wife. He took a sip of the drink, his wife took a sip and then set the cup down between them.

    As the man began to eat his few bites of hamburger the crowd began to get restless. Again you could tell what they were thinking, “That poor old couple. All they can afford is one meal for the two of them.”

    As the man began to eat his French fries one young man stood and came over to the old couple's table. He politely offered to buy another meal for the old couple to eat. The old man replied that they were just fine. They were used to sharing everything.

    Then the crowd noticed that the little old lady hadn't eaten a bite. She just sat there watching her husband eat and occasionally taking turns sipping the drink.

    Again the young man came over and begged them to let him buy them something to eat. This time the lady explained that, no, they were used to sharing everything together.

    As the little old man finished eating and was wiping his face neatly with a napkin the young man could stand it no longer. Again he came over to their table and offered to buy some food.

    After being politely refused again, he finally asked a question of the little old lady. “Ma'am, why aren't you eating? You said that you share everything. What is it that you are waiting for?”

    She answered, “The teeth”.

    Persuasion is the art of convincing someone to agree with you. According to the ancient Greeks, there are three basic tools of persuasion: ethos, pathos, and logos.

    Ethos is a speaker's way of convincing the audience that she is trustworthy, honest and reliable. One common way a speaker can develop ethos is by explaining how much experience or education she has in the field. After all, you're more likely to listen to advice about how to take care of your teeth from a dentist than a fireman. A speaker can also create ethos by convincing the audience that she is a good person. If an audience cannot trust you, you will not be able to persuade them.

    Pathos is a speaker's way of connecting with an audience's emotions. For example, a politician who is trying to convince an audience to vote for him might say that he alone can save the country from a terrible war. These words are intended to fill the audience with fear, thus making them support him. Similarly, an animal charity might show an audience pictures of injured dogs and cats, to make the viewers feel pity. If the audience feels bad for the animals, they will be more likely to donate money.

    Logos is the use of facts, statistics, or other evidence to support your argument. An audience will be more likely to believe you if you have convincing data to back up your claims. Presenting this evidence is much more persuasive than simply saying "believe me".

    Although ethos, pathos, and logos all have their strengths, they are often most effective when used together. Indeed, most speakers use a combination of ethos, pathos, and logos to persuade their audiences. So, the next time you listen to a speech, watch a commercial, or listen to a friend try to convince you to lend him some money, be on the lookout for these ancient Greek tools of persuasion.

    Many people spend more than four hours per day on We Chat, and it is redefining the word “friend.” Does friending someone on social media make him or her your friend in real life?

    Robin Dunbar, a professor at Oxford University, found that only 15, of the 150 Facebook friends the average user has, could be counted as actual friends and only five as close friends. We Chat may show a similar pattern.

    Those with whom you attended a course together, applied for the same part-time job, went to a party and intended to cooperate but failed take up most of your WeChat friends. In chat records, the only message may be a system notice, “You have accepted somebody's friend request”. Sometimes when seeing some photos shared on “Moments”, you even need several minutes to think about when you became friends. Also, you may be disturbed by mass messages (群发信息) sent from your unfamiliar “friends”, including requests for voting for their children or friends, links from Pinduoduo.com (a Chinese e-commerce platform that allows users to buy items at lower prices if they purchase in groups) and cookie-cutter (千篇一律的) blessings in holidays.

    You would have thought about deleting this type of “friends” and sort out your connections. But actually you did not do that as you were taught that social networking is valuable to one's success. Besides, it would be really awkward if they found that you have unfriended them already. Then, you keep increasing your “friends” in social media and click “like” on some pictures that you are not really interested. But the fact is that deep emotional connections do not come with the increasing number of your friends in social media.

    If the number of your friends reaches 150, maintaining these relationships can be tough to you, and sometimes even will make you anxious. According to Robin Dunbar, 150 is the limit of the number of people with whom one can maintain stable social relationships.