Don’t always believe what scientists and other authorities tell you! Be skeptical! Think critically! That’s what I tell my students. Early in my career, I was a conventional science writer, easily impressed by scientists’ claims. But doubt gradually weakened my faith. Scientists and journalists, I realized, by continuously boasting scientific “advances”—from theories of cosmic (宇宙的) creation and the origin of life to the latest treatments for depression and cancer, made science seem more powerful and fast-moving than it really is. Now, I urge my students to doubt the claims of some scientists. This isn’t science anymore; I declare in class, it’s only science fiction with equations! To drive this point home, I assign articles by John Ioannidis, an epidemiologist who has exposed the weakness of most peer-reviewed research. In a 2005 study, he concluded that “most published research findings are false.”

So how do my students respond to my skeptical teaching? Some react with healthy pushback, especially to my suggestion that the era of really big scientific discoveries might be over. “On a scale from toddler knowledge to ultimate enlightenment, man’s understanding of the universe could be anywhere,” wrote a student named Matt. “How can a person say with certainty that everything is known or close to being known if it is incomparable to anything?”

Other students embrace skepticism to a degree that shocks me. Cecelia, a biomedical-engineering major, wrote: “I am skeptical of the methods used to collect data on climate change, the analysis of this data, and the predictions made based on this data.” Pondering (思索) the lesson that correlation does not equal causation, Steve questioned the foundations of scientific reasoning. “How do we know there is a cause for anything?” he asked.

In a similar way, some students echoed the claim of radical (激进的) postmodernists that we can never really know anything for certain, and hence that almost all our current theories will probably be overturned. Just as Aristotle’s physics gave way to Newton’s, which in turn yielded to Einstein’s, so our current theories of physics will surely be replaced by completely different ones.

After one especially harsh paper, I responded, “Whoa!” Science, I lectured sternly, has established many facts about reality beyond a reasonable doubt, embodied by quantum mechanics, general relativity, the theory of evolution, the genetic code. This knowledge has yielded applications—from vaccines to computer chips—that have transformed our world in countless ways. It is precisely because science is such a powerful mode of knowledge, I said, that you must treat new pronouncements skeptically, carefully distinguishing the genuine from the false. But you shouldn’t be so skeptical that you deny the possibility of achieving any knowledge at all.

My students listened politely, but I could see the doubt in their eyes. We professors have a duty to teach our students to be skeptical. But we also have to accept that, if we do our jobs well, their skepticism may turn on us.

Knowing that you are paid less than your peers (同龄人) has two effects on happiness. The well-known one is negative (消极的): a thinner pay packet harms self-respect. The less-known one is called the “tunnel” (隧道) effect: high incomes for peers are seen as improving your own chances of similar riches.

A study by professor Mr. Fitzroy separates the two effects using data from household surveys in Germany. Previous work showed that the income of others can have a small, or even positive effect on people's satisfaction. But Mr. Fitzroy’s team theorized that older workers, who largely know their lifetime incomes already, will enjoy a much smaller tunnel effect.

The data confirm this view. The negative effect on reported levels of happiness of being paid less than your peers is not obvious for people aged under 45. Seeing peers' incomes rising actually makes young people happier (even more than a rise in their own incomes). It is only those people over 45, when careers have “reached a stable position”, whose happiness is harmed by the success of others.

Those with jobs are no happier after they retire, however, perhaps because their lives already line up with social expectations. Indeed, retiring early from work can have side effects. Men retiring a year early lower their possibility of surviving to age 67 by 13%. Almost a third of this higher death rate, which seemed to be concentrated among those who were forced into retirement by job loss, was caused by drug and alcohol addiction.

So a person's value does not only depend on how much they buy material goods and recreations but is also influenced by how well a person obeys the generally accepted standards of social behaviour of the category he belongs to. Applying identity theory to the relationship between unemployment and life satisfaction implies that unemployed people are not only dissatisfied with their life because they have lower incomes, but also because they don’t follow the standards of their social category under which they are expected to work.

Acting is such an over-crowded profession that the only advice that should be given to a young person thinking of going on the stage is “Don’t!”. But it is useless to try to discourage someone who feels that he must act, though the chances of his becoming famous are slim. The normal way to begin is to go to a drama school. Usually only students who show promise and talent are accepted, and the course lasts two years. Then the young actor or actress takes up work with a repertory company, usually as an assistant stage manager. This means doing everything that there is to do in the theatre: painting scenery, looking after the furniture, taking care of the costumes, and even acting in very small parts. It is very hard work indeed. The hours are long and the salary is tiny. But young actors with the stage in their blood are happy, waiting for the chances of working with a better company, or perhaps in films or television.

Of course, some people have unusual chances which lead to fame and success without this long and dull training. Connie Pratt, for example, was just an ordinary girl working in a bicycle factory. A film producer happened to catch sight of her one morning waiting at a bus stop, as he drove past in his big car. He told the driver to stop, and he got out to speak to the girl. He asked her if she would like to go to the film studio to do a test, and at first she thought he was joking. Then she got angry and said she would call the police. It took the producer twenty minutes to tell Connie that he was serious. Then an appointment was made for her to go to the studio the next day. The test was successful. They gave her some necessary lessons and within a few weeks she was playing the leading part opposite one of the most famous actors of the day. Of Course, she was given a more dramatic name, which is now world-famous. But chances like this happen once in a blue moon!