因为最近的新型肺炎，下了这本书来读，说的是十九二十世纪有了近现代医学以后的传播性疾病。比起中古时候一死死掉一个帝国三分之一人口那种程度的瘟疫，近代情况是好得多了；那时候时不时来一场瘟疫简直是自然常用控制人口的手段：
In A.D. 165, the Roman Empire was devastated by an epidemic now believed to have been smallpox. The pestilence raged for fifteen years, claiming victims in all social strata in such high numbers that some parts of the Roman empire lost 25 to 35 percent of their people.
The Coming Plague
记得以前看的一本说中世纪医生怎么看病的，随手就开奇奇怪怪的毒当药，一次几百毫升地放血，还不好，行，继续放；然后想，怪不得那时候老年人地位高，世道这么艰难，能活个三四十岁已经很了不起了，谁真能活到七老八十，那不得当仙人供起来吗？
书看下来每次故事都类似：
先是病毒基因变异，或者因为生态环境突然改变某种动物失衡增长发病，从不卫生的地方开始滋生，人们的恐慌逃难导致疾病散播，总是第一道防线护士医生先传染。现在科技是更发达没错，可是恐慌谣言与人口流动的速度也发达了许多；抗生素是更多没错，但是各行各业的滥用造成抗药病原也越来越普遍。。
最终未来是更好了吗？我也不知道。
书看得我有点抑郁，于是回头翻了一下前段时间看的 Enlightenment Now：
The nature of news is likely to distort people’s view of the world because of a mental bug that the psychologists Amos Tversky and Daniel Kahneman called the Availability heuristic: people estimate the probability of an event or the frequency of a kind of thing by the ease with which instances come to mind. In many walks of life this is a serviceable rule of thumb. Frequent events leave stronger memory traces, so stronger memories generally indicate more-frequent events: you really are on solid ground in guessing that pigeons are more common in cities than orioles, even though you’re drawing on your memory of encountering them rather than on a bird census. But whenever a memory turns up high in the result list of the mind’s search engine for reasons other than frequency—because it is recent, vivid, gory, distinctive, or upsetting—people will overestimate how likely it is in the world.
The consequences of negative news are themselves negative. Far from being better informed, heavy newswatchers can become miscalibrated. They worry more about crime, even when rates are falling, and sometimes they part company with reality altogether: a 2016 poll found that a large majority of Americans follow news about ISIS closely, and 77 percent agreed that “Islamic militants operating in Syria and Iraq pose a serious threat to the existence or survival of the United States,” a belief that is nothing short of delusional. Consumers of negative news, not surprisingly, become glum: a recent literature review cited “misperception of risk, anxiety, lower mood levels, learned helplessness, contempt and hostility towards others, desensitization, and in some cases, . . . complete avoidance of the news.” And they become fatalistic, saying things like “Why should I vote? It’s not gonna help,” or “I could donate money, but there’s just gonna be another kid who’s starving next week.”
The nonmonotonicity of social data provides an easy formula for news outlets to accentuate the negative. If you ignore all the years in which an indicator of some problem declines, and report every uptick (since, after all, it’s “news”), readers will come away with the impression that life is getting worse and worse even as it gets better and better. In the first six months of 2016 the New York Times pulled this trick three times, with figures for suicide, longevity, and automobile fatalities.
Enlightenment Now
越是在漩涡中央的人，才该在做好防御工作的同时少看新闻啊，恐慌和焦虑对免疫力是有实在影响的。