Our perception that inflation is the normal condition is no more than a reflection of the experience of people alive today. In 1913, unlike now, a pound or a dollar would have bought the same goods as a century earlier. The longest semi-official price series we have reports a 140 fold rise in prices in the UK since 1750 — but even then all the increase up to 1938 is accounted for by inflation during the Napoleonic and first world wars. Indeed, while the price level roughly doubled during both these episodes, it fell slightly over the rest of the period.
我们对于通胀是常态的观念，只是反映了当今在世的人们的经验。不同于现在，1913年时1英镑或1美元能够买到与一个世纪前同样的商品。我们拥有的最长的半官方价格序列显示，自1750年以来英国物价上涨了140倍，但即便如此，截至1938年的所有上涨均可归因于拿破仑战争以及第一次世界大战期间的通胀。的确，尽管物价水平在这两次战争期间大致都翻了一番，但在其他时期略有下降。

This historical perspective may offer a partial antidote to the fears of investors over the arrival of deflation in Europe, where a euro today buys more than a year ago. But there are other reasons not to panic. For one, there is no qualitative difference between an economy in which prices are rising slightly and one in which prices are falling slightly. Unlike water, liquid at temperatures above 0C and solid below, the consumer price index is a complex statistical construct not a physical fact. You can see and feel the difference between ice and water, and you can skate on one but not the other. Similarly, with a commodity such as petrol, you can tell whether the price at the pump is rising or falling because petrol is a homogeneous product that changes little over time.
这一历史视角可能在一定程度上缓解投资者对于通缩降临欧洲的担忧，如今1欧元在欧洲的购买力已超过1年前的水平。但还有其他理由让人们不必恐慌。首先，物价缓慢上涨与物价缓慢下跌的两个经济体之间没有本质区别。与水（0摄氏度以上为液体，以下为固体）不同，消费者价格指数(CPI)是一个复杂的统计模型，而非物理事实。你可以看到并感觉到冰与水的不同，而且冰上可以滑行，水上不行。同样地，对于汽油这类商品，你可以在加油站看出其价格是升还是降，因为汽油是一种随时间推移变化很小的同质产品。
But what has been happening with cars, or smartphones, or medical services? In the CPI, the price component for cars comprises the sticker price adjusted for changes in quality. Such quality adjustment is subjective — and, it is generally conceded, too low. So we could have been experiencing deflation for years without realising it.
但是，汽车、智能手机或是医疗服务发生了什么变化呢？在消费者价格指数中，汽车价格构成中包括根据品质变化而调整的标牌价格。此类品质调整是主观的，而且被普遍认为太低。因此，我们可能多年经历通缩，但对它毫无察觉。
Moreover, the surface of a pond will be cold enough to skate on when the average temperature of the whole pond (ice on the surface and water beneath) is well above zero. With a good deal of effort you could compute the average temperature of the entire contents of the pond. But the answer will not tell you whether it is safe to skate.
此外，当整个水池（表面是冰，下面为水）的平均气温高于0摄氏度时，水池表面的温度可能冷到可以滑行。你如果煞费苦心，可以计算出水池全部水体的平均温度。但这一答案不会告诉你在结冰的表面滑冰是否安全。
The central point is that the significance of a fall in a price index depends on the causes of that fall. The declining price level in the second half of the 19th century was the result of rising manufacturing productivity and the opening up of new lands, particularly in North America. Global grain prices tumbled from the end of the US civil war until the 1890s. This raised real industrial incomes in more advanced economies but also reduced agricultural rents — the beginning of the end for the Old World’s landed aristocracy. The 19th century technological developments and shifts in global trade patterns have obvious parallels today in the development of a digital economy and the rise of China, which have similarly contributed to the fall in the inflation rate since 1980.
问题的核心在于，价格指数下降的重要性取决于下降的原因。19世纪后半叶物价水平的下跌是制造业生产率提高以及新增开垦土地（尤其是在北美）的结果。全球谷物价格从美国内战结束至1890年代一直在下跌。这既提高了更发达经济体的实际工业收入，也减少了农业租金——旧世界的土地贵族由此开始走向衰亡。19世纪的科技进步和全球贸易格局变化，与当今数字经济的发展以及中国的崛起明显相似，后两者促进了自1980年以来通胀率的下降。
On the other hand the deflation, and the associated depression and social strife, that Britain experienced between the world wars was largely the result of a misguided attempt to restore the 1914 exchange rate against the dollar. Prices in Britain fell steadily after 1920 until President Franklin Roosevelt finally wrecked the gold standard at the London Conference on exchange rate stabilisation in 1933.
另一方面，英国在两次世界大战间隔期间所经历的通缩（以及伴随而来的萧条和社会冲突），主要是一项旨在恢复1914年时英镑/美元汇率的误入歧途的尝试所致。英国的物价在1920之后不断下降，直至美国总统富兰克林•罗斯福(Franklin Roosevelt)最终在1933年讨论汇率稳定的伦敦会议上破坏了金本位制。
This dismal economic policy and economic performance finds modern parallels, too — here, in the travails of the eurozone. Falling prices have often been associated with economic transformations or recessions; but, contrary to the fears and hopes of investors, price deflation is the effect rather than the cause.
这种糟糕的经济政策和经济表现在现代也有影子，欧元区的艰难处境就是一例。物价下跌往往伴随着经济转型或衰退；但与投资者的担忧和希望相反，物价下跌是结果，而非原因。
The development that is tipping western economies into “deflation”, defined as a negative year-on-year change in CPI, is the fall in energy prices, which is good news for importing countries.
导致西方经济体进入“通缩”（消费者价格指数同比负增长）的事态是能源价格的下降，但这对能源进口国是个好消息。
Raised body temperature might be a sign of fever or the result of a relaxing hot bath: it is wise to determine which it is before you start to worry, far less prescribe remedies.
体温升高可能是发烧的征兆，也可能是洗了一个让人放松的热水澡的结果：在开始担忧之前先确定原因是明智的，而急着开处方补救是不可取的。