雙語閱讀｜照明經濟學

Back in the mid-1990s, an economist called William Nordhaus conducted a series of simple experiments with light.

20世紀90年代中期，一位名叫威廉·諾德豪斯（William Nordhaus）的經濟學家用光線做一些簡單的實驗。

First, he used a prehistoric technology: he lit a wood fire. But Prof Nordhaus also had a piece of hi-tech equipment with him - a Minolta light meter.

他先用了最古老的技術：點燃木柴。不過，諾德豪斯教授也使用了一件高科技設備——美能達測光表。

He burned 20lb (9kg) of wood, kept track of how long it burned for and carefully recorded the dim, flickering firelight with his meter.

他燃燒了一塊九公斤重的木頭，記下燃燒完花的時間，用測光表仔細測量木柴燃燒發出的昏暗、閃爍的火光，並記好錄下來。

Next, he bought a Roman oil lamp, fitted it with a wick, and filled it with cold-pressed sesame oil. He lit the lamp and watched the oil burn down, again using the light meter to measure its soft, even glow.

接下來，他買了一盞古羅馬油燈，裝上一根燈芯，倒滿冷榨芝麻油。他點燃燈，觀察燈油燃燒，再次用測光表測量油燈發出的柔軟均勻的燈光。

Bill Nordhaus's open wood fire had burned for just three hours on 9kg of wood. But a mere eggcup of oil burned all day, and more brightly and controllably.

僅用了三小時，威廉·諾德豪斯在露天里燒光了整整九公斤木材。不過，一小蛋杯的燈油卻可以燃燒一整天，光線也更加明亮和可控。

Why did he do this? He wanted to understand the economic significance of the light bulb.But Prof Nordhaus also wanted to illuminate a difficult issue for economists: how to keep track of inflation, the changing cost of goods and services.

諾德豪斯教授為什麼要做這樣一個實驗？一方面，他想了解電燈泡的經濟學意義。另一方面，他也想藉此啟發經濟學家解決另一個難題，即：如何監控通貨膨脹，跟蹤貨品和服務成本的變化。

To see why this is difficult, consider the price of travelling from - say - Lisbon in Portugal to Luanda in Angola. When that journey was first made, by Portuguese explorers, it would have been an epic expedition, possibly taking months.Later, by steam ship, it would have taken a few days; then, by plane, a few hours.

這個問題究竟為何難以解決，不妨看看從葡萄牙里斯本到安哥拉羅安達的交通費用。當葡萄牙探險家首次踏上這趟旅程時，這還是一場史詩般的探險活動，可能要花費數月時間。後來，蒸汽船將旅程縮短至幾天； 再後來，乘飛機幾個小時就能到達目的地。

An economic historian could start by tracking the price of passage on the ship, but once an air route has opened up, which price do you look at?

一個經濟史學家一開始是跟蹤船票價格，但是，一旦航空線路開通，你會關注哪裡個的運輸成本呢？

Maybe you simply switch to the airline ticket price once more people start flying than sailing.

當越來越多的人不坐船，改坐飛機時，交通費用或許可以按機票價格計算。

But flying is a different service - faster, more convenient.

可是，坐飛機與坐船是完全不同的服務——坐飛機相對更加方便快捷。

If more travellers are willing to pay twice as much to fly, it hardly makes sense for inflation statistics to record that the cost of the journey has suddenly doubled.

如果更多的旅客願意多花一倍的錢坐飛機，那麼通貨膨脹統計數據顯示旅程交通費突然翻倍就說不通了。

It was to raise this question over the way we measure inflation that Bill Nordhaus started fooling around with wood fires, oil lamps and light meters.

正因為諾德豪斯想讓人們在測量通貨膨脹的過程中提出這個問題，因此他才開始拿木柴，油燈和測光表做實驗。

He wanted to unbundle the cost of a single quality that humans have cared deeply about since time immemorial, using the state-of-the-art technology of different ages: illumination.

他希望通過不同歷史階段的照明技術，將人類自古以來就十分關心的單一質量成本進行拆分計算。

Light is measured in lumens, or lumen-hours. A candle gives off 13 lumens while it burns. A typical modern light bulb is almost 100 times brighter than that.

光以流明或流明時間為測量單位。蠟燭燃燒時的光度為13流明。一個現代典型電燈泡的亮度是蠟燭的將近一百倍。

Imagine gathering and chopping wood 10 hours a day for six days. Those 60 hours of work would produce 1,000 lumen hours of light.

想象一下，連續6天，每天收集和砍伐木材10小時。這60小時的工作將產生1000流明小時的光線。

That is the equivalent of one modern light bulb shining for just 54 minutes, although what you would actually get is many more hours of dim, flickering light instead.

一個現代電燈泡僅用54分鐘就能發出這麼多光，雖然時間變短了，光線卻更明亮和穩定。

Of course, light is not the only reason to burn fires: they also help keep you warm, cook your food and scare off wild animals.

當然，火堆的作用不僅在於照明，它還可以用來取暖，烹飪食物，嚇跑其他野生動物以自衛。

If you just needed light and a wood fire was your only option, you might decide to wait until the Sun comes up.

如果只是需要光，而生火又是唯一的選擇，還不如直接等太陽升起來。

Thousands of years ago, better options came along - candles from Egypt and Crete, and oil lamps from Babylon. Their light was steadier and more controllable, but still prohibitively expensive.

數千年前，埃及和克里特島的蠟燭，巴比倫的油燈，取代火成為了人們照明的更優選擇。蠟燭和油燈的光線更穩定，更可控，卻仍然昂貴無比。

In a diary entry of May 1743, the president of Harvard University, the Reverend Edward Holyoake, noted that his household had spent two days making 78lb (35kg) of tallow candles.

1743年5月，哈佛大學校長愛德華·霍洛伊克（Edward Holyoake）在日記中寫到，他全家花了兩天時間製作了78磅（35公斤）的豬油蠟燭。

Six months later, he noted: "Candles all gone." And those were the summer months.

六個月後，他寫道：「所用蠟燭都用完了。」 那還僅是夏季幾個月的消耗量。

Nor were these the clean-burning paraffin wax candles we use today.

而直到今天，我們使用的石蠟蠟燭燃燒時仍會污染環境。

The wealthiest could afford beeswax, but most people - even the Harvard president - used tallow candles, stinking, smoking sticks of animal fat. Making them involved heating up animal fat and dipping and re-dipping wicks into the molten lard.It was pungent and time-consuming work.

有錢人買得起蜂蠟，但是，大多數人——即使是哈佛大學校長——用的還是動物脂肪做的、刺鼻、冒煙的普通蠟燭。 製作這樣的蠟燭要燒化動物脂肪，並將蠟燭芯反覆浸入熔化的豬油中。過程中產生的味道十分刺鼻，工序十分耗時。

According to Prof Nordhaus's research, if you set aside one whole week a year to spend 60 hours devoted exclusively to making candles - or earning the money to buy them - that would enable you to burn a single candle for just two hours and 20 minutes every evening.

根據諾德豪斯教授的研究結果，如果一個人每年用一整周60個小時的時間專門做蠟燭，或者賺錢買足夠的蠟燭，就能夠每晚用蠟燭照明2小時20分鐘。

Things improved a little as the 18th and 19th Centuries unfolded. Candles were made of spermaceti - the milk-hued oily gloop harvested from dead sperm whales.

十八，十九世紀后，照明技術有所改善。人們開始用鯨油制蠟——抹香鯨巨大的頭部骨腔內含有大量鯨腦油，可以用來製作鯨蠟。

American founding father Ben Franklin loved the strong, white light they gave off, and the way they "may be held in the hand, even in hot weather, without softening", and noted that they "last much longer".

美國國父本·富蘭克林（Ben Franklin）非常喜愛鯨蠟燃燒時放出的明亮白光。他曾指出，鯨蠟「即使在炎熱的天氣中握在手裡也不會融化」，而且「燃燒時間更長」。

While the new candles were pleasing, they were also pricey.

雖然新蠟燭很好，還是很貴。

George Washington calculated that burning a single spermaceti candle for five hours a night all year would cost him £8, or well over $1,000 (£820) in today's money.

喬治·華盛頓曾計算，當時每晚點一支鯨蠟五個小時，一年下來將花費8英鎊，相當於今天的1000美元（約合人民幣7000元）。

A few decades later, gas lamps and kerosene lamps helped to lower costs. They also saved the sperm whale from extinction.

幾十年後，燃氣燈和煤油燈的出現再次降低了照明成本。它們也拯救了瀕臨滅絕的抹香鯨。

But they, too, were basically an expensive hassle.They dripped, smelt and set fire to things.

可是，它們也不便宜，還很麻煩。不僅會滴油，味道刺鼻，還引燃其他物品。

Then something changed.That something was the light bulb.

然後，真正的改變發生了。電燈泡出現了。

By 1900, one of Thomas Edison's carbon filament bulbs would provide you with 10 days of bright, continuous illumination, 100 times as bright as a candle, for the money you could earn with our 60-hour week of hard labour.

到1900年，一個人每周工作60小時賺取的錢，可以換來托馬斯·愛迪生發明的碳絲燈泡提供的10天連續照明，照明強度是蠟燭的100倍。

By 1920, that same week of labour would pay for more than five months' continuous light from tungsten filament bulbs. By 1990, it was 10 years. A couple of years after that, thanks to compact fluorescent bulbs, it was more than five times longer.

1920年，相同的勞動所得可以支付起鎢絲燈泡5個多月的連續照明。1990年，5個月變成了10年。幾年之後，緊湊型熒光燈泡又把這個時間提升了五倍以上。

The labour that had once produced the equivalent of 54 minutes of quality light now produced 52 years.

相同的勞動，曾經只能帶來54分鐘的標準強度照明，現在卻能夠帶來52年的標準強度照明。

And modern LED lights continue to get cheaper and cheaper.

現在，LED燈照明變得越來越便宜。

Switch off a light bulb for an hour and you are saving illumination that would have cost our ancestors all week to create. It would have taken Benjamin Franklin's contemporaries all afternoon. But someone in a rich industrial economy today could earn the money to buy that illumination in a fraction of a second.

關閉一個燈泡一個小時，省下來的流明相當於人類祖先耗費一周創造的流明。即使在本傑明·富蘭克林的時代，也要等於一個下午的時間。如今，在發達工業經濟體中，一個人僅工作幾分之一秒就能買到1小時的照明。

And of course, unlike oil lamps and candles, modern light bulbs are clean, fire-safe and controllable.

當然，與油燈和蠟燭不同，現代燈泡清潔，防火，可控。

The light bulb has become an icon of innovation. It has transformed our society into one where we can work, read, sew or play whenever we want to, regardless of how dark the night has become.

燈泡成為創新的標誌。 這讓人類社獲得了巨大的進步，即使在漆黑的夜裡，人們也可以正常工作，閱讀，縫縫補補和消遣娛樂。

But the price of light alone tells a fascinating story: it has fallen by a factor of 500,000, far faster than official inflation statistics suggest.

照明成本的變化本身就是個十分傳奇的故事：它至今減少了50萬倍，遠遠大於官方計算出的通貨膨脹的速度。

A thing that was once too precious to use is now too cheap to notice.

照明，這一曾經無比珍貴的東西，現在已經便宜得甚至讓人感覺不到在為它花錢了。

英文來源：BBC

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