单词本：decimate

Yuval Noah Harari 的《人类简史》(Sapiens: A Brief History of Humankind 2014) 中谈及货币的产生过程以及以物易物时代。设想一个场景，如果因为疫情，牲畜大量病死，皮草就变得稀少，这时候怎么设定定价物就不容易了。

Besides, in recent weeks a disease has decimated the focks around town, and skins are becoming scarce.

这里， decimate 是大肆杀戮的意思。而 decimate 看起来和 decimal 很像，而 decimal 则是十进制，源于拉丁语 decimalis 。而 decimus是第十的意思， decem 则是十的意思。

那么，为什么 decimate 是大肆杀戮呢？

原来古罗马对叛军或征服的城市会实施 decimatus 惩罚。而 decimatus 就是说是个人里面要找出一个人杀掉，即十抽一杀掉。

所以， decimate 的几个意思，都和十抽一相关：

• 从十个里抽一个，本意。
• 大批杀死、大量毁灭。这是后来传播的时候对十抽一杀死的误解，变而成为大量杀死。其实本意是少量杀死么。
• 征收。这可能和古代的十一税有关，即十份收成征收一份税。

比如：

• In the New World, European colonists initially enslaved Native Americans, decimating the indigenous(土生土长的) populations to one-tenth(这里说欧洲殖民者屠杀了9/10的土著，远远超过了 decimate 十抽一屠杀的数量。所以这里 decimate 就是大批杀死的意思) of their original sizes.
• African slaves were needed to replace Native American populations that had been decimated (literally reduced to one-tenth their size) by European conquest.

再比如，美国有个Section 230法案，It is a law that protects online platforms from liability for user posts and moderation decisions. 最近有讨论要废弃这个法案，意味着小的在线企业要支付大笔法律顾问费用。所以有新闻这么写：

Sunsetting Competition: Scraping Section 230 Would Decimate Small Tech, Discourage Free Speech Online ¹

这里 decimate 指的是会消灭大批小技术企业。

Israel and Hamas have been entrenched in a deadly war since that has decimated Gaza; more than 34,500 Palestinians have been killed, per the AP, and more than 1,700 people in Israel have been killed, per ABC News. – Michael Saponara, Billboard, 7 May 2024

这里说以色列哈马斯战争导致加沙地区人口大量死亡。

另外，我们还要区分 annihilate 和 decimate 的区别。正如前面说的， decimate 是一种十抽一的惩罚机制，所以不是完全消灭。而 annihilate 则是完全消灭，完全歼灭的意思。注意区分两者的区别。

比如 annihilate 往往后面跟着 entire 或 all，表示完全消灭。

• The bomb was powerful enough to annihilate the entire city.
• The disease threatened to annihilate the entire population.
• The army was ordered to annihilate the enemy forces.

而 decimate 往往跟着消灭数量的比例：

• The hurricane decimated the coastal town, leaving only 10% of the buildings standing.
• The virus decimated the population, killing 50% of the infected individuals.
• The economic crisis decimated the company’s profits, reducing them by 90%.

另外，在统计学和信号采样技术中，有个术语叫 decimate ，它的意思是下采样（ downsampling ），或者说是减少采样点，比如，我们可以在 R语言里调用这个函数进行下采样，蓝色线条就是 decimate 之后的效果：

# install.packages('signal', repos = "http://cran.r-project.org")
library('signal')
t <- seq(0, 2, by = 0.01)
x <- chirp(t, 2, 0.5, 10, 'quadratic') + sin(2*pi*t*0.4)
y <- decimate(x, 4)   # factor of 4 decimation
plot(t, x, type = "l")
lines(t[seq(1, length(t), by = 4)], y, col = "blue")

还有，当时罗马人十个里面杀一个叛徒或俘虏，是通过抽签决定的。抽签 draw lots或 by lot。比如

• If no one volunteers to be the club’s secretary, then we’ll have to pick someone by lot.
• We drew lots to decide who would go.
• Competitors draw lots to see who gets which boat.
• We drew lots to decide the order in which we would perform.
• He suggested drawing lots for the best seats.
• There were only two beds, so we drew lots to decide who would get them.

在英语里，也常说pick out of hat,或 a name from a hat, taken from a hat 表示抽签。也许是因为古时候人人都会戴一顶帽子，帽子就能代替人了。

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