Can you outsmart the slippery slope fallacy? - Elizabeth Cox

譯者: Lilian Chiu 審譯者: Amanda Zhu

On the plains of the Serengeti, a dung beetle

在賽倫蓋提的平原上，

一隻蜣螂正在滾動 牠塑造的完美糞球，

rolls his perfectly sculpted ball of dung away from competitors.

遠離競爭者。

In this Canadian river, a beaver rushes to reinforce her dam

在加拿大的這條河裡， 一隻海狸正趕去強化牠的水壩，

as it threatens to burst.

因為水壩即將被沖壞。

As the snowball thunders down the mountainside,

當雪球一邊發出巨響一邊滾下山坡，

gaining momentum, the arctic foxes run for cover—

衝力越來越大時， 北極狐跑去找掩護——

I can't stand these nature programs.

我實在受不了這些大自然節目。

Always the same story, and not a rational actor in sight. What else is on?

故事一成不變， 看不到可以講道理的對象。

有什麼其他節目？

It’s April 1954, and Vietnamese nationalists are on the verge of victory

現在是 1954 年 4 月，

越南的民族主義者正為了 爭奪越南的掌控權對抗法國軍隊，

against French forces fighting for control of Vietnam.

他們即將獲得勝利，

Their victory could lead to an independent Vietnam

若他們獲勝，

越南就會在共產黨領導人 胡志明的帶領下獨立。

under communist leader Ho Chi Minh.

The United States President, Dwight D. Eisenhower,

美國總統艾森豪

is holding a press conference to comment on these developments.

召開記者會，說明這些發展。

Well, if you really must.

那，你就說吧。

Eisenhower claims that by virtue of what he calls the “falling domino principle,”

艾森豪聲稱，因為他所謂的

「多米諾骨牌原則」，

communist control of Vietnam would be the “beginning of a disintegration”

越南被共產主義控制就會是

「崩解的開端」，

that would be certain to cause “incalculable loss.”

肯定會造成「無法計算的損失」。

The beetles and beavers may be beyond my reach,

我可能管不了蜣螂和海狸，

but surely here's someone I can reason with.

但我肯定可以跟這個人講道理。

Now, Mr. President, let’s take a deep breath, shall we?

總統先生，

先深呼吸一下，好嗎？

It’s a big leap—or, one might say, a long slide—

你這說法一下跳得太遠了—— 或應該說是滑得太遠了。

from communist governance of Vietnam

從共產黨治理越南

to the global spread of authoritarian communist regimes.

跳到獨裁共產黨政權散播全球。

It’s as if we were to say you were clothed,

這就好像是在說：你本來有穿衣服，

now you’re in your underwear,

現在你只穿內褲，

so soon everyone in the world will be completely naked.

所以很快地，

全世界的人都會全裸。

Don’t worry, I may have that power, but I promise not to use it.

別擔心，也許我有能力讓你們全裸， 但我保證不會這麼做。

Now, as I was saying, this kind of argument,

回到剛才說的，這種論點斷定了

where one step, let’s call it A, kicks off a string of events

一個步驟，姑且稱為 A， 帶出一連串的事件，

that inevitably culminates in an extreme scenario,

最後無可避免地 結束在一個極端的情境，

let’s call it Z, is known as a slippery slope.

姑且稱之為 Z，

這種論點被稱為「滑坡謬誤」。

Many such arguments focus on catastrophe,

許多這類的論點 都把焦點放在大災難上，

but the slope to an extreme positive outcome can be just as slippery.

但導向極端正向結果的斜坡

也可能一樣滑。

The trouble with this kind of argument is that,

這類論點的問題在於，

in presenting Z is the inevitable outcome of A,

它幾乎都會過度誇大 A 發生之後 Z 發生的機率，

it almost always overstates the likelihood that Z will happen

好像 A 必然會導致 Z。

if A happens.

Why?

為什麼？

Allow me to trouble you with some math.

容我用些數學來煩你。

Let’s assume for the sake of argument that, taken individually,

為了方便說理，咱們就假設，

A 和 Z 之間的每一個單獨的步驟

each step between A and Z is independent from the others

都是獨立的，

and very likely— 99%.

且都很可能發生——

都是 99% 的機率。

So the probability that A causes B, that B causes C,

所以，A 造成 B，B 造成 C，

that C causes D, and so on, is each 99%.

C 造成 D 等等，

機率分別都是 99%。

Even so, each additional step adds an opportunity to alter the outcome,

就算如此，

每前進一個步驟，

就會多一個改變結果的機會，

and A is only 78% likely to lead to Z—

因此 A 會導致 Z 的可能性 只有 78%——

far from an inevitability.

離「必然」遠得很。

If there’s a 95% likelihood of each step,

如果每個步驟發生的機率為 95%，

the chance that A leads to Z plummets to about 28%.

A 會導致 Z 的機率

就暴跌到約 28%。

If there’s a 90% likelihood at each step—

如果每個步驟發生的機率為 90%

still very likely by most standards—

——就大部分標準來說， 90% 仍然算「很可能」——

the chance that A leads to Z is only 7%.

A 導致 Z 的機率

就只有 7%。

And if 24 of the 25 steps between A and Z are 99% likely,

如果 A 到 Z 之間的 25 個步驟

有 24 個的發生機率為 99%，

and one is 50% likely,

剩下那一個的機率為 50%，

the chance that A leads to Z

那麼 A 會導致 Z 的機率會再下降，

goes down from 78% to 39%.

從 78% 變成 39%。

Back to your situation.

回到你的情況。

I won’t deny you have reason to be concerned.

我不否認你的擔心其來有自。

You’re warily watching as powerful authoritarian communist regimes

你時時留意著

強大的蘇聯和中國共產主義政權

in the Soviet Union and China try to spread their form of governance.

試圖散播他們的統治形態。

But let’s take a look at the chain of events you suggest:

但，咱們來看看 你提到的一連串事件：

You say that the countries surrounding Vietnam

你說，越南周圍的國家

would all soon fall under communist rule;

很快都會被共產主義統治；

that this would result in a loss of essential trade

這就會導致其他國家 失去和這些國家的重要貿易；

with these countries for others;

that with no non-communist nations left to trade with,

接下來因為沒有 非共產主義國家與之貿易，

Japan would be pressured towards communism

日本會被迫走向共產主義，

and that this, in turn, would threaten Australia and New Zealand.

那接著就會威脅到澳洲

和紐西蘭。

Your ultimate fear, if I may presume,

容我做個假設，你的終極恐懼，

is that this will in turn threaten the United States.

就是接下來美國也會受到威脅。

Is this a possibility? Sure.

有這種可能性嗎？

當然有。

Where I take issue is with your comparison to dominos.

我的異議是針對你用骨牌作的比喻。

These complex real-world events are not, in fact, like dominoes,

其實這些真實世界的事件很複雜，

並不像骨牌——

where when the first one falls,

當第一塊骨牌倒下，

it becomes a certainty that the last will fall.

就可以肯定最後一塊也會倒下。

For any one of these events, a number of possible outcomes could result,

至於你說的這些事件，

每個都有數種可能的結果，

each affecting the other events in different ways.

每個結果都會對其他事件 有不同的影響。

The possibilities are not a chain, they’re a web.

這些機率不是一個接著一個地串連，

而是一張網。

It’s 1975, and after 20 years of conflict, and several million lives lost,

現在是 1975 年，

經過了 20 年的衝突 以及失去了數百萬條生命之後，

North Vietnamese forces have taken control of the capital of South Vietnam.

北越軍隊控制了南越的首都。

The war is over, and all of Vietnam is under communist control.

戰爭結束了，

整個越南都在共產黨的掌控之下。

Communist regimes have come to power in neighboring Laos and Cambodia,

鄰近的寮國和柬埔寨 也都受到共產政權統治，

where the regime will be responsible

估計共產政權造成了

for the deaths of an estimated quarter of all Cambodians.

四分之一柬埔寨人口的死亡。

Wait, there's more.

等等，後面還有。

That first step you were trying to avoid happened,

你試圖避免的第一個 步驟還是發生了，

but the end result you predicted did not.

但你預測的最終結果並沒有發生。

As for the steps between, a few happened; many did not.

至於中間的那些步驟，

有幾個發生了，許多沒有發生。

Decades afterward, your fellow humans are still debating

數十年之後，你的人類同胞還在辯論

why events unfolded the way they did.

事件為什麼是這樣發展的。

And this is the trouble with slippery slope arguments.

這就是「滑坡謬誤」論點的問題：

They focus exclusively on extreme outcomes,

把焦點只放在最極端的結果上，

assigning those outcomes a degree of certainty or inevitability

認定那些極端結果一定會發生

或無可避免，

that rarely corresponds to reality.

但卻很少符合現實狀況。

They divert attention from other, more likely possibilities,

他們把注意力從其他 更可能的結果轉移開來，

foreclosing discussions that might be more productive.

阻擋可能更有成效的討論。

And that’s when they’re made in good faith.

且這還是意圖良善的情況呢。

Slippery slope arguments can also be intentionally structured

滑坡謬誤的論述 也可能是蓄意設計的，

to take advantage of people’s fears—

為的是利用人民的恐懼——

whatever your position on an issue,

不論你對某議題的立場為何，

it’s easy to come up with an extreme outcome that suits your aims.

都很容易找出一個 符合你目標的極端結果。

Best to avoid them entirely, eh?

最好完全避開這種論述，對吧？