Can you solve the rebel supplies riddle? - Alex Gendler

2,835,766 views ・ 2018-09-10

TED-Ed


请双击下面的英文字幕来播放视频。

翻译人员: Christina Wang 校对人员: Lipeng Chen
00:06
You’re overseeing the delivery of crucial supplies to a rebel base
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你正在监管关键物资 到反叛基地的运送,
00:11
deep in the heart of enemy territory.
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基地位于敌军营地的深处。
00:14
To get past Imperial customs, all packages must follow a strict protocol:
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若要通过帝国海关,所有包裹 必须严格遵循一条规定:
00:19
if a box is marked with an even number on the bottom,
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如果一个箱子的底部标有一个偶数,
00:23
it must be sealed with a red top.
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那么它的顶部必须是红色的封口。
00:27
The boxes are already being loaded onto the transport
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正当箱子在被放到运输工具上时,
00:30
when you receive an urgent message.
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你收到了一条紧急消息。
00:32
One of the four boxes was sealed incorrectly,
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四个箱子中的一个 封装是不正确的,
00:36
but they lost track of which one.
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但他们不知道是哪一个。
00:38
All the boxes are still on the conveyor belt.
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所有的箱子都还在传送带上。
00:41
Two are facing down: one marked with a four,
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两个是朝下放的:一个标着 4,
00:45
and one with a seven.
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一个标着 7.
00:46
The other two are facing up:
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另外两个是朝上放置的:
00:48
one with a black top,
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一个的顶部是黑色的,
00:49
another with a red one.
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另一个是红色的。
00:52
You know that any violation of the protocol
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你知道任何规定违反
00:54
will get the entire shipment confiscated and put your allies in grave danger.
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会导致整皮货物被没收, 让盟友陷入危险。
01:00
But any boxes you pull off for inspection won’t make it onto this delivery run,
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但任何你拿下来检查的箱子 就赶不上这次运输了,
01:05
depriving the rebels of critically needed supplies.
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致使反叛军无法得到急需的物资。
01:09
The transport leaves in a few moments, with or without its cargo.
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运输工具马上就要离开了, 无论是否有货物。
01:13
Which box or boxes should you grab off the conveyor belt?
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那你应该从传送带取下来 哪个或哪几个箱子?
01:18
Pause the video now if you want to figure it out for yourself!
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如果你想自己搞清答案 就在这里暂停视频!
01:23
Answer in: 3
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答案即将公布:3
01:25
Answer in: 2
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答案即将公布:2
01:26
Answer in: 1
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答案即将公布:1
01:27
It may seem like you need to inspect all four boxes
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你可能觉得你需要拿走全部4个箱子
01:31
to see what’s on the other side of each.
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以检查另外一面的内容。
01:33
But in fact, only two of them matter.
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但其实,你只需要看两个箱子。
01:36
Let’s look at the protocol again.
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让我们回顾一下规定。
01:38
All it says is that even-numbered boxes must have a red top.
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它只说了偶数箱子 必须要有红色封顶。
01:42
It doesn’t say anything about odd-numbered boxes,
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它并没有对奇数箱子 做出任何规定,
01:45
so we can just ignore the box marked with a seven.
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所以我们可以忽略 标着 7 的那个箱子。
01:48
What about the box with a red top?
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那么,那个红箱子呢?
01:51
Don’t we need to check that the number on the bottom is even?
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我们难道不需要检查 它的底部是偶数吗?
01:54
As it turns out, we don’t.
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事实证明,确实不需要。
01:56
The protocol says that if a box has an even number,
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规定说的是如果一个箱子标着偶数,
02:00
then it should have a red top.
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那么它的封顶应该为红色。
02:02
It doesn’t say that only boxes with even numbers can have red tops,
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它并没有规定 只有偶数箱子可以有红色封顶,
02:07
or that a box with a red top must have an even number.
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或者一个红色封顶的箱子 必须有偶数标记。
02:11
The requirement only goes in one direction.
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规定只要求了单方向的。
02:15
So we don’t need to check the box with the red lid.
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所以我们不需要检查 红色封顶的那个箱子。
02:17
We do, however, need to check the one with the black lid,
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不过我们确实需要检查 黑色封顶的箱子
02:21
to make sure it wasn’t incorrectly placed on an even-numbered box.
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来确保没有不小心把黑色封顶 放到了偶数箱子上。
02:26
If you initially assumed the rules imply a symmetrical match
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如果你一开始假定了 规定意味着
箱子上的数字和封顶颜色 是一个对称的对应关系,你不是一个人
02:30
between the number on the box and the type of lid, you’re not alone.
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02:33
That error is so common, we even have a name for it:
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这个错误常见到 我们甚至有一个名词来形容它:
02:37
affirming the consequent,
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肯定后件
02:39
or the fallacy of the converse.
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或逆命题谬误。
02:42
This fallacy wrongly assumes
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这种谬误错误的假设了
02:44
that just because a certain condition is necessary for a given result,
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只因为一个条件 是一个后果的必要条件
02:48
it must also be sufficient for it.
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那它一定是充分的。
02:51
For instance, having an atmosphere is a necessary condition
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举例来说,大气层
是一个可居住的星球的必要条件。
02:54
for being a habitable planet.
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02:56
But this doesn’t mean that it’s a sufficient condition –
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但这不意味着它是一个充分条件——
02:59
planets like Venus have atmospheres but lack other criteria for habitability.
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水星或其它星球也有大气层, 但是缺少其它居住的条件。
03:05
If that still seems hard to wrap your head around,
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如果这还是有点难理解,
03:08
let’s look at a slightly different problem.
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让我们看一个不太一样的问题。
03:11
Imagine the boxes contain groceries.
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想象一些装着杂货的袋子。
03:13
You see one marked for shipment to a steakhouse
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你看到一个标着运往牛排店
03:16
and one to a vegetarian restaurant.
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还有一个运往素食餐厅。
03:19
Then you see two more boxes turned upside down:
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然后你看到另外两个反着放的箱子:
03:22
one labeled as containing meat,
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一个标着含有肉,
03:24
and another as containing onions.
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另一个标着含有洋葱。
03:26
Which ones do you need to check?
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你需要检查哪个呢?
03:29
Well, it’s easy –
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这很容易——
03:30
make sure the meat isn’t being shipped to the vegetarian restaurant,
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确保肉不会被运到素食餐厅,
03:33
and that the box going there doesn’t contain meat.
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以及运到素食餐厅的箱子里没有肉。
03:37
The onions can go to either place,
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洋葱去哪里都可以,
03:39
and the box bound for the steakhouse can contain either product.
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而运往牛排店的箱子 可以含有任意一种食材。
03:43
Why does this scenario seem easier?
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为什么这个情况感觉更容易?
03:45
Formally, it’s the same problem –
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本质上,它是同一个问题——
03:47
two possible conditions for the top of the box,
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箱子上面有两种可能
03:50
and two for the bottom.
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底下也有两种。
03:51
But in this case, they’re based on familiar real-world needs,
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但这个问题是基于 我们现实生活中熟悉的需求
03:55
and we easily understand that while vegetarians only eat vegetables,
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所以我们很容易可以理解 虽然素食主义者只吃蔬菜,
03:59
they’re not the only ones who do so.
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但是他们不是唯一吃蔬菜的人。
04:02
In the original problem, the rules seemed more arbitrary,
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在原来的问题中, 规定看起来更随便一些,
04:05
and when they’re abstracted that way,
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而当它们被抽象成这样时,
04:08
the logical connections become harder to see.
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就更难看出隐含的逻辑关系。
04:11
In your case, you’ve managed to get enough supplies through
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在你的情况中,你成功的 让足量的物资运送过去
04:14
to enable the resistance to fight another day.
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以支撑反叛军继续战斗。
04:17
And you did it by thinking outside the box –
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而你能解决这个问题,就是因为 你的思考“跳出了箱子”——
04:20
both sides of it.
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它的两面。
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