HoP 022 - 我知道，因为笼中的鸟儿在歌唱 - 柏拉图的《泰阿泰德篇》

嗨，我是彼得·亚当森，你正在收听的是《哲学史》播客，感谢伦敦国王学院和勒沃胡姆信托基金的支持，更多信息请访问 www.historyofphilosophy.net。

Hi, I'm Peter Adamson, and you're listening to the History of Philosophy podcast brought to you with the support of King's College London and the Leverhulme Trust online at www.historyofphilosophy.net.

今天的节目，我知道是因为笼中鸟在歌唱，讲的是柏拉图的《泰阿泰德篇》。

Today's episode, I know because the caged bird sings, Plato's Theaetetus.

那些经常和孩子相处的人都知道，在这个世界上，大人和孩子之间正进行着一场战争。

Those of you who spend time with children will know that between the adults and the children of this world, a war is raging.

这场战争的冲突每天早晨在全国各地上演，双方都动用了一切可用的武器。

Skirmishes in this war are fought across the land every morning, and both sides use all the weapons at their disposal.

发脾气、冷战、不给零食，甚至极端情况下，还有“淘气角”。

Tantrums, the silent treatment, withheld treats, even in extreme cases, the naughty steppe.

当然，我说的是穿多少衣服的问题。

I am speaking, of course, about the question of how warmly to dress.

孩子们在这个问题上的立场非常坚定。

The children's perspective on this issue is well entrenched.

外面根本没有你们父母说的那么冷，我们才不会穿那件厚外套，不过也许可以考虑穿件薄毛衣。

It is not nearly as cold outside as you parents would claim, and we aren't going to wear that winter coat, though we may be willing to consider a light sweater.

父母的观点同样坚定。

The parents point of view is equally firm.

你会冻出病来的。

You'll catch your death of cold.

我猜大多数收听这个播客的人都在12岁以上，所以自然更倾向于成年人的观点。

Now, I guess that most of the people listening to this podcast are above the age of 12, and so naturally favor the adult perspective.

我们很自然地认为，外面有多冷，这是一个客观事实。

There is, we quite naturally think, a fact of the matter about how cold it is outside.

看看温度计就知道了。

Just look at the thermometer.

但孩子们可以对我们说：可是我不觉得冷，所以对我来说，外面不冷。

Yet the children can turn to us and say, But I don't feel cold, so for me it isn't cold.

他们说得有道理，尽管这个道理在他们一边坚持说天气很暖和，一边开始发抖的时候，就有点站不住脚了。

And they've got a point, albeit a point which is undermined slightly when they start shivering, even as they're insisting on how warm it is.

关键在于，每个人对空气感觉有多冷，只有自己说了算。

The point is that it is for each person to say how cold the air feels to them.

你甚至可以说，不管温度是多少，空气的冷无非就是空气在我们每个人感觉中的冷。

You might even say that, whatever the temperature may be, the air's being cold is nothing more than the air's seeming cold to each of us.

这引发了一个令人不安的想法。

This prompts an unsettling thought.

空气本身既不冷也不热，这种说法并非没有道理，但对你来说是冷，对我来说是暖。

It's not implausible that the air is really neither cold nor hot in itself, but is cold for you and warm for me.

我在波士顿长大，所以我比你更耐寒。

I grew up in Boston, so I'm made of tougher stuff than you are.

我们还能想到其他例子。

And we can think of other cases.

我们大多数人都有过争论某件衣服是蓝色还是绿色的经历，也许对一个人来说它就是绿色，对另一个人来说就是蓝色。

Most of us have been in disputes about whether a certain piece of clothing is blue or green, and maybe it is just green for one person, blue for someone else.

于是，这个令人不安的想法就来了：如果所有事情都是这样呢？

Thus, the unsettling thought, What if everything is like this?

假设除了每个人感受到的样子之外，不存在其他真相。

Suppose that there is no truth apart from the way things seem to each person.

可能对我来说是温暖的，对你来说是寒冷的；对我来说是蓝色的，对你来说是绿色的；对我来说是好的，对你来说是坏的，但这些事物本身并不具备这些属性。

Things may be warm for me, cold for you, blue for me, green for you, good for me, bad for you, while having none of these features in themselves.

如果是这样的话，就没有绝对的真实，相反，真理是相对的：某件事对我可能是真的，对你可能是假的，但它本身既不是真的也不是假的。

In that case, nothing is true absolutely rather, truth is relative: something might be true for me and false for you, but neither false nor true in itself.

这种相对主义的真理观在当代哲学中依然存在，但它的根源可以追溯到柏拉图的对话录。

This relativist theory of truth is one that still arises in contemporary philosophy, but it has its roots in the dialogues of Plato.

特别是，它在我非常喜欢的柏拉图对话《泰阿泰德篇》中得到了探讨。

In particular, it is explored in my very favorite Platonic dialogue, the Theaetetus.

在之前的几期节目里，我提到过认识论这个词，它指的是对知识的探讨，因为古希腊语中表示知识或理解的词是episteme。

In a few previous episodes, I've mentioned the word epistemology, which means the study of knowledge, because the ancient Greek word for knowledge or understanding was episteme.

我们上周看到，柏拉图的《美诺篇》里有很多关于认识论的内容，而且我们发现前苏格拉底哲学家们就已经有了很有趣的认识论思想。

We saw last week that Plato's Mino has quite a bit to say about epistemology, and we found interesting epistemological ideas already in the Pre Socratics.

但第一部专门致力于认识论的著作是《泰阿泰德篇》。

But the first work to devote itself fully to epistemology is the Theaetetus.

它探讨了《美诺篇》中的一些观点，但走得更远，不仅研究了这种真理相对主义理论，还考察了错误判断是如何可能的，以及知识与信念之间的关系。

It explores some of the ideas of the mino but goes well beyond them, investigating not only this relativist theory of truth, but also the question of how false judgment is possible and how knowledge relates to belief.

主要人物有我们的老朋友苏格拉底、数学家塞奥多洛，还有一个年轻人，他像塞奥多洛一样是数学家，又像苏格拉底一样长得非常丑。

The main characters are our old friend Socrates, Theodorus, a mathematician, and a young man who is a mathematician like Theodorus and profoundly ugly like Socrates.

他和苏格拉底一样，眼睛突出，鼻子扁平。

He shares Socrates' protruding eyes and snub nose.

这就是泰阿泰德，他是柏拉图对话中与苏格拉底交流的最令人敬佩的角色之一。

This is Theaetetus, one of the most admirable characters ever to engage with Socrates in Plato's dialogues.

尽管他年纪轻轻，但他比年长的塞奥多洛更执着于哲学探索。

Despite his youth, he shows much more commitment to the philosophical search than the older Theodorus.

他多次尝试给知识下定义。

He offers several attempts at saying what knowledge might be.

正如我们在苏格拉底式对话中所预料的那样，每次尝试都被驳倒了，但他没有灰心，而且在对话过程中我们学到了很多关于知识的东西，尽管这些角色没能给出一个令他们满意的知识定义。

As we have come to expect in Socratic dialogues, each attempt is refuted, but he doesn't lose heart, and we learn a great deal about knowledge in the course of the dialogue, even if the characters fail to produce a definition of knowledge that satisfies them.

泰阿泰德的第一个尝试是说知识就是感知。

Theaetetus' first attempt is to say that knowledge is perception.

这里表示感知的词是aesthesis，顺便说一下，我们现在的“美学”这个词就来源于它。

The word for perception here is aesthesis, which incidentally is where we get the word aesthetics.

它可以指感官知觉，也就是视觉、听觉、嗅觉等等，或者更广泛地说，任何形式的感知，包括用心灵去感知事物。

It can mean sense perception that is, vision, hearing, smell, and so on or, more broadly, any kind of perception, including the perception of things with the mind.

特别是如果我们从更广义的角度来理解，塞埃泰图斯的定义看起来是合理的：当我们感知到某物时，我们就知道它。

Especially if we take it in this broader sense, Theaetetus' definition looks plausible: We know something when we perceive it.

或者，也许可以说，当我们理解到某件事确实如此时，我们就知道了。

Or, perhaps one might say, We know when we grasp that something is the case.

但苏格拉底指出，塞埃泰图斯的定义可能被理解成一种更令人不安的方式。

But Socrates shows that Theaetetus' definition could be taken in a more unsettling way.

如果知识就是感知，那么对我来说，凡是看起来如此的事情，对我来说就必须确实如此。

If knowledge is perception, then whatever seems to me to be the case must actually be the case for me.

这里，他举了一个我刚才用过的例子：风对我来说是温暖的，对你来说是寒冷的，所以我感知到风是温暖的，你感知到它是寒冷的。

Here, he gives the same example I used a moment ago: The wind seems warm to me and cold to you, so I perceive the wind as warm and you perceive it as cold.

如果感知就是知识，那就意味着我知道风是温暖的，而你知道它是寒冷的。

If perception is knowledge, then that means that I know the wind is warm and you know it is cold.

这怎么可能呢？

How could this be?

那得看真理是不是相对的了。

Well, only if truth is relative.

对我来说风是暖的，这对你来说是真的；对你来说风是冷的，这也是真的。但风本身并没有绝对的热或冷，它不依赖于任何观察者而存在。

It's true for me that the wind is warm and true for you that it is cold, but there is no such thing as the winds being truly warm or cold in itself relative to no perceiver.

毕竟，知识无非就是感知而已。

After all, knowledge is nothing but perception.

苏格拉底补充说，如果提出这样的观点，泰阿泰德并不孤单，因为有很多人都持类似看法。

Socrates adds that in putting forward such a view, Theaetetus would be in good company.

特别是，这种相对主义的真理论是由伟大的智者普罗泰戈拉提出的。

In particular, this relativistic theory of truth was asserted by the great Sophist Protagoras.

就像我们在上一期关于智者的节目中看到的那样，普罗泰戈拉以一句名言闻名：人是万物的尺度，是存在者存在的尺度，是不存在者不存在的尺度。

As we saw in our previous episode on the Sophists, Protagoras was famous for saying, Man is the measure of all things, of the things that are, that they are, of the things that are not, that they are not.

就像泰阿泰德将知识定义为感知一样，这句‘人是万物之尺度’的学说也可以有多种不同的解读方式。

Like Theaetetus' definition of knowledge as perception, this man is the measure doctrine could be taken in a lot of different ways.

但苏格拉底希望我们将这两种主张都归结为一种关于真理的相对主义。

But Socrates wants us to take both claims as boiling down to relativism about truth.

如果我是衡量风是否温暖的标准，那么风的温暖就只是对我而言的温暖，而不是对我而言的寒冷。

If I am the measure of whether the wind is warm, then there is nothing more to the wind's being warm, then it's being warm for me and not cold for me.

事物在我眼中的样子，决定了风对我来说是怎样的。

The way things seem to me determines the way the wind is and isn't for me.

但是，还有更多内容。

But wait, there's more.

苏格拉底补充说，塞埃泰图斯和普罗泰戈拉还有一位重量级人物支持他们，那就是前苏格拉底哲学家赫拉克利特。

Socrates adds that Theaetetus and Protagoras have another heavy hitter on their side, namely the Pre Socratic philosopher Heraclitus.

你可能还记得，我之前谈到赫拉克利特时说过，柏拉图把他这位杰出的前辈描绘成相信一种完全流变的学说。

You might remember that when I talked about Heraclitus, I said that Plato portrays his illustrious predecessor as believing in a doctrine of total flux.

也就是说，一切事物在各个方面都在不断变化，我们自身和周围的世界都没有稳定性。

That is, everything is constantly changing in every respect, and there is no stability in us or the world around us.

《泰阿泰德篇》并不是柏拉图将这种观点归于赫拉克利特的唯一对话，但它是最著名的例子。

The Theaetetus isn't the only dialogue where Plato ascribes this view to Heraclitus, though it is the most famous example.

但为什么流变学说会与真理相对主义相伴随呢？

But why does the flux doctrine go along with relativism about truth?

这个问题有点复杂，但基本的答案是，如果普罗泰戈拉的相对主义成立，那么我们周围世界的事物就不会有从一刻到下一刻的稳定本质。

This is a slightly complicated question, but the basic answer is that if Protagorean relativism is true, then the things in the world around us will have no stable natures from moment to moment.

它们只会是各种感知者所看到的样子，而根据这里所呈现的赫拉克利特的观点，这种样子一直在变化。

They will only be whatever they seem to be to various perceivers, and this is changing all the time, according to Heraclitus, as he's presented here.

所以，按照这种观点，结果就是没有什么是冷的，也没有什么是热的。

So, on this view, it would turn out that nothing is cold and nothing is warm.

相反，一切都在各个方面不断变化。

Rather, everything is always changing in every way.

实际上，情况可能比这更糟。

Actually, it might be even worse than this.

如果我们说从热变冷或从冷变热的东西既是热的又是冷的，那么空气就总是既热又冷。

If we say that what is changing from warm to cold or vice versa is both warm and cold, then the air will always be both warm and cold.

正是基于这一点，亚里士多德后来指责赫拉克利特否定了矛盾律。

It was with this in mind that Aristotle later accused Heraclitus of denying the principle of non contradiction.

流动学说的这些极端后果给了我们充分的理由去拒绝它，而如果接受相对主义真理观就意味着接受流动理论，那么也许我们也会放弃相对主义。

These radical consequences of the flux doctrine give us plenty of reason for rejecting it, and if buying into the relativist theory of truth means buying into the flux theory, then maybe we'll give up on relativism as well.

但普罗泰戈拉会试图说服我们，相对主义理论并没有看起来那么不合理。

But Protagoras will try to persuade us that the relativist theory isn't as implausible as it seems.

如果你对什么东西是好的感兴趣，那你显然关心的是哪些东西对你有益。

If you're interested in which things are good, then obviously what you're interested in is which things are good for you.

如果某样东西对别人好却对你不好，或者对任何人都没有特定意义，那它所谓的‘好’到底是什么意思呢？

What would it even mean for something to be good, but not for you, or for anyone in particular?

这也许把柏拉图所探讨的理论联系到了历史上真实的普罗泰戈拉身上。

This perhaps connects the theory Plato is considering to the real historical Protagoras.

他声称自己能够教授美德，并且可能认为这是可行的，因为善就是有益的东西，而他可以教你如何获得你认为有益的事物，比如政治权力。

He claimed to teach virtue, and may have supposed this was possible because the good is the advantageous, and that he could teach you how to get things you would consider to be advantageous, like political power.

普罗泰戈拉是否真的持有柏拉图在《泰阿泰德篇》中归因于他的那种激进的认识论理论，这当然是另一回事，但让我们先把它放在一边，也先把关于流变的难题搁置一旁，只考虑如何反驳那些采取真理相对主义立场的人这一问题。

Whether Protagoras really held the radical epistemological theory that Plato ascribes to him here in the Theaetetus is of course another matter, but let's leave that aside, and also leave aside the problems about flux and just consider the problem of how to refute someone who adopts the relativist position on truth.

现在，我知道你在想什么。

Now, know what you're thinking.

这很简单。

This will be easy.

只要指一下温度计，它告诉我们空气有多冷这个客观事实，但别急。

Just point to a thermometer, which tells us an objective fact about how cold the air is, but not so fast.

首先，普罗泰戈拉可以同意你的孩子们，不管温度计怎么说，对我们每个人来说，是冷是热都由我们自己说了算。

Firstly, Protagoras can agree with your kids that whatever the thermometer says, it's up to each of us to say whether it is cold or warm for us.

其次，他可以指出，温度计本身也是你感知到的东西。

Secondly, he can point out that the thermometer is itself something you perceive.

如果你觉得温度计显示的是，比如说，30度，那么对你来说，温度计显示30度就是真的。

If it seems to you that the thermometer reads, say, 30 degrees, then it's true for you that the thermometer reads 30 degrees.

对你来说是真的，仅仅因为你感知到它是这样。

It's true for you simply because you perceive it to be the case.

坚持认为温度计的读数有绝对真理，那只是假设存在一个独立于任何感知者的真理，而这正是普罗泰戈拉所否认的。

To insist on there being an absolute truth about the reading of the thermometer is just to assume that there is a truth independent of any perceiver, and that's what Protagoras denies.

人是万物的尺度，对吧？

Man is the measure of all things, right?

但苏格拉底还有几招别的招数。

But Socrates has a couple of other tricks up his sleeve.

他一开始就开骂了。

He starts with abuse.

那说猪或者狒狒是万物的尺度，不也一样成立吗？

Wouldn't it be just as true to say that a pig or a baboon is the measure of all things?

骂人当然解气，但这个论证没什么分量。

Abuse is always satisfying, of course, but this argument doesn't carry much weight.

好在，他还有更有哲学深度的观点要讲。

Fortunately, he has more philosophically satisfying points to make, too.

比如说，按照这个“人是万物的尺度”的理论，找专家咨询就没什么意义了。

For instance, on this man is the measure doctrine, there'd be no point consulting experts.

如果你自己跟医生一样能判断，那干嘛还花钱去看病呢？

Why pay to go to the doctor if you are just as good a measure as the doctor is?

如果你觉得吃阿司匹林能治好你那场严重的阑尾炎，那对你来说这就是真的。

If it seems to you that taking aspirin will cure that nasty bout of appendicitis, then it's true for you.

听起来这个理论会缩短信奉者的寿命，光凭这一点就足以否定它了。

This sounds like a theory that will reduce the life expectancy of its adherents, reason enough to reject it.

与此密切相关的一个反对意见是关于预测未来的。

Closely related is an objection about predicting the future.

如果我期望自己能从疾病中康复，那么对我来说，康复就是真的。

If I expect to recover from my illness, then it will be true for me that I will recover.

如果后来我又觉得自己仍然生病，那么我就会觉得自己没有康复，所以对我来说，没有康复就是真的。

If it then later seems to me that I'm still sick, then it will seem to me that I have not recovered, and so it will be true for me that I didn't recover.

很难看出这两者怎么能同时成立。

It's hard to see how both of these could be the case.

但苏格拉底最有趣的反对意见展示了一个经典且永远有用的哲学策略。

But Socrates' most interesting objection illustrates a classic, perennially useful philosophical maneuver.

每当你面对一个大胆的新理论，尤其是怀疑论的理论时，问问自己：这个理论本身能否成立？

Whenever you're presented with a bold new theory, especially a skeptical theory, ask whether the theory could be true on its own terms.

比如，如果有人说没有什么是真的，你可以问他，这个说法本身是不是真的。

For example, if someone says that nothing is true, you can ask him whether this claim is itself true.

或者，如果有人说语言没有意义，你可以问他，他是怎么用一句话把这个想法表达出来的。

Or if someone says that language is meaningless, you can ask him how he is able to convey this idea in a sentence.

同样地，苏格拉底指出，普罗泰戈拉的相对主义学说是不攻自破的。

In the same way, Socrates suggests that Protagoras' relativism doctrine is self refuting.

因为，即使普罗泰戈拉同意这个学说，苏格拉底也不同意。

For, even if Protagoras agrees with the doctrine, Socrates does not.

所以，对苏格拉底来说，普罗泰戈拉的学说就是假的。

Thus, it will be true for Socrates that Protagoras' doctrine is false.

而且，既然这是从普罗泰戈拉的学说中推导出来的，那么对普罗泰戈拉来说，这个学说对苏格拉底而言也是假的。

Indeed, since this follows from Protagoras' doctrine, it will even be true for Protagoras that for Socrates the doctrine is false.

因此，普罗泰戈拉不得不按照他自己的学说承认，他的学说是错误的。

Thus, Protagoras is bound by his own doctrine to admit that his doctrine is false.

但也许这个招数有点太巧妙了。

But maybe this trick is a bit too tricky.

即使普罗泰戈拉不得不承认这个学说对苏格拉底来说是假的，他也不必承认它本身是假的，或者真正意义上的假。

Even if Protagoras has to admit that the doctrine is false for Socrates, he doesn't have to admit that it's false in itself, or really false.

记住，按照他的观点，根本不存在什么真正是假或真正是真的东西。

Remember, according to him, there's no such thing as something's just really being false or true.

只有对你、对我、对苏格拉底来说，某件事才是假的或真的。

There's only something's being false or true to you, to me, to Socrates.

在我们变得更晕之前，先放下相对主义，来看看这个对话的另一个重要主题——错误信念的可能性。

Before we get any dizzier, let's leave relativism behind and move on to another major theme of this dialogue, the possibility of false belief.

这个主题是在泰阿泰德接受知识并非感知，并提出另一个建议时出现的。

This theme arises when Theaetetus accepts that knowledge is not, after all, perception, and makes another suggestion.

也许知识就是拥有一个正确的信念。

Perhaps knowledge is having a true belief.

毕竟，当我认识某件事时，我对它有一个信念，而且显然，这个信念不可能是错误的，所以为什么不可以说，当我对某件事有正确的信念时，我就认识它呢？

After all, when I know something, I have a belief about it, and obviously, it can't be a false belief, so why not say I know something when I have a true belief about it?

苏格拉底说，这听起来不错，但如果我们想坚持这个定义，就需要理解为什么有些信念是正确的，有些是错误的。

All well and good, says Socrates, but if we want to uphold this definition, we need to understand how it could be that some beliefs are true and others false.

在这里，我们又会遇到那些讨厌的智者派。

And here, we will run afoul of those pesky Sophists again.

有些智者派认为，说或相信任何错误的事情都是不可能的，这样一来，一切都只是说服的问题。

Some Sophists suggested that it is impossible to say or believe anything false, in which case everything is just a matter of persuasion.

这个挑战在柏拉图的几篇对话录里都出现过。

This challenge appears in several Platonic dialogues.

我们之前在《欧绪德谟篇》里已经看到过，但《泰阿泰德篇》可能又是最著名的例子。

We've already seen it arising in the Euthydemus, but the Theaetetus is again probably the most famous case.

这里支持智者派观点的论证，很像我们上次讨论的梅诺悖论。

The argument here for the sophistical view is rather reminiscent of Mino's paradox, which we looked at last time.

论证是这样的：要么我知道某件事，要么我不知道。

It goes like this: Either I know something, or I don't.

如果我知道，那我凭借知识就不会出错。

If I know about it, then I won't make a mistake about it, thanks to my knowledge.

但如果我不知道，那我根本没法思考它，所以也不会出错。

But if I don't know about it, then I can't think about it, so I won't be able to make a mistake then either.

换句话说，我对每件事要么有完全的知识，要么完全不知道，这两种情况下我都不会搞错。

In other words, I'll have either perfect knowledge of each thing, or no knowledge of it at all, and in neither case will I get things wrong.

所以，犯错或相信任何错误的事情都是不可能的。

So it's impossible to make a mistake, to believe anything false.

和米诺悖论一样，解决办法似乎是要说存在一个中间地带，我对某事物了解或掌握得足够多，以至于会犯错，但又没有好到不会出错的程度。

As with Mino's paradox, it looks like the way out is to say that there is some middle ground where I know or grasp something well enough to make a mistake about it, but not so well that I am immune to error.

苏格拉底提出了两个类比来说明这如何可能。

Socrates presents two analogies to suggest how this could work.

首先，他说，想象一下你的记忆就像一块蜡板，就是古希腊人用来写字的那种。

First, he says, imagine that your memory is like a wax tablet, the kind they used to write on in ancient Greece.

当你感知到某物时，就像在心灵的蜡上盖了一个印记。

When you perceive something, that's like a stamp making an impression in the wax of your mind.

有些人蜡质又硬又脏，学东西很慢。

Some people have tough, dirty wax and are slow on the uptake.

有些人蜡质很软，容易留下印记，但忘得也快。

Others have fluid wax and get impressions quickly, but lose them just as fast.

还有些人的蜡质非常理想，容易盖章，也能很好地保持印记。

Others have wax which is ideally suited, easily stamped, but also good at holding the impressions.

这其实是一个关于记忆如何运作的相当不错的比喻。

Quite a nice image of how memory works, really.

好的。

Okay.

那么现在来说说错误的判断。

So now for false judgment.

这种情况发生在你感知到的东西和你记忆中蜡板上已有的印记不匹配的时候。

That would happen when there is a mismatch between something you perceive and an existing impression in the wax of your memory.

比如，我以为自己在看一部巴斯特·基顿主演的无声电影，但实际上我搞错了。

For instance, I think I am watching a silent film starring Buster Keaton, but actually I'm confused.

屏幕上那个可爱的家伙其实是查理·卓别林，而我把视觉图像匹配到了蜡板上错误的印记上。

That lovable fellow on the screen is in fact Charlie Chaplin, and I'm matching the visual image to the wrong stamped impression in my wax tablet.

就像苏格拉底说的，这就像把右脚穿进了左脚的鞋里。

As Socrates says, It's like putting your right foot into your left shoe.

注意，这样就解决了那个诡辩式的困境。

Notice that this solves the sophistical dilemma.

我之所以会犯错，是因为在某种程度上我认识它，但在另一种程度上又不认识它。

I can make a mistake about something because in a way I know it, and in a way I don't.

我知道巴斯特·基顿是谁，因为我肯定认识他，才能在记忆里留下他的印象，但这并不保证我在认出巴斯特·基顿的时候不会出错。

I know who Buster Keaton is because I must have got acquainted with him to have an impression of him in my memory, but this doesn't guarantee that I'll be error free in identifying people as Buster Keaton.

这个类比很有说服力，而且这一次，对话中并没有直接否定这个提议。

This is a compelling analogy, and for once the proposal isn't exactly rejected in the dialogue.

相反，角色们意识到，即使这个类比适用于认错人和感知错误的情况，但还有很多错误判断的情况，它帮不上忙。

Rather, the characters realize that even if it works for cases of mistaken identity and perception, there are many cases of false judgment where it will not help.

比如，当我算七加五却得到十一的时候，到底发生了什么？

For instance, what is going on when I add seven and five and get 11?

这里根本没有感知在记忆里留下印象这回事，但我还是犯了错。

There's nothing here about impressions being made on our memory by perception, and yet I've still made a mistake.

所以苏格拉底又提出了另一个比喻，来代替蜡块。

So Socrates produces another image in place of the wax tablet.

他说，想象一下，你的灵魂就像一个鸟舍，一个鸟笼，里面有很多鸟在飞来飞去，每只鸟代表一条知识。

Imagine, he says, that your soul is like an aviary, a bird cage, with lots of birds flying around in it, each of which represents a piece of knowledge.

每当你学到东西，你就得到了一只鸟，把它放进你的鸟笼里。

Whenever you've learned something, you've acquired a bird and put it into your aviary.

当你把五加七算成十一的时候，其实就是你伸手进鸟舍里，抓出了十一号鸟，而不是十二号鸟。

What happens when you add five to seven and get 11 is that you reach into your aviary and pull out the 11 bird instead of the 12 bird.

同样，你对十一的知识反而让你犯了错，就像你对巴斯特·基顿的了解让你把他错认成查理·卓别林一样。

Again, your knowledge of 11 actually enables you to make the mistake, the way your knowledge of Buster Keaton enabled you to mistake Charlie Chaplin for him.

但苏格拉底和泰阿泰德认为这个模型也有问题。

But Socrates and Theaetetus decide that this model too is problematic.

这意味着，当你犯错时，恰恰是因为你有所知，才会搞错。

It means that when you make a mistake, it is precisely by virtue of knowing that you get things wrong.

矛盾的是，正是因为你了解十一，你才会对五加七产生错误的信念。

It is paradoxically because of your knowledge of 11 that you are able to have a false belief about five plus seven.

不过，不知疲倦的泰阿泰德又提出了另一个建议。

The indefatigable Theaetetus has another suggestion, though.

如果你的鸟舍里不仅有代表知识的鸟，还有代表无知的鸟呢？

What if your aviary contains birds representing ignorance as well as birds representing knowledge?

那么，当你犯错时，你只是抓错了鸟。

Then, when you make a mistake, you've just grabbed the wrong kind of bird.

但这把原本的目的给破坏了，原本是想解释我们怎么做到对某件事知道得刚好够犯错，但又不至于知道得太透彻而完全不会出错。

But that ruins the whole point, which was to explain how we can know something just enough to make a mistake about it without knowing it so well that we are immune to error.

所以，现在咱们走到哪一步了？

So, where does all that leave us?

又回到了起点，还是没有关于错误信念的一般性解释，但我们仍然觉得，也许知识和正确的信念是一回事。

Right back where we started, without a general account of false belief, but still thinking that maybe knowledge is the same thing as true belief.

啊，但并不是这样，苏格拉底说。

Ah, but it isn't, says Socrates.

咱们不妨想想陪审团的情况。

Just consider the case of a jury.

他们可能会被某个口才很好的律师说服，认为某个人无罪，而那个人确实是无辜的。

They might be persuaded by some fancy lawyer that a certain man is innocent of a crime, and the man really is innocent.

但我们不会说陪审团真正知道了真相，因为他们只是被律师那套 slick 的手段给说服了而已。

But we wouldn't say that the jury knows, since they only believed this because the lawyer was slick enough to persuade them.

所以，他们虽然有了正确的信念，但这还不算真正的知识。

Thus, they have a true belief, but not knowledge.

这个定义算是完了。

So much for that definition.

不过，泰阿泰德仍然觉得，而且今天认识论学者也倾向于同意，知识一定和真信念有关系。

Yet, Theaetetus still feels, and today's epistemologists tend to agree, that knowledge must have something to do with true belief.

也许知识就是真信念再加上点别的东西，那些陪审员缺的东西，但如果你比如是谋杀案的目击者，知道被告是无辜的，那你就有那个东西。

Maybe knowledge is true belief plus something else as well, something the jurors are lacking, but which you would have if you were, say, an eyewitness at the murder and know that the accused man is innocent.

要说清楚那是什么，可不是件容易的事。

It's no easy task to say what that would be.

就像我说的，现代认识论学者还在纠结知识和真信念的关系问题。

As I say, modern day epistemologists are still struggling with the question of how knowledge relates to true belief.

他们这么做，其实是在回应《泰阿泰德篇》里首次提出的挑战。

In so doing, they are taking up a challenge first thrown down here in the Theaetetus.

在对话的其余部分，苏格拉底和泰阿泰德探讨了这样一种可能性：你需要给真信念加上某种理性解释，也就是逻各斯，赫拉克利特最喜欢的那个词，才能把它变成知识。

For the rest of the dialogue, Socrates and Theaetetus explore the possibility that some kind of rational account, a logos, that favorite word of Heraclitus, is what you'd need to add to true belief to render it into knowledge.

不出所料，他们没能成功，但我们确实对知识有了更多了解，特别是当你相信某件事时，知识如何与给出解释相关，又如何不相关。

As we expect by now, they don't manage to make this work, and yet we do learn a bit more about knowledge, in particular, how it does and does not relate to giving an account of yourself when you believe something.

对话的最后这部分相当复杂，要把它讲清楚可不容易，而且我时间也快不够了，所以今天就先讲到这里。

This last part of the dialogue is sufficiently complicated that giving an account of it would be no easy matter, and I'm just about out of time anyway, so I'll close there for now.

但柏拉图关于信念和知识的态度，在接下来的几集中仍将是重点。

But Plato's attitude towards belief and knowledge will continue to take center stage in the next few episodes.

两周后，我终于要讲柏拉图的理念论了，并探讨提出理念是否能帮助我们理解知识的本质。

In two weeks, I'll finally be looking at Plato's theory of forms, and trying to discover whether postulating forms could help us understand what knowledge is.

不过下次，我的同事M会再次出现。

But next time, we'll have a return appearance by my colleague M.

M.

M.

麦凯布，她会和我聊聊柏拉图关于知识的观点。

McCabe, who will chat with me about Plato's views on knowledge.

所以千万别错过下周的《无缝隙哲学史》节目。

So don't make the mistake of missing next week's episode on the history of philosophy without any gaps.