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Aristotle once described humans as “the rational animal.”

亞里斯多德曾將人類形容為「理性的動物」

Well, actually, he said that “man is the rational animal,” but we don’t have to

痾...事實上他是說「男人是理性的動物」但他有性別歧視不代表

be sexist just because he was.

我們必須效仿他

And if you’ve ever gotten into an argument with someone about religion or politics or which

如果你曾經和人因為宗教、政治或者漢斯沃兄弟中

Hemsworth is the hottest, then you’ve experienced how irrational people can be about their opinions.

哪一個最帥，你就會知道人們對於他們想法的堅持有多不理性

But what Aristotle meant is that rationality is our distinguishing characteristic – it’s

但亞里斯多德這句話的意思是理性是我們專有的特質

what sets us apart from the beasts.

是一個使我們與其他野獸產生區隔的特質

And no matter how much you disagree with someone about God or Obama or Chris Hemsworth, you

無論你有多不認同他人對於上帝、歐巴馬和克里斯·漢斯沃的想法

can at least grant that they are not beasts.

至少你會承認他們不是野獸

Because, most of the time at least, people can be persuaded. By arguments.

因為，大部份的時候，人是可以被說服的：藉由論證

You use arguments all the time -- in the comments, at family dinners, with your friends -- you

你無時無刻都在利用論證：在影片下的評論、在和家人餐桌上、和朋友相處時

probably just don’t think of them the same way that philosophers do.

你很可能只是對論證的想法和哲學家們不同

When you try and convince your parents to loan you the car, or when you’re talking

當你試圖說服你的父母借車給你、或當你和你的朋友談論速成班時

up Crash Course to your friends, you are using arguments. Thanks, by the way.

你就在使用論證，順道一提，感謝推薦！

Each time you tell someone to do or believe something -- or when you’re explaining why

每當你要求他人相信或去做某件事，或當你在解釋妳為什摩

you do or believe something -- you are giving an argument.

做某件事或相信某件事時，你就是再提出論證

The problem is, the vast majority of people aren’t really good at arguments.

問題是，大部份的人並不擅長於論證

We tend to confuse making a good argument with, like, having witty comebacks, or just

我們常常將提出好的論點和機智的應答還有

making your points more loudly and angrily, instead of building a case on a solid foundation

說話比較憤怒大聲混為一談，而非把自己的論點建立在有

of logic. Which can be harder than it sounds.

穩固根基的邏輯上。這做起來可比聽起來難！

But learning about arguments and strong reasoning will not only make you a better philosopher,

但學會論證和有利的推論不但能讓你成為更好的哲學家

it will also set you up to be a more persuasive person. Someone who people will listen to.

也能讓你成為更有說服力的人、讓人更願意傾聽的人

Someone who’s convincing.

一個可信的人

So, yeah, these skills are beneficial no matter what you want to do with your life.

所以無論你將來想做什麼，這個技巧都對你有幫助

So you might as well know how to argue properly.

你也可能因此知道怎麼正確的辯論

[Theme Music]

If you want to learn how to argue, then you should probably start about 2400 years ago,

如果你想知道怎麼辯論，可能要從2400年前說起

when Plato was laying out how reason can, and should, function in the human mind.

當時柏拉圖提出了理性如何，而且必須運行於人類的心智之中

He believed that we all have what he called a tripartite soul – what you might think

他相信一個我們稱之為「靈魂三分說」的理論，你可以想成是

of as your “self,” or your psyche, divided into three parts.

你的自我或你的心智被分成三個部分

First, there’s the rational, or logical part of the soul, which represents cool reason.

第一部分是理性，靈魂中邏輯的部分代表著冷靜的理性

This is the aspect of your self that seeks the truth and is swayed by facts and arguments.

這一部分的自我追尋著真理並由事實與論證支配

When you decide to stop eating bacon for two meals a day because, as delicious as it is,

當你決定停止吃培根，因為即使它很好吃，它對你的身體不好

it’s bad for you, then you make that decision with the guidance of the rational part of your soul.

這時就是你靈魂的理性部分引導你做出的決定

But then there’s the spirited aspect, often described as the emotional part of the self,

另外靈魂中也有精神部分，被認為是自我的情感部分

although that doesn’t really quite capture it.

不過說是情感並不完全精準

The spirited soul isn’t just about feeling -- it’s also about how your feelings fuel your actions.

精神靈魂並不只是感覺上的，他同時也解釋你的感覺如何導致你的行動

It’s the part that responds in righteous anger at injustice, the part that drives your

這一部分的靈魂使你對不公不義的事情義憤填膺，讓你充滿雄心壯志

ambition, and calls upon you to protect others.

讓你想要保護其他人

It gives you a sense of honor and duty, and is swayed by sympathy.

精神靈魂給予你榮譽感和責任感，由同情心支配

So if you decide to stop eating bacon because you just finished reading Charlotte’s Web,

所以當你決定不吃培根因為你剛看完了《夏綠蒂的網》

and now you’re in love with Wilbur, then you’re being guided by the spirited part of your soul.

愛上了裡面的小豬Wilbur，你就是受到了精神部的靈魂的引導做出的決定

But we share the next part of our soul with other animals, be they pig, or moose, or aardvark.

但第三個部分的靈魂是我們和其他動物共有的，例如豬、麋鹿和土豚

The appetitive part is what drives you to eat, have sex, and protect yourself from danger.

靈魂的情慾部分驅使我們去吃、去做愛、和保護自己遠離危險

It is swayed by temptations that are carnal, and visceral.

他由肉體和內在的誘惑支配

So at those times when you go ahead and just EAT ALL THE BACON because it just smells so

當你勇往直前吃了所有的培根只是因為他們聞起來太香了

dang good, the appetitive aspect of your soul is in control.

就是你的情慾靈魂正在控制你

Now, Plato believed that the best human beings -- and I should point out here that Plato

柏拉圖相信最好的人（這裏我們要指出的是柏拉圖

most definitely did believe that some people were better than others -- are always ruled

肯定相信某些人比起其他人是「更好的人類」）永遠是被靈魂的

by the rational part of their soul, because it works to keep the spirited and the appetitive parts in check.

理性部分所控制，因為理性靈魂能確保精神靈魂和情慾靈魂不要失控

People who allow themselves to be ruled by their spirited or appetitive selves are base,

他相信那些讓自己被情慾或精神的自我控制的人則是比較低下

he believed, and not fully, properly human.

不完全，不正派的人類

Now, most of us don’t buy into the concept of the tripartite soul anymore -- or the idea

現在大部份的人已經不太相信這個靈魂三分說或是

that some humans are less human than others.

相信有些人比起其他人是比較「不完全」的人類

But we do understand that we’re all motivated by physical desires, emotional impulses, and rational arguments.

但我們都理解我們會被物質慾望、情感衝動和理性的論證激勵

And philosophers continue to agree with Plato that reason should be in the driver’s seat.

許多哲學家也還是同意柏拉圖認為理性應該要處於主導地位的論點

So, how do you know if you’re good at it? How can you test your reasoning?

所以你要怎麼知道你是否很會運用理性？如何檢驗你的論證？

Well, let’s head over to the Thought Bubble for some Flash Philosophy.

我們進入思想泡泡來點哲學快閃

Throughout this course, we’re going to apply our philosophical skills by pondering puzzles, paradoxes, and thought experiments.

在這堂課中，我們將運用我們藉由思考謎題、悖論和思想實驗來運用我們的哲學技巧

Because remember: Philosophers love thinking about questions -- especially ones that don’t have ready answers.

因為記住，哲學家喜歡思考問題，尤其是那些沒有現成答案的問題

So think of these exercises as philosophical wind-sprints -- quick tests of your mental abilities.

你可以把它想成是一種哲學短跑競賽，一個能快速檢測你心智能力的小測驗

And here’s a doozy, from 20th century British thinker Bertrand Russell, one of the pioneers

這裏有一個二十世紀英國思想家伯特蘭·羅素想出來的難題，他是

of what’s known as analytic philosophy.

所謂分析哲學的先驅

Say there’s a town in which all men are required by law to be clean-shaven. This town

有一座城裡，所有的人都被法律要求必須把鬍子剃光

has only one barber, a man, who must follow strict rules:

這座城只有一個理髮師，他必須遵守以下規定：

Rule number one: He must shave all men who do not shave themselves.

規定一、他必須幫所有「沒有幫自己剃鬍子的人」剃鬍子

Rule number two: He must not shave any man who does shave himself.

規定二、他不能幫「幫自己剃鬍子的人」剃鬍子

It’s the nightmare of every libertarian and every mustachio’d hipster. But here’s the question:

這絕對是每個自由主義者和蓄鬍嬉皮的惡夢，但這裡的問題是：

Does the barber shave himself?

這位理髮師是否幫自己剃鬍子？

Cause think about it: The barber only shaves men who don’t shave themselves. So if he does

想想看：理髮師只幫「不幫自己剃鬍的人」剃鬍，所以

shave himself, then he must not, because the barber’s not allowed to shave guys who shave themselves.

如果他幫自己剃鬍，這是不可能的，因為他不被允許幫「幫自己剃鬍的人」剃鬍

But, if he doesn’t shave himself, then he has to be shaved by the barber, because that’s the law.

但如果他不替自己剃鬍，他就必須讓理髮師剃鬍，因為這是規定

Russell came up with this puzzle to illustrate the fact that a group must always be a member of itself.

羅素想出這個謎題以闡述一個事實：一個集合（group）必定包含一個成員（member）也就是自己

That means, in this case, that “all men who shave themselves” has to include every

這代表，在這個情況中「所有幫自己刮鬍子的人」必須包含

guy who shaves himself, including the barber.

每一個「幫自己刮鬍子的人」，包括這個理髮師

Otherwise, the logic that dictates the group’s existence just doesn’t hold up.

否則，邏輯上聲稱這個集合存在的論證就不能成立

And if the barber is a logical impossibility, then he can’t exist, which means the reasoning

如果這個理髮師在邏輯上是不可能的，他就不可能存在，也就是說

behind his existence is inherently flawed.

他存在的推論有本質上的缺陷

And philosophy doesn’t tolerate flawed reasoning.

而哲學家不會容忍有缺陷的推論

So, how do we make sure that we’re ruled by good, sound, not-flawed reason?

所以我們該怎麼知道我們是被好的、健全的、無缺陷的推論所支配呢？

By perfecting the art of the argument.

藉由努力雕琢自己辯論的藝術

An argument, in philosophy, isn’t just a shouting match.

辯論，哲學上來說，並不是比誰說話大聲而已

Instead, philosophers maintain that your beliefs should always be backed up by reasons,

相反的，哲學家認為你相信的事物永遠必須藉由論據支持

which we call premises.

我們稱之為前提

Premises form the structure of your argument. They offer evidence for your belief, and you

前提建構出你論證的架構，它們提供了你所信之事的證據，只要你想

can have as many premises as you like, as long as they support your conclusion, which

你可以提出無限多的前提，只要它能支持你的結論即可，而該結論

is the thing that you actually believe.

就是你所相信之事

So, let’s dissect the anatomy of an argument.

我們來解析一下一個論證

There are actually several different species of arguments. Probably the most familiar,

有很多種不同種類的論證，或許最廣為人知的

and the easiest to carry out, is the deductive argument.

也是最容易進行的，就是演繹論證

The main rule of a deductive arguments is: if your premises are true, then your conclusion must be true.

演繹論證的主要原則就是：如果前提為真，你的結論必為真

And knowing that something is actually true is very rare, and awesome.

而知道某是真的為真事實上是相當少見的情況，但有的話就非常棒！

So, here’s a boiled-down version of a good deductive argument:

這裡有一個精簡版本的優秀演繹論證：

Premise 1: All humans are mortal.

前提一：所有人都難逃一死

Premise 2: Socrates is a human.

前提二：蘇格拉底是人

Conclusion: Socrates is mortal.

結論：蘇格拉底終究會死

This kind of reasoning, where one fact leads to another, is called entailment.

這種論證，藉由一個事實帶到另一個事實，稱為蘊含（entailment）

Once we know that all humans are mortal, and that Socrates is a human, those facts entail that Socrates is mortal.

當我們知道人類是會死的，而蘇格拉底是個人類，這些事實蘊含了蘇格拉底會死的事實

Deduction begins with the general – in this case, what we know about human mortality – and

演繹法常從從普遍的事物開始，在這個例子中，我們都知道人類不免一死

reasons down to the specific – Socrates in particular.

並推論出普遍中的一個特定部分，也就是蘇格拉底，會死

What’s great about deductive arguments is that the truth of the premises must lead to

演繹論證很棒的地方是前提為真必會導致

the truth of the conclusion.

結論為真

When this happens, we say that the argument is valid – there’s just no way for the

當這種情況發生時，我們就能說這個論證是有效的（valid ），這時如果前提為真

conclusion to be false if the premises are true.

結論不可能不為真

Now check out this argument:

現在檢視一下下面這個論證：

All humans are mortal. Socrates is a human. Therefore, Socrates was Plato’s teacher

所有人類都不免一死，蘇格拉底是人類，所以蘇格拉底是柏拉圖之師

That argument is invalid, because nothing about human mortality can prove that Socrates was Plato’s teacher.

這個論證是無效的（invalid），因為人類不免一死的事實並無法證明蘇格拉底是柏拉圖的老師

As you might have noticed, there are plenty of mortal humans who never taught Plato.

就如你可能發現的事實，有很多非永生的人類並沒有教過柏拉圖

What’s interesting, though, is that this argument does happen to have a true conclusion,

有趣的是，即使如此，這個論證的結論卻恰巧為真

which leads us to another issue. And that is:

這引導我們到另一個課題：

Validity is not the same as truth.

有效性不代表真實性

All ‘valid’ really means is that if the premises are true, then your conclusion can’t be false.

有效意義是指如果前提為真，你的結論不可能為假

But that doesn’t mean that your premises prove your conclusion to be correct.

但不代表你的前提能證明你的結論是正確的

Like, in the case of whether Socrates was Plato’s teacher, the premises are true,

例如在這個蘇格拉底是否為柏拉圖之師的例子中，前提為真

and the conclusion is true, but the argument is still not valid -- because the premises

結論也為真，但論證還是無效的，因為它的前提

don’t in any way prove the conclusion. It just happens to be true.

無法以任何方式證明他的結論，只是結論剛好正確而已

So, if your premises don’t guarantee the truth of your conclusion, then you can end up with some really crappy arguments.

所以如果你的前提並沒有保證你的結論為真，你可能會做出一些很彆腳的論證

Like this one: - All cats are mammals

例如：所有的貓都是哺乳類

- I’m a mammal - Therefore, I’m a cat

我是個哺乳類，所以我是隻貓

As much as part of me would like to be my cat, this is invalid because the conclusion

雖然我有一點想當我的貓，但這個論證是無效的，因為它的前提

doesn’t entail from the premises…at all.

並完全不蘊含他的結論

I mean, all cats are mammals, but all mammals aren’t cats. Which means there are such

我的意思是，所有的貓都是哺乳類，但並非所有哺乳類都是貓，也就是說

things as non-cat mammals, which I am just one example of.

有一些叫做非貓哺乳類的東西存在，我就是一個例子

And it probably goes without saying, but you can have a perfectly valid argument and still have a false

可能更不用說的是，你可以有一個完美有效的論證，但結論還是不為真

conclusion, if any of your premises are false. For example: - All humans have tails

如果任何一個前提是錯的的話。例如：所有人類都有尾巴

- My brother John is a human - Therefore, John Green has a tail!

我兄弟John是個人類，所以John有尾巴

The argument is totally valid! – Because the premises entail the conclusion! The reasoning totally stands up!

這個論證完全是有效的，因為前提蘊含了結論！這個推論完全站得住腳！

It’s just that one of the premises is flawed.

只不過其中一個前提是錯的

Since I’m reasonably certain that John doesn’t have a tail -- I’ve seen him in a bathing

因為我相當肯定John並沒有尾巴，我看過他穿泳衣

suit -- this argument is not deductively sound.

這不是個演繹上確固（sound）的論證

And a deductively sound argument is one that’s free of formal flaws or defects.

演繹上確固的論證是沒有任何缺陷或瑕疵的

It’s an argument whose premises are all true, and that’s valid, which means its

當有一個論證前提都為真，並且有效，意味著

conclusion is guaranteed to be true.

結論一定為真

So, sound arguments should always be your goal.

所以，確固的論證就是你的目標

The reason that deduction is prized by philosophers -- and lots of other important kinds of thinkers

演繹法被哲學家和很多重要的思想家視為珍寶的原因

-- is that it’s the only kind of argument that can give you a real certainty.

是因為這是唯一一種能給你確切答案的論證法

But it’s limited, because it only works if you’re starting with known, true premises, which are hard to come by.

但他還是有限制，因為它只能從你已知且為真的前提開始，而已知且為真的前提是很稀少的

And for what it’s worth, deductive truths are usually pretty obvious. They don’t tend

而它有什麼價值？演繹出的事實通常非常明顯，它們

to lead us to startlingly new information, like the fact that I’m not a cat, or that John doesn’t have a tail.

不會帶給我們驚人的訊息，像是我不是隻貓和John並沒有尾巴的事實

So instead of starting with premises that are already certain, like deduction does,

所以除了從我們已確知的前提開始，例如演繹法之外

you’re gonna have to know how to determine the truth of, and your confidence in, your premises.

你必須知道如何分辨你的前提是否為真、並且獲取對你的前提的自信

Which means you’re going to have to acquaint yourself with the other species of arguments,

這表示你必須理解其他類型的論證

which we’re gonna do next time.

我們下次會談到它們

But today, we talked about the value of reason, the structure of arguments, and we took a

但今天，我們講到了理性的的價值、論證的結構、並深究了

close look at one kind of argument: deductive reasoning.

其中一種論證法：演繹論證

This episode of Crash Course Philosophy is made possible by Squarespace. Squarespace

這集哲學速成班由Squarespace贊助播出

is a way to create a website, blog or online store for you and your ideas. Squarespace

Squarespace是一個能為你和你的點子創造出網站、部落格和網路商店的好途徑

features a user-friendly interface, custom templates and 24/7 customer support. Try Squarespace

有使用者友善介面、自訂樣板和全天候的客戶支持，請在

at squarespace.com/crashcourse for a special offer.

at squarespace.com/crashcourse試用Squarespace獲取而外好康

Crash Course Philosophy is produced in association with PBS Digital Studios. You can head over

哲學速成班與公共電視網數位工作室合作撥出，你可以去他們的頻道