and usually what I'm talking about

我在世界各地與大家討論達爾文

is Darwin's strange inversion of reasoning.

而最常提及的

Now that title, that phrase, comes from a critic, an early critic,

是他特殊的逆向推理

and this is a passage that I just love, and would like to read for you.

這個詞出自一位早期評論家

"In the theory with which we have to deal, Absolute Ignorance is the artificer;

我把最愛的一段評論分享給各位

so that we may enunciate as the fundamental principle of the whole system,

「據此理論，『無知』為萬物之始

that, in order to make a perfect and beautiful machine,

此一基本原則，為系統之基石

it is not requisite to know how to make it.

舉例而言，『要製造一台完美的機器

This proposition will be found on careful examination to express,

其實並不需要了解製造方法。』

in condensed form, the essential purport of the Theory,

達爾文經由縝密思慮得此論點

and to express in a few words all Mr. Darwin's meaning;

且以錘鍊之字句表明其主旨

who, by a strange inversion of reasoning,

簡單明瞭地傳達其意

seems to think Absolute Ignorance fully qualified

其逆向推理獨到之處

to take the place of Absolute Wisdom in the achievements of creative skill."

在於肯定『無知』，視其為難得之物

Exactly. Exactly. And it is a strange inversion.

可取代『全知』，輔創新之念於大成」

A creationist pamphlet has this wonderful page in it:

的確 這個理論確實背離一般常理

"Test Two:

神造世界論者的傳單上可能會問

Do you know of any building that didn't have a builder? Yes/No.

測驗二

Do you know of any painting that didn't have a painter? Yes/No.

有建築不出自建築者之手嗎？

Do you know of any car that didn't have a maker? Yes/No.

有畫作不出自創作者之手嗎？

If you answered 'Yes' for any of the above, give details."

有車子不出自製造者之手嗎？

A-ha! I mean, it really is a strange inversion of reasoning.

如果你都回答「有」，請舉例詳細說明

You would have thought it stands to reason

哈！這就是我所謂違常的逆向推理

that design requires an intelligent designer.

你可能一向認為

But Darwin shows that it's just false.

每個設計都需要厲害的設計師

Today, though, I'm going to talk about Darwin's other strange inversion,

達爾文卻認為這樣才不合理

which is equally puzzling at first, but in some ways just as important.

不過今天解釋的是其他逆向推理

It stands to reason that we love chocolate cake because it is sweet.

乍聽時一樣難懂，不過同等重要

Guys go for girls like this because they are sexy.

我們喜歡蛋糕，因為它是甜的

We adore babies because they're so cute.

男人都愛辣妹，因為她們性感

And, of course, we are amused by jokes because they are funny.

我們喜歡嬰兒，因為他們很可愛

This is all backwards. It is. And Darwin shows us why.

還有，笑話引人發噱是因為好笑

Let's start with sweet. Our sweet tooth is basically an evolved sugar detector,

達爾文解釋 這些推論都倒果為因

because sugar is high energy, and it's just been wired up to the preferer,

喜愛甜食是因為人對糖分很敏感

to put it very crudely, and that's why we like sugar.

我們需要糖的高能量 因此人腦

Honey is sweet because we like it, not "we like it because honey is sweet."

才將糖設定為我們喜歡的物質

There's nothing intrinsically sweet about honey.

蜂蜜會甜是因為我們喜歡蜂蜜

If you looked at glucose molecules till you were blind,

蜂蜜在本質上沒有甜的成分

you wouldn't see why they tasted sweet.

即使你死盯著葡萄糖的分子結構

You have to look in our brains to understand why they're sweet.

你還是不知道為什麼它是甜的

So if you think first there was sweetness,

原因其實就藏在我們的大腦裡

and then we evolved to like sweetness,

如果你先假定，甜食中有甜的成分

you've got it backwards; that's just wrong. It's the other way round.

我們的大腦演化成喜歡這種成分

Sweetness was born with the wiring which evolved.

那就錯了 應該要倒過來才對

And there's nothing intrinsically sexy about these young ladies.

甜味是隨著大腦的演化而誕生

And it's a good thing that there isn't, because if there were,

這些女生其實跟性感毫無關係

then Mother Nature would have a problem:

幸好沒有，因為如果有的話

How on earth do you get chimps to mate?

自然界會有大麻煩

Now you might think, ah, there's a solution: hallucinations.

黑猩猩怎麼願意跟伴侶交配呢？

That would be one way of doing it, but there's a quicker way.

你可能說 解決之道是：幻想

Just wire the chimps up to love that look,

這是一個方法；但還有一個更快的

and apparently they do.

就是改變黑猩猩的腦迴路

That's all there is to it.

讓牠們喜歡那種長相的伴侶

Over six million years, we and the chimps evolved our different ways.

奧秘說穿了就是這樣

We became bald-bodied, oddly enough;

演化至今，人跟黑猩猩已大不相同

for one reason or another, they didn't.

我們全身的毛髮退化

If we hadn't, then probably this would be the height of sexiness.

但出於某些原因 牠們的卻沒有

Our sweet tooth is an evolved and instinctual preference for high-energy food.

若我們也沒有，那或許這才是性感

It wasn't designed for chocolate cake.

我們喜歡甜食，是因為它的高能量

Chocolate cake is a supernormal stimulus.

跟巧克力蛋糕本身無關

The term is owed to Niko Tinbergen,

巧克力蛋糕是種超乎尋常的刺激

who did his famous experiments with gulls,

諾貝爾生物學獎得主丁柏格

where he found that that orange spot on the gull's beak --

做過一個有名的海鷗實驗

if he made a bigger, oranger spot

他發現海鷗嘴上那個橘色的點

the gull chicks would peck at it even harder.

如果變大一點或顏色更鮮豔一點

It was a hyperstimulus for them, and they loved it.

小海鷗啄食它時會更用力

What we see with, say, chocolate cake

它對小海鷗而言是個強烈的刺激

is it's a supernormal stimulus to tweak our design wiring.

實驗的意義是 超乎尋常的刺激

And there are lots of supernormal stimuli; chocolate cake is one.

像是巧克力蛋糕 會改變天性

There's lots of supernormal stimuli for sexiness.

還有很多東西是超乎尋常的刺激

And there's even supernormal stimuli for cuteness. Here's a pretty good example.

有些會引發性感的感覺

It's important that we love babies, and that we not be put off by, say, messy diapers.

有些會引發可愛的感覺 舉個例子

So babies have to attract our affection and our nurturing, and they do.

嬰兒必須討喜，所以即使弄髒尿布

And, by the way, a recent study shows that mothers

我們也不會因為這樣就不愛他們

prefer the smell of the dirty diapers of their own baby.

順道一提，最近一個研究指出

So nature works on many levels here.

媽媽喜歡聞自己寶寶的髒尿布

But now, if babies didn't look the way they do -- if babies looked like this,

看來大自然的影響無處不及呢

that's what we would find adorable, that's what we would find --

但是如果嬰兒現在是長成這樣

we would think, oh my goodness, do I ever want to hug that.

我們就會覺得這是可愛的

This is the strange inversion.

你可能會想「天啊！我才不要抱他」

Well now, finally what about funny. My answer is, it's the same story, the same story.

這就是逆向推裡

This is the hard one, the one that isn't obvious. That's why I leave it to the end.

最後 好笑的感覺 其實原理一樣

And I won't be able to say too much about it.

不過難解釋、也不明顯，所以放最後

But you have to think evolutionarily, you have to think, what hard job that has to be done --

而且我所知有限，能說的也不多

it's dirty work, somebody's got to do it --

但從進化的角度思考，什麼該先做

is so important to give us such a powerful, inbuilt reward for it when we succeed.

打樁的工作一定最難 但非做不可

Now, I think we've found the answer -- I and a few of my colleagues.

因為一旦成功 貢獻是超乎想像的

It's a neural system that's wired up to reward the brain

現在，我與幾個同事已經有了答案

for doing a grubby clerical job.

腦部的神經系統已經預設

Our bumper sticker for this view is

完成麻煩工作後應給予自己獎勵

that this is the joy of debugging.

我們對於這種反應的標準解釋是

Now I'm not going to have time to spell it all out,

這是解決麻煩的快樂

but I'll just say that only some kinds of debugging get the reward.

我在這裡只簡單說明一下

And what we're doing is we're using humor as a sort of neuroscientific probe

只有解決某些問題會覺得快樂

by switching humor on and off, by turning the knob on a joke --

我們把幽默感當成神經探測針

now it's not funny ... oh, now it's funnier ...

用來衡量一個笑話好不好笑

now we'll turn a little bit more ... now it's not funny --

現在不好笑....噢！現在好笑多了！

in this way, we can actually learn something

如果轉回來一點...現在又不好笑了

about the architecture of the brain,

透過這樣的解釋

the functional architecture of the brain.

比較容易理解大腦的構造

Matthew Hurley is the first author of this. We call it the Hurley Model.

就是能讓大腦發揮功用的構造

He's a computer scientist, Reginald Adams a psychologist, and there I am,

赫利貢獻最大，研究成果以他命名

and we're putting this together into a book.

另外還有心理學家亞當斯和我

Thank you very much.

我們正在整理研究成果準備出版