What’s the difference between a scientific law and theory? - Matt Anticole

翻译人员: Yumeng Hao 校对人员: Ying Li

Chat with a friend about an established scientific theory

和朋友聊天，谈及已有的科学理论

and she might reply, "Well, that's just a theory."

她可能会说：“算了，那只不过是一个理论啦。”

But a conversation about an established scientific law

但是谈论已有的科学定律时，

rarely ends with, "Well, that's just a law."

很少有人会说：“算了， 那只不过是个定律啦。”

Why is that?

为什么会这样？

What is the difference between a theory and a law,

理论和定律有什么区别？

and is one better?

哪个更好？

Scientific laws and theories have different jobs to do.

科学定律和理论有不同的分工。

A scientific law predicts the results of certain initial conditions.

科学定律可以预测在特定初始 情况下可能出现的结果

It might predict your unborn child's possible hair colors,

它可以预测你未降生的孩子头发颜色

or how far a baseball travels when launched at a certain angle.

或者特定角度扔出的棒球会跑多远

In contrast, a theory tries to provide the most logical explanation

相反，理论只会从最符合逻辑的角度解释

about why things happen as they do.

为什么事情会这样？

A theory might invoke dominant and recessive genes

一个理论可能会引入显性和隐性基因

to explain how brown-haired parents ended up with a red-headed child,

来解释为什么棕色头发的父母 会生出红色头发的小孩

or use gravity to shed light on the parabolic trajectory of a baseball.

或者运用重力来阐释棒球的抛物线轨迹

In simplest terms,

简单来说

a law predicts what happens while a theory proposes why.

定律预测会发生什么 而理论解释为什么

A theory will never grow up into a law,

尽管定律和理论互相促进

though the development of one often triggers progress on the other.

一个理论永远不会演变成定律

In the 17th century, Johannes Kepler theorized cosmic musical harmonies

在17世纪，约翰尼斯·开普勒 将宇宙周期理论化

to explain the nature of planetary orbits.

来解释行星轨道的本质。

He developed three brilliant laws of planetary motion

他潜心研究几十年精确的天文数据

while he was studying decades of precise astronomical data

来找出天体运行的规律，

in an effort to find support for his theory.

并且提出了三个才华横溢的天体运行定律

While his three laws are still in use today,

虽然他的三个定律至今仍被使用，

gravity replaced his theory of harmonics to explain the planets' motions.

但是牛顿的万有引力定律已经取代了 他提出的周期定律来解释天体运动。

How did Kepler get part of it wrong?

开普勒怎么可能弄错了一部分呢？

Well, we weren't handed a universal instruction manual.

嗨，宇宙又没有给我们一本说明书。

Instead, we continually propose, challenge, revise, or even replace

事实上，我们一直在不断地提出新想法，

our scientific ideas as a work in progress.

不断的质疑、修改、甚至取代 现有的科学理论。

Laws usually resist change

定律一般来说不会被改变，

since they wouldn't have been adopted if they didn't fit the data,

因为他们不会因为与数据不符而被遗弃，

though we occasionally revise laws in the face of new unexpected information.

虽然我们有时会就新的不可预测的信息将其进行修改

A theory's acceptance, however, is often gladiatorial.

与其相反，接受一个理论常常需要一场争斗。

Multiple theories may compete to supply the best explanation

为了最好的诠释一个新的科学发现

of a new scientific discovery.

不同理论可能会相互竞争。

Upon further research,

在进一步研究前，

scientists tend to favor the theory that can explain most of the data,

科学家会更倾向于选择一个可以解释 最多现有发现的理论

though there may still be gaps in our understanding.

即使还有很多问题我们并不明白

Scientists also like when a new theory successfully predicts

科学家们还喜欢一个可以成功预测

previously unobserved phenomena,

以前没有观察到现象的新理论。

like when Dmitri Mendeleev's theory about the periodic table

就像门捷列夫的元素周期表

predicted several undiscovered elements.

预测了很多还未被发现的元素的性质。

The term scientific theory covers a broad swath.

科学理论这个概念其实覆盖面很广。

Some theories are new ideas with little experimental evidence

一些理论只是咸有实验数据支持的新想法

that scientists eye with suspicion,

科学家们眼带怀疑，

or even ridicule.

甚至嗤之以鼻。

Other theories,

其他理论

like those involving the Big Bang, evolution, and climate change,

比如大爆炸理论，进化论和气候变化等等

have endured years of experimental confirmation

都是经历了多年的实验证实

before earning acceptance by the majority of the scientific community.

才被科学大众所接受。

You would need to learn more about a specific explanation

在学习一个特定理论之前，

before you'd know how well scientists perceive it.

你要知道有科学家到底怎样看待它。

The word theory alone doesn't tell you.

因为理论这个词本身并不能告诉你什么。

In full disclosure,

总而言之

the scientific community has bet on the wrong horse before:

科学家们不是没有做出过错误的判断

alchemy,

炼金术

the geocentric model,

地心说

spontaneous generation,

无生源说

and the interstellar aether

还有星际以太

are just a few of many theories discarded in favor of better ones.

这些只是被正确理论抛弃的 众多理论中的一小部分。

But even incorrect theories have their value.

但是即使错误理论也有他们的价值。

Discredited alchemy was the birthplace of modern chemistry,

靠不住的炼金术是现代化学的发源地，

and medicine made great strides

而在我们理解细菌和病毒的作用之前，

long before we understood the roles of bacteria and viruses.

医学也取得了长足的进步。

That said, better theories often lead to exciting new discoveries

由此说来，更好的理论往往会带来

that were unimaginable under the old way of thinking.

前人无法想象的令人兴奋的新发现。

Nor should we assume all of our current scientific theories

但是我们也不应该假定所有的科学理论

will stand the test of time.

都会经得起时间的考验。

A single unexpected result is enough to challenge the status quo.

一个意想不到的结果就足够挑战了

However, vulnerability to some potentially better explanation

然而，科学理论不会因为存在

doesn't weaken a current scientific theory.

潜在的更好解释而衰弱

Instead, it shields science from becoming unchallenged dogma.

正好相反，不断创新让科学免于固步自封

A good scientific law is a finely-tuned machine,

一个好的科学定律像一个好机器

accomplishing its task brilliantly

能够出色的完成任务

but ignorant of why it works as well as it does.

但是我们对于它为何可以这样好的工作 知之甚少

A good scientific theory is a bruised, but unbowed, fighter

一个好的科学理论像一个伤痕累累 却依旧站立的斗士

who risks defeat if unable to overpower or adapt to the next challenger.

只有不能适应或者打败下一个 挑战者才会俯首认输

Though different,

即使定律和定律两者不同

science needs both laws and theories to understand the whole picture.

科学家仍然需要两者去掌控全局。

So next time someone comments that it's just a theory,

所以下次有人说那只是一个理论的时候

challenge them to go nine rounds with the champ

你可以让他们和冠军比九轮，

and see if they can do any better.

看看他们谁能赢。