科学，我们如何知道我们所知道的？

文/ 博江盟（Jean-Marc Bovet，瑞士） 译/孙梦格

我是一名医药科学家，但我不打算谈论我的专业领域，而是希望聊聊这些年来我作为一个热爱科学的人的一些思考——具体来说，即我们如何知道自己究竟知道些什么？

什么是知识？

让我们先从科学的定义谈起吧。科学知识是关于某一特定主题、经过“系统性组织”的“信息体系”。首先，我们需要有信息输入，换句话说，我们的大脑先要收集通过感官感知到的原始数据；其次，我们还要把这些数据组织成一个“故事”，而这个故事我称其为科学知识。信息的输入主要依赖于感官，如触觉或听觉。当你用手捧住雪的时候，你就会收集到关于雪的信息。然后，你的大脑把这些感觉组织起来：它是冷的，它融化了，它变成了水。这就形成了“故事”。这个“故事”不仅来源于你的感知，还可能受到你对雪的预设所带来的影响。通过观察收集更多的信息并把它们组织在一起，我们就能够讲出更丰富的故事。这些故事聚合在一起就成为科学理论。科学理论必须始终与物质世界保持一致。通过对物质世界进行观察，并经实验确认所得的想法，就形成了知识。

In this article,I’m not going to talk about my profession as a pharmaceutical scientist.Instead,I’m going to talk about some reflections I have had over the years as a person who loves science,to be specific,how do we know what we know.

What is knowledge?

Let’s begin with the definition of science.We can define scientific knowledge as a “systematically organized body of information” on a particular subject.Firstly,there is the body of information,or in other words,our brain gathering raw data we perceive through our senses.Secondly,there is the way to organize the data to create a “story” that I would call scientific knowledge.The primary information comes from senses,such as touching or hearing.For example,you will gather the information about snow when you have the chance of holding it in your hands.Then your brain organizes the sensation you have had: it is cold,it melts and it changes into water into the “story”.That “story” is not only based on your perceptions but may also influenced by your preconceptions of what snow is like.The more information you gather through observation,the bigger the stories will be after you organize them,which forms scientific theories.The scientific theories must always be consistent with the physical world so that knowledge is what we believe filtered by observation and experimentation of the physical world.

大脑的认知和人类的感官

我们的大脑可以看作是由两个回路构成的，其中一个回路反应很快，主要依靠记忆的储备；而另一个则比较慢，靠的是思维和处理信息的能力。这两个回路共同作用，一起对接收到的信息作出判断。

人类只能接收到有限的信息，因为我们所知道的一切都来自以下五感：嗅觉、触觉、味觉、听觉和视觉。它们是人类收集到的所有信息的最初来源。

我们可以试着触摸一下自己身体的不同部位，你会发现手掌内侧要比臂膀敏感得多，哪怕是很细小的东西也能感觉得到。

那么，听觉呢？人在发出声音时，其实是在空气中产生了一个声波，听者的耳朵捕捉到这个波，也就听到了声音。但是人的耳朵并不能听到所有声音，我们只能听到一小部分声音，音调太低或者太高都不行，即人类的听觉有一个频率范围。而狗能收听到的频率范围更大，能感知到更高的音调，所以你可以买到只有狗才能听到的哨子来驯犬而不用担心打扰邻居。

很多动物对声音的接收范围都不一样。蝙蝠就非常特别，它们可以发出并收听到一种叫作超声波的高频声音。蝙蝠正是利用这种声音来“看”世界的——它们可以利用超声波回声定位周围环境，并且锁定猎物的位置。

那么，我们是如何看见东西的呢？这和周围的光有关。光也像波一样运动，有着振幅和波长的属性。但与声音不同的是，光是一种电磁波。

和听觉差不多，我们的视力也有局限，只能看到所谓的“可见光”，它只占到了电磁波谱的一部分。一个普通人的眼睛能感知到400—700nm波长段的光线。

蜜蜂与人类不同，仅仅能看到波长极短的光线。蜜蜂的可见光波长在300—600nm。所以，对两个不同的物种来说，同一朵花可能看上去完全不同。

Our brian and senses

We can see our brain as having two circuits that differentiate what is true from what is false.One circuit is very fast and relies on memory,while the other one is slower and relies on your thinking and your processing of information.

As human beings,we are limited because everything we know comes from the following five aspects: the smell,the touch,the taste,the hearing and the sight.All the information we gather,originally comes from these five senses.

We can try to touch different parts of your body and you can find out that,for example,the inside of your hands is much more sensitive than your arm.You can feel even the very small things.And you cannot feel the same things on your arm.

So how about our hearing ability? What is hearing? When making noise,one is actually producing a wave in the air that goes toward one’s ear.Then others can perceive that sound as catching that wave.Human ears can’t hear all sounds.We can actually hear a small fraction of sound in the human pitch range and can’t hear the sound either too high or too low.There is 9 window of pitches of sound where one can actually hear.While human ears have their preferred frequencies,dogs have a larger range.Dogs can perceive sounds of much higher pitch than humans do.You can buy whistles that only dogs can hear and use it to train them without disturbing the neighbors.

Many animals have different frequencies in terms of sound reception.For example,bats can produce and hear a kind of high frequency sound called ultrasound.Bats use this sound to “see” the world.They can echolocate their environment and find where their prey is.

Now I’m going to talk about what we see.Take light as an example.Light also acts like a wave featuring amplitude and wavelength.However,it is different from sound because it is electromagnetic.

And the same is true as before,we have limitations on our sight,that is,we only see what is called “visible light”,which only consists of a portion of the electromagnetic spectrum.A typical human eye will respond to wavelengths from about 400 to 700 nanometers.

Bees,unlike human beings,can see very short wavelengths.For example,a bee’s visible wavelength ranges from 300 to 600 nanometers,compared to human’s 400 to 700 nanometers.That is why the same flower may appear very different to two different species.We don’t see the same thing.

由于感官的局限性，我们需要利用仪器设备来将自己无法感知到的信息转化为可以看到或听到的东西。仪器的使用是对人类感官的扩展。不过我想告诉你们的是，这个宇宙中每时每刻都发生着很多事情，就算是用上所有的感官，我们仍然不能感知到全部这些事物的存在。

思考与大脑对信息的解读

思考能力是我们大脑的另一个重要作用。我们用大脑来理解收集到的所有信息。一种理解的方式是演绎：从理论到假设，再到观察，通过观察最后确认假设。历史上，亚里士多德等哲学家提出过这种思维方式。另一种思维方式则更像福尔摩斯：我们首先像一个侦探一样观察，然后从中发现一个模式，形成一个假设，最后浓缩出一个理论。

“洞穴之喻”是柏拉图著名理论之一。故事中苏格拉底描述了这样一个人：他的一生都被锁链锁住，只能面对着山洞里的一面空白墙壁。这个人的身后有一团燃烧着的火焰。他日日夜夜看到的都是从他身后的火堆前经过的物体投射在墙上的影子，并为这些影子命名，因为他认为，自己看到的影子就是现实。实际上却并非如此。

在某种程度上，由于感官的局限，我们就像这个山洞里的囚徒，只能依赖自己的感知，并不能确切地掌握发生的一切。真实的世界存在于远方和山洞之外。

我们用眼睛来观察世界。人类眼睛的底部有一个叫作视网膜的器官，它可以捕捉外界的图像，但视网膜上的图像是上下颠倒的。接收了图像后，大脑便想：这不是世界真实的样子。于是，大脑就帮我们把图像再正过来，否则我们就没办法看到我们现在所看到的东西了。

虽然大脑非常强大，但它也会遇到一些问题。你不能总是相信你的大脑，也要对看到的东西多加思索。你对事物的看法不同，事情本身就会随之变得不同。你可能已经听过了盲人摸象的故事：如果找来6个盲人，让他们各自试着描述一头大象，那么一共就会有6幅截然不同的画面。有人认为大象像一把扇子，有人觉得像一条蛇，还有人说像一堵墙。他们每个人都有自己的观点。科学家要做的就是把大家从不同角度得到的信息都收集起来，从而描绘出一个更接近真相的全貌。其实，我们在某一时间点所掌握的信息从来都只是真相的一部分，但我们总以为自己已经知道了所有的真相。这就是为什么人类必须对周围的一切事物、每一条新的信息都保持开放的态度，因为只有这样才能不断地提高我们对世界的认识。

Since our senses have limitations,we are using machines to transform unperceivable information into something we can either see or hear.The use of instrumentation can expand on human senses.In conclusion,what I’m trying to say here is that there are many,many more things happening in this universe that even with all our senses we still can’t see or hear.

The role of thinking and brain interpretation of the information

Another key is our ability to think.We use our brain to make sense of all the information we gathered.One way is deduction,which goes from theory to hypothesis,and then to observation,and finally to confirmation.This way of thinking is historically brought up by philosophers like Aristotle.Another way of thinking is like Sherlock Holmes.We go from observation like a detective,noticing a pattern,forming a hypothesis,and finally making a theory.

So now I’m going to talk about an allegory.Socrates describes a person who has lived chained facing a blank wall of a cave all of his life.The person watches shadows projected on the wall from objects passing in front of a fire behind him and give names to these shadows.The shadows are this prisoner’s reality rather than accurate representations of the real world.

In some way,due to our limited senses we are like a prisoner in the cave.We don’t know everything exactly because we only know our perceptions.The real thing is what happens far away and outside the cave.

We have eyes to see the world.At the back of the eye there is a retina to capture the image.But inside the eye on the retina,the image is received upside down.The brain is saying,no,this is not correct and then it flips the image right-side up.Otherwise,we will not be seeing what we are really seeing.

The point is that though the brain is very powerful,it does have some problems.You can’t always trust your brain,and you also have to reflect a little bit more on what you see.You probably have already heard about this story before: if you take six blind people and ask them to describe an elephant,then they will all have six different descriptions.Some of them think the elephant is a fan,or a snake,or even a wall.Each one of them has their own perspective.What we scientists are doing is to take all of that information from everybody’s different perspectives to come up with a picture that is closer to the truth.What we actually know at a point in time is only part of the truth,yet we always think we know all of the truth.That’s why it is imperative for us to stay open to everything around us,every new piece of information,in order to always improve our understanding of the world.

2021年8月25日，博江盟在北京天文馆作科普讲座

科学和技术

科学与技术有什么区别？科学是关于物质和自然世界的知识，科学规律则被假定为永不改变的定律。技术则不同，技术是对科学知识的利用，能够创造出许多有用的东西。在科学世界中，科学家着重探索的是事物的基本性质。例如，当谈到空气时，科学家们会去研究空气怎样流动，空气的温度、气压和空气密度等。就其本身而言，这些概念有时看起来很有挑战性，甚至难以理解。但是如果我们面临工程建设的考验，要试图做出一些既实际又好用的东西时，科学知识的基础就是重中之重。如果你想成为一名杰出的工程师的话，你就必须勤奋学习，了解非常丰富的科学知识。

将科学应用到现实生活中、创造出一个能够真正良好运转的东西是一个复杂的过程。工程方案可能会多种多样，任何微小的设计变化都会对其性能产生不同的影响。就拿折纸飞机来举例吧。假设我们用相同的纸来制作飞机，在同一个房间里试飞，所有测试条件都非常相似，但每个人折出来的纸飞机都不一样。有的纸飞机设计不同，而有的设计相同的纸飞机又在折叠的方式上有出入。因此，它们在飞行中的表现也各有千秋。如果你想成为一个优秀的纸飞机工程师，制作出飞得最好的纸飞机，那么首先就必须了解纸飞机能够飞起来的科学原理。所以，你必须学习掌握丰富的科学知识。

Science and technology

What is the difference between science and technology? Science is knowledge about the physical and natural world whose laws are assumed to never change,that they stay the same whenever and wherever.Technology is a different matter;it uses scientific knowledge to create something useful.In science we will focus on understanding some fundamental properties such as air flow,air temperature,air pressure or air density,etc.By themselves,these concepts sometimes seem challenging to understand.However,when we are faced with engineering challenges to make something that actually works well,the scientific knowledge will be very useful.If you want to be an effective engineer,you will have to study diligently and know a lot about science.

Applying science to create a thing that actually works well in the real world is a complex process.There are many engineering solutions available but only one physical world where this object will perform.Any small design changes will have an impact on its performance.For example,let’s make a few paper airplanes and have them fly in the same room.We use identical sheet of paper to make the airplanes and because we are test-flying them in the same room,the testing conditions are very similar.The paper airplanes that were produced are not all identical,some of which were made with different designs and others with the same design were not folded exactly the same way.Consequently,they do not fly the same way.Hence,to be a talented paper airplane engineer and produce the best flying paper airplane,you really need to understand the science of why something can fly.That’s why you have to learn a lot about science.

好奇心和好习惯都很重要

现在让我们来聊聊好奇心。随着年龄的增长，人的好奇心通常会变得越发枯竭。一个美国女孩儿曾赢得了美国宇航局为火星探测器取名的大赛——她为它取名“好奇号”，就是被送到火星上的好奇号火星车。这个女孩儿在当时只有12岁，她不仅赢得了命名比赛，还为我们留下了这样一句话：“好奇心是一种永恒的火焰，燃烧在我们每个人的心中……它是一种强大的力量。没有它，就不会有今天的我们。好奇心是推动我们在日常生活中前进的激情所在。在好奇心的驱动下，在提高和探索中，我们成为探险家和科学家。”这话说得再好不过了。

除了好奇心之外，其他方面的技能同样需要得到培养。想在一门学科上有所建树，我们不能只依靠好奇心，还需要保持专注并持续努力。这是一种叫作“坚韧”的人类品质。要做到这一点有个诀窍，叫作“习惯”。在习惯的帮助下，所有的工作和任务都不再是一种负担。如果你每天都有作业要做，那么你要做的就是把完成作业变成一种习惯，这样一来你就不会再去为它烦恼，而只是去做就可以了。当一件事成为一种习惯的时候，你对它的好恶也就不复存在。你只是在遵从一项习惯罢了。

所以，年轻人要尽早地养成一些好习惯，如完成作业、锻炼身体、先工作后玩耍、勇于承担责任、在机会面前积极主动。除此之外，还别忘了要劳逸结合，好好吃饭。不要害怕思考那些经常让你感到困惑的事。永远记得，要保持积极主动、思想开放！

Curiosity and habits both matter

Now let me talk a little bit about curiosity.As people grow older,they usually get less curious.An American girl has won the contest to name the rover that was actually sent to Mars by NASA: “Rover Curiosity”.This girl was only 12 years old at that time,and not only did she win the competition to name the rover,but has also left us with this inspirational remark: “Curiosity is an everlasting flame that burns in everyone’s mind...It is such a powerful force.Without it,we wouldn’t be who we are today.Curiosity is the passion that drives us through our everyday lives.We have become explorers and scientists with our need to ask questions and to wonder.” I think I could not do a better job to put this in other words.

Curiosity is very important but to be effective one has to also develop other skills.You can be curious about one subject,but to be good at it you will need to keep focused and work hard.You can call this resilience.There is a trick for that,actually,which is called habit.Habits will help you by not having to decide every time to work hard at something.For example,if you have to do your homework every day,what you need to do is to make it a habit,then you won’t think about it anymore as you just do it.When it becomes a habit,your liking or disliking doesn’t exist anymore.You just do it.

It is important for young people to have a few good habits,such as doing your homework,practicing sport but also working before playing or taking responsibility and initiative.Don’t forget to live a balanced life by eating well and exercising often,and don’t be afraid of thinking over things that have confused you.Always remember to be proactive and have an open mind!