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  • Life is fundamentally different from dead stuffor is it?

  • Physicist Erwin Schrödinger defined life this way:

  • Living things avoid decay into disorder and equilibrium.

  • What does this mean?

  • Let's pretend that your download folder is the universe.

  • It started orderly and got more and more chaotic over time.

  • By investing energy, you can create order and clean it up.

  • This is what living things do.

  • But what is life?

  • Every living thing on this planet is made of cells.

  • Basically, a cell is a protein-based robot too small to feel or experience anything.

  • It has the properties we just assign to life:

  • it has a wall that separates it from the surroundings, creating order;

  • it regulates itself and maintains a constant state;

  • it eats stuff to stay alive;

  • it grows and develops;

  • it reacts to the environment;

  • and it's subject to evolution;

  • and it makes more of itself.

  • But of all the stuff that makes up a cell, no part is alive.

  • Stuff reacts chemically with other stuff, forming reactions

  • that start other reactions which start other reactions.

  • In a single cell, every second several million chemical reactions take place,

  • forming a complex orchestra.

  • A cell can build several thousand types of protein:

  • some very simple, some complex micromachines.

  • Imagine driving a car at 100 km/h while constantly rebuilding every single

  • part of it with stuff you collect from the street.

  • That is what cells do.

  • But no part of the cell is alive; everything is dead matter

  • moved by the laws of the universe.

  • So is life the aggregate of all these reaction processes that are taking place?

  • Eventually, every living thing will die.

  • The goal of the whole process is to prevent this by producing new entities;

  • and by this, we mean DNA.

  • Life is, in a way, just a lot of stuff that carries genetic information around.

  • Every living thing is subject to evolution,

  • and the DNA that develops the best living thing around it will stay in the game.

  • So, is DNA life, then?

  • If you take DNA out of its hull, it certainly is a very complex molecule,

  • but it can't do anything by itself.

  • This is where viruses make everything more complicated.

  • They are basically strings of RNA or DNA in a small hull

  • and need cells to do something.

  • We're not sure if they count as living or dead.

  • And still, there are 225,000,000 m³ of viruses on Earth.

  • They don't seem to care what we think of them.

  • There are even viruses that invade dead cells and reanimate them

  • so they can be a host for them, which blurs the line even more.

  • Or mitochondria.

  • They are the power plants of most complex cells and

  • were previously free living bacteria that entered a partnership with bigger cells.

  • They still have their own DNA and can multiply on their own, but

  • they are not alive anymore; they are dead.

  • So they traded their own life for the survival of their DNA,

  • which means living things can evolve into dead things as long as it's beneficial

  • to their genetic code.

  • So, maybe life is information that manages to ensure its continued existence.

  • But what about AI (artificial intelligence)?

  • By our most common definitions, we are very close to creating artificial life

  • in computers.

  • It's just a question of time before the technology we build gets there.

  • And this is not science fiction, either;

  • there are a lot of smart people actively working on this.

  • You could already argue that computer viruses are alive.

  • Hm, okay. So what is life, then?

  • Things, processes, DNA, information?

  • This got confusing very fast.

  • One thing is for sure:

  • the idea that life is fundamentally different from non-living things

  • because they contain some non-physical element

  • or are governed by different principles than inanimate objects

  • turned out to be wrong.

  • Before Charles Darwin, humans drew a line between themselves and the rest

  • of living things; there was something magical about us that made us special.

  • Once we had to accept we are like every living being, a product of evolution,

  • we drew a different line.

  • But the more we learn about what computers can do and how life works,

  • the closer we get to creating the first machine that fits our description of life,

  • the more our image of ourselves is in danger again.

  • And this will happen sooner or later.

  • And here's another question for you:

  • if everything in the universe is made of the same stuff,

  • does this mean everything in the universe is dead

  • or that everything in the universe is alive?

  • That it's just a question of complexity?

  • Does this mean we can never die

  • because we were never alive in the first place?

  • Is life and death an irrelevant question and we haven't noticed it yet?

  • Is it possible we are much more part of the universe around us than we thought?

  • Don't look at us; we don't have any answers for you.

  • Just questions for you to think about.

  • After all, it's thinking about questions like this that makes us feel alive

  • and gives us some comfort.

Life is fundamentally different from dead stuffor is it?

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生命の始まりとは?死は本当に存在するのか?(What Is Life? Is Death Real?)

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    Eating   に公開 2015 年 01 月 31 日
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