Concepts explained
Is There a Special Atom of Life? — The Blueprint Is an Order of Ordinary Atoms
The atoms of life are the same as in rock and air. Yet a blueprint really exists: DNA. Not one special atom but billions of ordinary atoms in order, carried on not because it never disappears but because it keeps being copied. To close the series, the film's lines are sorted one by one into science and imagination.
The director's question
The wave-gathering device in the film was also, at first, a device for gathering this life atom. If the body scatters but the life atoms could be gathered again, might we meet that person once more? Looking back, I think the idea came from not wanting to forget. I know memory and information are not the same, and that memory is always imperfect. Still, people hold on to memory. So do I.
Science's answer — the blueprint is an order of ordinary atoms
The atoms of life are not special: , hydrogen, oxygen, , the same as in rock, air and sea. Swap an atom from your body for one from the ocean and no one could tell. As part 4 showed, atoms of one kind are exactly alike.
But a blueprint really exists: , which records how to build a body and passes it to the next generation. Not one special atom, though, but billions of ordinary atoms in a particular order: a long chain of four kinds of letter, whose order is the content of our . As part 1 said, information lives not in atoms but in arrangement. DNA is the clearest example.
DNA is not eternal either; when the body dies it scatters. But while alive it copies itself and hands the copy on. Life's information continues not because it never disappears but because it keeps being copied. There was no deathless atom such as I first imagined, but there was an arrangement that copies itself before it disappears.
Life feeds on order
Part 6 said increases in things that happen by themselves. Yet life keeps astonishing order inside the body. Does it break the law? No: it keeps inner order by increasing the disorder around it even more. That is what eating, breathing and giving off heat are: taking in well-ordered food and sending out scattered heat and carbon dioxide. Life keeps a small order in the middle of a universe whose disorder grows.
A little further in
Those who asked first
Long ago people believed life held a special force absent from ordinary matter, an idea called ; the substances living things make could be made only by living things. In 1828 the German chemist Wöhler made urea, a substance in urine, from ordinary materials in the laboratory, and the belief began to waver. It did not fall at once but gave way gradually over the following decades as similar experiments piled up.
Schrödinger, famous for the cat of part 4, wrote a small book late in life, What Is Life? Before anyone knew DNA carries hereditary information, he foresaw that it must be written in a crystal-like structure of atoms arranged without repeating pattern. He also wrote that life feeds on negative entropy; the physicist Brillouin later shortened that to .
Among those drawn into science by that book were Watson and Crick, who in 1953 showed that DNA is a double helix of two twisted strands. The decisive clue was an X-ray photograph taken by the British scientist Rosalind Franklin. The photograph was shown to Watson without her knowledge, and Franklin died before she could share in a Nobel Prize.
What we do not know yet
How ordinary atoms first began copying themselves, how life began, is still unknown: the mystery left open in part 2. A leading idea is that another self-copying molecule came before DNA, but no one has yet made life from scratch in a laboratory.
In the film
The film's idea began with a special substance, a life atom, and in the finished film became pattern and wave. In one person's head it walked again the road science took from vitalism to DNA. The film's line, “A life can leave a pattern,” is the sentence that arrived at the end of that road.
The film began where science ends. To close the series, here are the lines of the film's physicist, David, sorted one by one.
David's lines: how much is science?
| David's line | Verdict | In one line | See part |
|---|---|---|---|
| In quantum physics… it might be both | Science for particles, imagination for people | Two states at once belongs to the very small, cold world; even Schrödinger said it was absurd for a cat | Part 4 |
| Until we look for sure, it isn't settled as one thing | Science in principle, interpretations differ | Confirmed by experiment for tiny particles, but physicists disagree on what it means | Part 4 |
| It didn't disappear. It spread out | Science | The atoms of a body are not lost; they scatter and become part of trees, seas and other people | Parts 2, 3 |
| The same energy, a different form | Science | Energy is never lost, only changes form | Part 2 |
| Nothing ever completely disappears | Science in principle | Physics holds that information is not lost either, though black holes are still argued over | Part 6 |
| A life can leave a pattern. In light, in air, in stone | Traces are science; a whole person is imagination | Photos and the carbon of a breath really remain; a person's memories and mind do not remain whole | Parts 1, 3 |
| If that pattern remains as waves… in theory it can be traced completely | Imagination | Information may remain in principle but is scrambled beyond reading, and a person's ripples are lost a hand's breadth away | Parts 5, 6 |
| This doesn't bring anything back. It only shows where it went | A line the film draws itself | The character states the border between science and imagination | All |
| It could gather them too. But it's still unstable | Imagination, but plausible | Gathering what has scattered goes against entropy, so of course it is unstable | Part 6 |
Science means confirmed by experiment and observation; science in principle means right in theory but impossible in practice; imagination means a scientist's or the film's.
The question that remainsOf the patterns I will leave, which will someone copy and carry on?