Uncertainty

Jedenfalls bin ich überzeugt, dass der nicht würfelt. (At any rate, I am convinced that He [God] does not play dice.) [86]

Not long ago (less than a lifetime) some scientists and philosophers (Niels Bohr and others) argued that some things must be able to go different ways even when the starting conditions are exactly the same.

Albert Einstein (originator of the theory of relativity), who had already shown that Newton was only partly right, did not like this idea and argued that 'He does not play dice'.

Bohr won the argument by using the 'Heisenberg Uncertainty Principle' that says that you can never accurately know both a particle's position and its momentum. But Einstein was never happy with the outcome.

Maybe some events in the universe can jump different ways, given exactly the same starting conditions. We know from chaos and complexity theory that even a tiny event can rapidly multiply to make huge changes in everything. If the tiniest thing is unpredictable then we are wrong in believing we can predict everything.

Events and conditions over which you have no control influence every event in your life. If you run out on the road a car might kill you but only if one is there at that second and only if the driver can't stop and only you are hit in a certain way.

There is no complex decision you can make that might not turn out unexpectedly. We can reduce this uncertainty by knowing as much as possible about the related events but we can never fully predict how related events will flow.

In other words the uncertainty principle says we can never know everything about the future. Of course in life we find there are lots of things too complex to predict, from horse races to our own future. But the uncertainty principle seems to say that some aspects of the future are unknowable even if we could get past the complexity.

It is important to know how much we can't know (is impossible to predict). It must be very small. If a lot was unknowable, we couldn't rely on gravity working tomorrow or things being where we left them, or anything working the same way twice.

We are now in the information age. When we collect and try to use information we are sending or getting a message. When we look at, feel, smell or hear anything, it is sending us some kind of message.

At a party, if you sit in a circle of people and whisper a message to the person next to you, then each person whispers it to the next, by the time it gets back it is quite different. Until we had radios telephones and computers people assumed that all mistakes in messages were due to mistakes that people made (because they usually were). Then we discovered that no matter how hard you try you can never eliminate all mistakes.

When a message is sent by any method it has two components: Signal (the data being sent) and Noise (everything else; like the fuzzy bit in a TV picture, the crackle on the radio). We can get rid of a lot of the noise by improving our machines and methods but it turns out that we can never eliminate it completely. Information theory attempts to describe these relationships.

Of course we always have known that messages can get confused or changed with repetition and so we have lots of natural checks to indicate that they may have got garbled. Rhyming in poems and songs are obvious examples. Natural grammar appears to be programmed-in by our genes and of course we invented pictures and writing.

Now when we want to send an exact message, for example from one computer to another, we know to send check bits that reveal if it has mistakes, so the parts with mistakes can be sent again.

It turns out that the little bit of noise we can't ever get rid of is similar to our uncertainty about atomic particles. The only way we know where particles are is because of the forces that they seem to exert on each other. These can be described as messages they exchange. Some think that these are just different ways of looking at the same thing.

This absolutely unknowable bit of a message is a measure of the uncertainty in our universe, the proportion of events that we can't ever predict with certainty. And it looks like this might be a property of our universe that might be different in other possible universes. So again it is related to us being here.

Observing events is receiving their message. Some messages sent by sub-atomic particles have interesting feature. They can remain uncertain until they are read. Of course you immediately say, 'What's so unusual about that? Every message is uncertain to the receiver until it is read'.

But in the case of a quantum particle the message is not written until it is read! It is uncertain to the sender too. This can be demonstrated by making a quantum pair then observing one half. This causes the other to change state. More bizarre, physicists believe that reading a message from one half determines the state of the other anywhere in the Universe; instantaneously. The observer changes the message.

Our culture or spring often takes up scientific ideas just as science uses ideas from our culture. Several authors and filmmakers have explored the idea that observing events interferes in them; changes their outcome. The act of observing can be subtle or crude, depending on how the message is used afterwards and how aware the observed is of the observer. Are messages sent back; is there a conversation; is it passed on to others; is it garbled or twisted?

In computing and the media we make the distinction between one-to-one messages and one-to-many messages (broadcast). In the first case I expect acknowledgement; some kind of reply; or I may conclude that my message was not read. In the second I assume many will read it and take it or leave it. The message I send, and the impact it has on me, will be quite different depending on whether it is broadcast or sent selectively to others we know. We might be slobs at home but get dressed-up and brush our hair to go out.

Awareness that they are observed, or could be observed, changes the behaviour of the observed. Newspapers television, radio and the Internet change the events they report. Journalists now change the outcome of wars; not only when they stage news stories or give strategic information to the enemy; but also when they behave ethically and responsibly. Their impact will be greater the more obvious is their presence and the more they interfere.

Even in disguise and using hidden cameras, the publication of a story causes a change. For example the observed may learn that hidden cameras might be used or that others respond to their actions (without knowing why) and change their behaviour. Journalists have increasing impact because their messages are broadcast increasingly quickly and widely and the observed quickly realise that they are observed.

Because of their importance, you can see how small random changes (noise) in messages could easily change the future. If the Universe was replayed from exactly the same starting point, some messages would be slightly changed and some events and behaviour would not be repeated.

We are just starting to have the concepts within our society and to get the words to talk about these things (uncertainty, chaos, information theory and so on). You need to read about them and think about them if you are going to be educated and informed and to have any chance of understanding the modern conception of the universe.