Is Anything Truly Random?

I hated science lessons at school.  Looking back, it was miraculous that the science curriculum and those that taught it managed to make a subject so fascinating – a subject with such universal appeal to the inquisitive minds of children – so dull.  I imagine my science teachers put this skill to use in their downtime by going to parties and turning all the wine into water.

Bill Bryson expresses a similar concern in his Introduction to A Short History of Nearly Everything.  In writing this book, Bryson produced the grand daddy of popular science books but beyond him there is a wealth of non-fiction science books aimed not just at Physics MSCs, but rather anyone that has a healthy mind and enjoys asking the question “why?”.

Marcus Chown - We Need To Talk About Kelvin Front CoverThe more science I read, the more I appreciate it’s place in the arts alongside philosophy and psychology.  Marcus Chown, in We Need To Talk About Kelvin – What Everyday Things Tell Us About The Universe, attempts to help us rekindle our child-like enthusiasm for intellectual discovery by describing how normal things can prove mind-blowing concepts.  And so on to the question at hand; a question which is seemingly philosophical in nature.

It could easily be argued that nothing is random. Much of human behaviour has been shown to be predetermined by our genes and our behaviour.  A coin toss is caused by gravity, resistance, the velocity and angle of the throw and the detail of the surface it lands on.  One could argue that if these causes could be perfectly simulated then the result could be predicted.  Due to technological limitations we are not able to produce such a perfect simulation but it is a compelling argument nonetheless.

What does Chown say to the question ‘is anything truly random’?  His answer is: “yes, God plays dice”.  What everyday thing proves this according to Chown?  Your reflection in a window.

Imagine looking through a window when the light outside is low.  You can see your reflection in the glass, but you can also see beyond it to the other side of the window.  Let’s say that the glass appears 60% opaque.  So what?  Well, some light is reflecting back and some is continuing through.  This makes sense if light is a wave, like a ripple in a lake spreading out and continuing despite hitting a small floating obstacle.  However, light is also a stream of photon particles, each particle identical.  Commons sense and observation tell us that the overall effect is stable; so how is it that some photons pass through and some reflect?

It took the genius of Einstein to realise that this dilemma was a bomb-shell dropped into the laws of physics.  The only logical answer is that 40% of the particles are being reflected back.  Giving that each photon is identical, each photon has a 40% chance of being reflected and a 60% chance of continuing straight through.  This means it is impossible to predict what a single photon will do when it reaches the glass; it effectively has to ‘decide’ itself.  Unlike the lack of computing power required to simulate a coin toss, predicting the behaviour of a photon when it reaches the glass is not a practical issue.  It is impossible to predict because the photon’s beahviour is completely and utterly random; effect without cause.  It’s not just light either; at the microscopic level, the entire world is governed by chance.

But this is just the beginning of the madness.  Chown goes on to draw further conclusions from this everyday observation.  It can also be demonstrated that light is both a wave and a particle, that a single photon can be in two places doing two things at once, and that particles can break the speed of light by instantaneously influencing another particle at any distance.

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3 Comments

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3 responses to “Is Anything Truly Random?

  1. Is it not possible that the actions of a photon could too be “predicted” if the “causes” could be understood and “perfect simulation” created, were it not for the “technological limitations”.

    I’m no scientist but could the rule of the coin not be extended to the photon? Light is not shone in a vacuum, could there not be infinitesimal conditions (re: the glass, the environment in which the glass stands, the angle, distance and strength of the light being shone [in relation to the glass] etc) that if they could be understood and perfectly simulated, “the results could be predicted”?

    I feel I’m missing something in the argument, but why does the coin offer a compelling argument, and the photon not? Tell me more…

    • With the coin toss, we’re talking about one thing repeated many times with different variables. With the light, we’re talking something repeated many times with identical variables. Each has a stable outcome that can be observed, be it 50/50 heads/tails or 60% opacity.

      Every time someone throws the coin, they exert a slightly different force on it; they maybe spin it harder, throw it higher, or it may land on different parts of the table where the wood varies. These are factors that could potentially be simulated to eliminate any random element from the outcome of a coin toss. It is possible to build a precise enough machine in a stable environment that could always throw a tails.

      The same cannot be said for the light photon. Like the coin toss, we know from the overall effect that some will reflect and some will not. The problem is that each photon is completely and utterly identical. Each has the exact same chemical make-up. There are no infinitesimal changes in the environment then we can measure. They have no will to make a decision whether to reflect or not. There is literally nothing to distinguish between them. Each moves at the speed of light, hits the glass, but some bounce back and some do not. No machine could generate light that would entirely reflect or not reflect, because there is no other way to generate light than, well, generating light.

  2. Pingback: Bill Bryson – A Short History of Nearly Everything | Nonfiction Book Club

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