Theories and speculations

Quantum Truth

Science and Maths have a lot to say about truth, but apparently little to say about care and compassion. Scientific truth has always had an unusually clear and unambiguous status in Western thought. Most current philosophical approaches recognise the existence of scientific truths. Some rationalists rely on the ultimate existence of scientific fact, even if the fact is as yet unknown. Meanwhile the behaviour of scientists is held under less scrutiny than that of other parts of society. Scientists grapple with the moral implications of what they do, but rarely use moral arguments to limit their investigations. They often do things that would be considered to be wrong or criminal if other people did them. There is some debate about whether they should do these things or not, but little debate about the factual or objective status of the knowledge they develop.

Quantum theory however places some doubt on this whole approach. Quantum theory tells us many strange things, but the most important thing it tells us is about the movement of particles. If you shine a light source from one side of a gap onto a surface on the other side you can tell the light travels in waves because it is divided into a bar pattern, which is created by the wave motion as the light passes through the gap. This is GCSE physics. If you direct particles at a gap and place a detector on the other side you get a similar bar pattern, indicating that the particles also travel in waves, like light. This seems unsurprising, except that when you observe a single particle continuously it travels in a straight line and not as a wave at all. The observation of the particle changes the nature of its motion completely, and alters the outcome of the experiment. It shouldn’t happen, but it does. Particles have a wave motion, except when directly observed. We see the effects of the wave motion on the detector, but the instant we observe closely the particles travel in a straight line. We don’t see the wave motion any more. More confusingly, waves move in a body, but particles don’t. Each particle has its own wave motion. This means that we can’t rely on the movement of a ‘body’ or group. A single particle can theoretically be anywhere, since we cannot know its direction or speed of travel, and its existence can therefore only be described as a probability. As Brian Cox says, the consequence of this is that anything that can happen does happen. Using quantum rules physicists can work out the probability that any particle will be anywhere. However, quantum physics deals only in probabilities.

This is the reason for the strange story of Schrodinger’s cat, the purpose of which is to demonstrate what quantum laws imply for storytelling. The imaginary scenario is that the cat is placed in a box with a radioactive source which emits lethal particles unpredictably and at random, and which will kill the cat. The lid is then closed. The cat’s life and time of death then become a number of probabilities which are all real, and it is therefore possible to consider that the cat is both alive and dead. The story has multiple outcomes and both object and fact are erased and replaced by a range of probability.

Quantum physics therefore has fatal implications for the status of facts, because it turns facts into probabilities. Everything can happen. This consequence of the observation of the movement of particles is comprehensible according to ordinary logic, but the disappearance of the wave motion at the instant of detection is less easily understandable. It is as if a linear movement is created by observation, and that is exactly what does happen. One way to explain it is to say that every instant of the particle’s movement is like the tangent of a curve, and at any one instant we only see that tangential line. Because of the nature of our observation we are not able to ‘track’ the particle, and only see its imaginary movement before and after the moment of observation. This tells us as much about our brains as it does about particles. It is why human beings observe a straight line, but science observes a wave. The particle therefore has two motions – its observed tangential direction at the moment of observation and its wave movement, which can be detected but which remains unobserved and unknown.

While this might seem to be a strange account of reality – Einstein himself only accepted it with reluctance – it is oddly consistent with a world view which says that truth is different to a fact or an object. Firstly, it helps us to explain and understand why we observe objects as factual and solid when in fact they are in a constant state of flux and change. And secondly it explains why reality is not a linear objective story but a moment of interaction. Although we were discussing human emotions above, the parallel with that observation and the observations of quantum physics are more than just an analogy. They are different languages approaching the same unstable reality where facts and objects are not as solid as they seem to be.

As we have seen, maths is central to Quantum theory, because everything has a probability as a form of existence. It is almost as if all existence is now mathematical, and it is certainly the case that any prediction has a mathematical form, as indeed (and more strangely) does the probability of something having happened already. In this way, all action is governed by probability and compassionate (and evil) action is mathematical in the sense that it is a human interaction with probability.

So the rule of probability has direct implications for the way we tell stories, and in a closely connected way for what and how we remember.

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