Determinism

In the early years of the 19th century, science was on a roll. The dark days of alchemy were beginning to give way to the modern science of chemistry as we know it today, the world of physics and the study of electromagnetism were starting to get going, and the world was on the brink of an industrial revolution that would be powered by scientists and engineers. Slowly, we were beginning to piece together exactly how our world works, and some dared to dream of a day where we might understand all of it. Yes, it would be a long way off, yes there would be stumbling blocks, but maybe, just maybe, so long as we don’t discover anything inconvenient like advanced cosmology, we might one day begin to see the light at the end of the long tunnel of science.

Most of this stuff was the preserve of hopeless dreamers, but in the year 1814 a brilliant mathematician and philosopher, responsible for underpinning vast quantities of modern mathematics and cosmology, called Pierre-Simon Laplace published a bold new article that took this concept to extremes. Laplace lived in the age of ‘the clockwork universe’, a theory that held Newton’s laws of motion to be sacrosanct truths and claimed that these laws of physics caused the universe to just keep on ticking over, just like the mechanical innards of a clock- and just like a clock, the universe was predictable. Just as one hour after five o clock will always be six, presuming a perfect clock, so every result in the world can be predicted from the results. Laplace’s arguments took such theory to its logical conclusion; if some vast intellect were able to know the precise positions of every particle in the universe, and all the forces and motions of them, at a single point in time, then using the laws of physics such an intellect would be able to know everything, see into the past, and predict the future.

Those who believed in this theory were generally disapproved of by the Church for devaluing the role of God and the unaccountable divine, whilst others thought it implied a lack of free will (although these issues are still considered somewhat up for debate to this day). However, among the scientific community Laplace’s ideas conjured up a flurry of debate; some entirely believed in the concept of a predictable universe, in the theory of scientific determinism (as it became known), whilst others pointed out the sheer difficulty in getting any ‘vast intellect’ to fully comprehend so much as a heap of sand as making Laplace’s arguments completely pointless. Other, far later, observers, would call into question some of the axiom’s upon which the model of the clockwork universe was based, such as Newton’s laws of motion (which collapse when one does not take into account relativity at very high velocities); but the majority of the scientific community was rather taken with the idea that they could know everything about something should they choose to. Perhaps the universe was a bit much, but being able to predict everything, to an infinitely precise degree, about a few atoms perhaps, seemed like a very tempting idea, offering a delightful sense of certainty. More than anything, to these scientists there work now had one overarching goal; to complete the laws necessary to provide a deterministic picture of the universe.

However, by the late 19th century scientific determinism was beginning to stand on rather shaky ground; although  the attack against it came from the rather unexpected direction of science being used to support the religious viewpoint. By this time the laws of thermodynamics, detailing the behaviour of molecules in relation to the heat energy they have, had been formulated, and fundamental to the second law of thermodynamics (which is, to this day, one of the fundamental principles of physics) was the concept of entropy.  Entropy (denoted in physics by the symbol S, for no obvious reason) is a measure of the degree of uncertainty or ‘randomness’ inherent in the universe; or, for want of a clearer explanation, consider a sandy beach. All of the grains of sand in the beach can be arranged in a vast number of different ways to form the shape of a disorganised heap, but if we make a giant, detailed sandcastle instead there are far fewer arrangements of the molecules of sand that will result in the same structure. Therefore, if we just consider the two situations separately, it is far, far more likely that we will end up with a disorganised ‘beach’ structure rather than a castle forming of its own accord (which is why sandcastles don’t spring fully formed from the sea), and we say that the beach has a higher degree of entropy than the castle. This increased likelihood of higher entropy situations, on an atomic scale, means that the universe tends to increase the overall level of entropy in it; if we attempt to impose order upon it (by making a sandcastle, rather than waiting for one to be formed purely by chance), we must input energy, which increases the entropy of the surrounding air and thus resulting in a net entropy increase. This is the second law of thermodynamics; entropy always increases, and this principle underlies vast quantities of modern physics and chemistry.

If we extrapolate this situation backwards, we realise that the universe must have had a definite beginning at some point; a starting point of order from which things get steadily more chaotic, for order cannot increase infinitely as we look backwards in time. This suggests some point at which our current universe sprang into being, including all the laws of physics that make it up; but this cannot have occurred under ‘our’ laws of physics that we experience in the everyday universe, as they could not kickstart their own existence. There must, therefore, have been some other, higher power to get the clockwork universe in motion, destroying the image of it as some eternal, unquestionable predictive cycle. At the time, this was seen as vindicating the idea of the existence of God to start everything off; it would be some years before Edwin Hubble would venture the Big Bang Theory, but even now we understand next to nothing about the moment of our creation.

However, this argument wasn’t exactly a death knell for determinism; after all, the laws of physics could still describe our existing universe as a ticking clock, surely? True; the killer blow for that idea would come from Werner Heisenburg in 1927.

Heisenburg was a particle physicist, often described as the person who invented quantum mechanics (a paper which won him a Nobel prize). The key feature of his work here was the concept of uncertainty on a subatomic level; that certain properties, such as the position and momentum of a particle, are impossible to know exactly at any one time. There is an incredibly complicated explanation for this concerning wave functions and matrix algebra, but a simpler way to explain part of the concept concerns how we examine something’s position (apologies in advance to all physics students I end up annoying). If we want to know where something is, then the tried and tested method is to look at the thing; this requires photons of light to bounce off the object and enter our eyes, or hypersensitive measuring equipment if we want to get really advanced. However, at a subatomic level a photon of light represents a sizeable chunk of energy, so when it bounces off an atom or subatomic particle, allowing us to know where it is, it so messes around with the atom’s energy that it changes its velocity and momentum, although we cannot predict how. Thus, the more precisely we try to measure the position of something, the less accurately we are able to know its velocity (and vice versa; I recognise this explanation is incomplete, but can we just take it as red that finer minds than mine agree on this point). Therefore, we cannot ever measure every property of every particle in a given space, never mind the engineering challenge; it’s simply not possible.

This idea did not enter the scientific consciousness comfortably; many scientists were incensed by the idea that they couldn’t know everything, that their goal of an entirely predictable, deterministic universe would forever remain unfulfilled. Einstein was a particularly vocal critic, dedicating the rest of his life’s work to attempting to disprove quantum mechanics and back up his famous statement that ‘God does not play dice with the universe’. But eventually the scientific world came to accept the truth; that determinism was dead. The universe would never seem so sure and predictable again.

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Time is a funny old thing…

Today I am rather short on time- the work I have to do is beginning to mount up despite (and partially because) of a long weekend. To most people this is a perfectly good reason to put up an apologetic cop-out of a post to prevent them having to work on it, but for me, it is a perfectly good excuse for my bloodymindedness to take over, so I thought I might write something about time.
As such a strange and almost abstract concept as it is, time can be viewed from a number of perspectives- the physical sense, the thermodynamic sense, and the human sense are the three obvious ones that spring to mind. To a physicist, time is a dimension much like width and length, and is far from unique- in fact there is a large sector of theoretical physics open to the idea that in the big bang there were many millions of dimensions, only 4 of which (3 spacial and one temporal) opened up into the rest of the universe, the other dimensions only existing on a microscopic, atomic scale (which might explain why the quantum world is so plain weird. Hey- I’m no physicist, and the web can probably tell you more). The really special thing about time compared to spacial dimensions to a physicist (among a long list, that are confusing and difficult to describe), is that it is the only dimension with an obvious direction. People often talk of ‘the arrow of time’, but the idea of any other dimension having an arrow is only a sort of arbitrary point of reference (north & south, up & down are only relative to our own earth and so are merely convenient reference points. This idea of time having an irreversible arrow annoys a lot of physicists as there appears to be little, fundamentally, that means we couldn’t travel in time in the other direction- the theory of relativity, for example, shows how fluid time can be. The idea of time’s direction has a lot to do with thermodynamics, which is where the second perspective of time comes from.
Really I am using the word thermodynamic very loosely, as what I am really thinking of is more to do with the psychological arrow of time. To quickly paraphrase what I mean by thermodynamics, the second law of thermodynamics states that the universe’s level of entropy, or randomness, will always increase or stay the same, never decrease, because a more random, chaotic system is more stable. One way of thinking of this is like a beach- the large swathes of sand can be arranged in a huge number of configurations and still seem the same, but if there are lots of sandcastles over it, there is a lot less randomness. One can seemingly reverse this process by building more sandcastles, making the universe more ordered, but to do this requires energy which, on a universal level, increases the universe’s entropic level. It is for this reason that a smashed pot will always have been preceded, but not followed by, the same pot all in one piece.
The thing is, the psychological and thermodynamic arrows of time point in the same direction, and their link on one another is integral. Our whole view of the passing of time is influenced by the idea of events that have irrevocably ‘happened’ and are ‘over’, hence our eternal fascination with ‘what if’s’. We persistently worry about past mistakes, what could have been, and what things were like, but never can be- hence the popularity of historical stories, ruins, nostalgia and grumbling about teenagers. For a better explanation of the various ‘arrows of time’, try Stephen Hawking’s ‘A Brief History of Time’- it is somewhat out of date now and it is fashionable now to think of it as overly simplistic, but it’s still a good source of a grounding in high-level physics
The final, and to me most interesting, perspective of time I want to talk about is deeply linked to the psychological arrow and our thoughts of the passing of time, but brings its own, uniquely relative, view- the human perspective (notice how it is always people I seem to find the most interesting.) We humans view time in a way that, when thought about, paints a weirdly fluid portrait of the behaviour of time. There is never enough time to work, too much time spent waiting, not enough time spent on holidays or relaxing, too much time spent out of work, too little time spent eating the cake and too much spent washing up. There are the awkward pauses in conversation that seem to drag on for an eternity, especially when they come just after the moment when the entire room goes silent for no accountable reason, enabling everyone to hear the most embarrassing part of your conversation. There are those hours spent doing things you love that you just gobble up, revelling in your own happiness, and the bitter, painful minutes of deep personal pain.
Popular culture and everyday life often mentions or features these weirdly human notions of time being so relative to the scenario- Albert Einstein himself described relativity thus: “When you are talking to a nice girl, an hour seems like a second. When you have your hand on a bar of red-hot iron, a second seems like an hour”. In fact, when you think about it, it is almost as if time appears to be a living thing, at least in the context of our references to it. This, I think anyway, is the nub of the matter- time is something that we encounter, in its more thermodynamic form, every day of our lives, and just like pet owners will tend to anthropomorphise their pets’ facial expressions, so the human race has personified time in general conversation (well, at least in the western world- I cannot speak for anywhere non English-speaking as a certainty). Time is almost one of the family- ever-present, ever-around, ever-referred to, until it becomes as human as a long-lost friend, in its own little way.
Finally, on the subject of time, Mr Douglas Adams: “Time is an illusion; lunchtime doubly so”