Physics and Reality

I have just got back from a few days in beautiful Vancouver where I got lucky because after almost five months of really terrible weather it turned sunny and gorgeous, the city rising like a magical Atlantis above the somber green of a devastated Stanley Park. There, some 6,000 of the old stately trees that once towered over seemingly timeless trails have been felled by ferocious winter winds and lie twisted and mourning, belly up, so to speak. Another hundred years, and maybe it will be as it once was.

In Vancouver it is easy to feel overwhelmed by the grandness of visible nature, and on this trip, I happened to be reading a book about quantum physics by the late Richard Feynman called Six Easy Pieces, and so I also felt overwhelmed by the invisible mysteries of nature. Feynman won a shared Nobel Prize for physics in 1965 and taught at California Institute of Technology until 1987, and was by then a quixotic, exuberant, and beloved teacher whose life was itself a manifestation of true philosophy: wonder incarnate. He mostly taught physics to advanced graduate students, but for 1962-63 Caltech asked him to explain modern physics to undergraduates, and so in place of the usual stuff about levers, laws of motion, conservation of energy, and so on, he introduced them to the weird world of quantum physics, which is all about the behaviour of atoms,  the many smaller particles within atoms, and how almost nothing in this micro world behaves as things do in the everyday macro world we all know in the form of water, rocks, trees, chairs, tables, and so on. From the very start, this fact shook a lot of people up.  

In a famous year-long debate of 1903-04 that some say he lost, G.K. Chesterton argued for spirituality and the existence of God against the scientist Blatchford, who argued for materialism and atheism. It so happened that long after the debate Heisenberg published his “Uncertainty Principle” the gist of which was that we cannot predict the behaviour of sub-atomic particles because if we know their position with certainty we cannot know their momentum, and vice versa. Below I will try to suggest why this is true for any readers who, like me, may have referred to “the Uncertainty Principle” knowingly a few times in their lives in the secret hope of impressing a listener, but who, again like me, didn’t really know exactly why it was so. At any rate, when Blatchford read about the unpredictability of matter and energy (both apparently the same thing at this level, where “particles” are really bundles or “quanta” of energy), he published a final confession that due to the discovery of the Uncertainty Principle he had now become “a spiritist.” By this he meant that as no one could or would ever be able to predict the most fundamental behaviour of matter, only God could know the outcome of reality.

Something else must be added. The quantum revolution in physics had taken off by the 1920s and is known today as the New Physics, the Old Physics being the one must of us learned (and still learn) in high school, comprised of physical laws and equations that continue to govern the macro world we live in. Despite this fact - I mean that most of us will never see or hear about a quantum particle in our entire lives, and that Newton’s laws will always govern everything we do – the much misunderstood themes of “relativity” and “uncertainty” in the new physics almost immediately began to reshape public opinion about nature. Soon, sophisticated opinion insisted that “reality” is unknowable (and leapt to the conclusion that therefore truth is unknowable) even though quantum reality is not one that anyone could ever know, or live in. But to close for now, here is the best explanation I can give of why there is an Uncertainty Principle in the micro world:

Werner Heisenberg first presented his “Uncertainty Principle” in a letter to physicist Wolfgang Pauli in 1927 stating that in sub-atomic physics it is impossible to know the exact position and the exact momentum of an object at the same time. The reason for this is that to know something about any particle, smaller particles must first be bounced off it, which then bounce back to the measuring device. This hitting and bouncing is so small at macro levels, that we say it is insignificant. Practically speaking, we could bounce all sorts of different things off objects to discover what they are like as long as we had a device to record the patterns made by the rebounding objects. To observe a sub-atomic particle, however, we use light which is itself made of packets of energy, or particles called “photons.” At the real-world or macroscopic level when light bounces off an object the reflection tells us exactly where the object is in space and time. But at a sub-atomic level the photons that hit the particle cause it to move significantly, just like a billiard ball hitting another billiard ball, such that although its position may be measured accurately, its velocity will have been altered in performing this measurement of position, so that precise information on its true velocity is lost at the same moment. To know position more accurately is to know momentum less accurately, and vice versa.

This inescapable interference operates only at the micro level, and is of no concern or significance for the real world of macro-objects (anything larger than a molecule) which we can measure pretty accurately and which have always and will always obey Newton’s laws. This means that the fashionable modern penchant for describing the real macro world we all live in as one of uncertainty and relativism as if it also behaved like the micro world,  is a wild distortion of the truth: the macro reality we experience never behaves this way. Its behaviour is certain to an amazing degree of Newtonian absoluteness, and it is plain untruth to argue otherwise.