Friday, July 09, 2010

Some Reflections on nothingness

I believe that the chief obstacle to the adoption of softwarephysics by the IT community has been a deep-seated nagging feeling that, since software is not “real”, how can we possibly apply concepts from physics and the other sciences to software? That is why I have tried to show in many of my previous postings that, thanks to 20th century physics, there really isn’t that much “real” stuff left out there in the physical Universe, at least not “real” in the sense that most people commonly think of when interacting with the things in their immediate surroundings. Mankind has always been fascinated with the “real” and the “unreal”, and that goes for physicists too. So once you get used to physics describing the behavior of “real” things, like electrons, with effective theories like QED that make heavy use of “unreal” things like virtual photons, I claim that it is not that much of a stretch to extend these same ideas of “real” and “unreal” to the behavior of the “unreal” substance we call software. From a positivistic point of view, QED makes incredibly accurate predictions of the behavior of both the “real” electrons and the “unreal” virtual photons, so who cares if these poor little particles have to constantly compute the results of an infinite number of Feynman diagrams just to figure out how to dance about for us? After all, software is constantly doing the same all the time.

I just finished nothingness – The Science of Empty Space (1994) by Henning Genz, which is a good popular study of such things. In nothingness, Genz takes an historical approach to chronicle mankind’s fascination with the concept of a vacuum composed of true nothingness and describes how things have come full circle in our thinking on the matter. Beginning with Aristotle’s concept of horror vacui, the idea that nature abhors a vacuum, he goes on to describe how the early atomists, like Leucippus and Democritus, required a vacuum, or a true void, for their unchanging atoms to bounce around in and to form the new combinations that produce an apparently changing Universe from apparently unchanging atoms. But that was not the norm. Throughout most of historical time, people really did believe in Aristotle’s proposition that a vacuum was impossible to create. This was quite understandable based upon common sense observations. For example, when you suck on a straw, liquid immediately rises into the straw to prevent the formation of a vacuum, and consequently, it was thought that horror vacui was a fundamental law of the Universe that could not be overcome. However, in 1644, Torricelli showed that it was indeed possible to form a vacuum simply by filling a closed glass tube with mercury and inverting the tube in a basin of mercury. Torricelli found that the mercury in the inverted tube dropped to a height of about 30 inches, leaving a vacuum clearly visible in the upper portion of the closed glass tube. Torricelli proposed that it was the weight of the air overhead that forced the mercury up into the inverted tube and that 30 inches of mercury had a weight equivalent to that of the weight of the air overhead. It was not that nature abhorred a vacuum, it was simply that the weight of all that air overhead naturally forced air or any other freely moving fluid into any container trying to become a vacuum.

But was Torricelli’s vacuum a true nothingness? Recall that in the late 19th century physicists discovered the effects of black body radiation and in the early 20th century they found the photons that comprised the black body radiation. It was found that whenever you heated a body or an enclosure above absolute zero, it naturally radiated electromagnetic energy, so even if you were able to remove all the atoms from an enclosed space, the space would still be filled with photons bouncing around within the enclosure, constantly being emitted and absorbed by the walls of the enclosure. The only way to get rid of the photons and attain a true nothingness would be to reduce the walls of the enclosure down to absolute zero, which the third law of thermodynamics unfortunately prohibited. However, it is possible to get the walls of the enclosure down to a temperature very close to absolute zero, and consequently, to get the population of black body photons within the enclosure down to an arbitrarily small number, and in the limit, essentially remove them all. But would this now complete vacuum provide a true nothingness? Not quite. As we learned in The Foundations of Quantum Computing, the quantum field theories of QED and QCD which form the Standard Model of particle physics, tell us that a vacuum is still filled with fields that are subject to quantum fluctuations. In quantum field theory, everything is a field and these fields are observed as matter particles like electrons, quarks, and neutrinos, and also as force-carrying particles like the photons of the electromagnetic force, the gluons of the strong nuclear force, and the W+, W-, and Z0 particles of the weak nuclear force. So even in a complete vacuum, with all atoms and black body photons removed, these fields are still constantly fluctuating and creating “unreal” virtual particles that borrow energy from the vacuum. “Real” particles are simply “unreal” virtual particles that happened to have latched onto some “real” energy, rather than borrowed energy from the vacuum. But recall that from Noether’s theorem energy is just a conserved quantity stemming from the symmetry of the laws of the Universe with respect to time. According to Noether’s theorem, all the interactions in the Universe will behave as if there is a conserved thing we call energy, so long as the laws of the Universe do not change with time. Thus energy is a very positivistic concept based upon how things are observed to behave within the Universe. Energy is like a set of double-entry accounting books that ensure that all energy debits have corresponding energy credits. But does that mean energy is “real” or is it just another form of accounting information? If we misplaced the accounting books of a large corporation for a single day it could still transact business for a short time without the accounting books even existing. So remember that the difference between the “real” and the “unreal” gets rather murky in this quantum mechanical physical Universe that we all live in.

The important point is that Aristotle seems to have been right all along. It really does seem impossible to create a true nothingness in our physical Universe. This might be a remnant characteristic left over from a time before the origin of our current Universe. Recall that the current thinking is that our physical Universe resulted from a quantum fluctuation in an extended infinite multiverse that exploded into our current Universe all on its own. This quantum fluctuation rapidly expanded and cooled through a process of Inflation, as the formation of the Higgs field that gives matter particles their masses, broke the symmetry of the original high-temperature quantum fluctuation, yielding a nearly flat physical Universe made of “nothing”, with no net momentum, angular momentum, or mass-energy to speak of. Strangely, this symmetry breaking created a physical Universe made of “nothing”, but at the same time, seemingly incapable of producing a true nothingness of its own! Perhaps this apparent paradox simply stems from a fundamental philosophical misunderstanding. Perhaps the answer to the age-old question of why is there something rather than nothing might just be another question – what leads you to believe that there is something in the first place? As we saw in Is the Universe a Quantum Computer?, perhaps the physical Universe is really just a nothingness of intangible information constantly calculating how to behave. So as we have seen, at the quantum level, the concept of “reality” gets pretty murky. Perhaps this all-pervading illusion of reality that we all rely upon so heavily in our day-to-day life is just another emergent behavior of our Universe, and should really be described by the complexity theory we explored in The Origin of Software the Origin of Life.

So given that our physical Universe is made of “nothing”, but at the same time, is still capable of being studied by physics and the other sciences, doesn’t it make sense that the Software Universe in which we all reside might be capable of the same? Like the physical Universe, the Software Universe is not that “real” either. It is simply composed of the froth of CPU processes currently running on the 10 trillion currently active microprocessors scattered throughout our Solar System. If each microprocessor is running about 100 concurrent CPU processes, that comes to about a quadrillion CPU processes in all. As an IT professional, those quadrillion CPU processes are just as “real” to me as anything else in this Universe, and tend to impact my life a lot more than many of the other “real” things out there in the physical Universe. There is nothing like spending a holiday weekend as the MidOps Primary, while trying to clean your carpets with a Rug Doctor between pages, to drive home that point.

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Steve Johnston