Life is Like a Box of Timelines

In my last posting Digital Physics and the Software Universe, we covered the idea that our Universe might seem to behave like a large network of quantum computers calculating how to behave, if not in an actual literal sense as the realists would have us believe, at least, perhaps, in a positivistic manner that makes for a good model that yields useful predictions about how our Universe seems to behave. Recall that positivism is an enhanced form of empiricism, in which we do not care about how things “really” are; we are only interested in how things are observed to behave. With positivism, physicists only seek out models of reality - not reality itself. In keeping with that observation, I would like to recommend two offerings on Netflix. Now if you do not currently have Netflix, you can easily stream it for free for 30 days on a trial basis, so I do not feel conflicted about making this recommendation. The first recommendation comes from the Black Mirror series on Netflix that features stories from the dark side of IT. This particular Black Mirror feature is an interactive movie entitled Bandersnatch. The second recommendation is the Netflix series entitled Russian Doll. Both Bandersnatch and the Russian Doll are based on the idea that our Universe may be composed of software running on some kind of cosmic quantum computer, and both feature a computer game developer operating under a tight deadline for a new computer game. While Bandersnatch takes place in 1984 and the Russian Doll series takes place in the present day, both convey the time-pressures that developers experience while working on new code under a tight deadline, but with a twist. In both features, the computer game developers slowly come to the realization that they are caught in some kind of "bad" cosmic code themselves that keeps looping in time. In fact, the line "Life is Like a Box of Timelines" comes from the Russian Doll. Both developers then try to debug and fix the bad cosmic code that they are stuck in. As with all code, debugging and fixing bad cosmic code can be very frustrating and time-consuming. It takes many runs of the bad code with trial code fixes to unit test the cosmic code until it finally performs as intended - see How Software Evolves for more on that.

Fortunately, for the last few decades, we have had IDEs (Integrated Development Environments) like Eclipse that allow developers to step through bad code and watch the variables change with time and also to follow the code logic to see how the code branches at various conditional branch-points. In an IDE, you can also set breakpoints at various points in the code that allow the code to run until the breakpoint is reached. When a breakpoint is reached, the code then stops executing and the developer can then examine the state of all the current code variables. At a breakpoint, the developer can even change the value of a variable on the fly in order to run the code down a different logical path at a conditional branch-point than the code would normally run. Bandersnatch allows the viewer to do this very same thing. At certain points in Bandersnatch, a breakpoint is reached and the viewer then gets to choose which path the cosmic code takes. This allows the viewer to interactively run through the Bandersnatch cosmic code nearly an infinite number of different ways. However, sometimes the viewer will run down a dead-end code path that causes the cosmic code to complete and the credits then begin to roll. At that point, you have to rerun the Bandersnatch cosmic code from the very beginning again. Here is a tip. The Bandersnatch cosmic code also seems to run in the background as a daemon process when you stop debugging the code and come back several hours later. So do not be surprised when you come back and start up Bandersnatch again and find yourself in a different section of the cosmic code than you previously left. All developers should be quite familiar with all of these debugging activities and, therefore, should find debugging cosmic code to be fairly straightforward. Now, in Digital Physics and the Software Universe, we saw that some very bright people hold the position that the best model for explaining the very strange way that our Universe behaves at the microscopic level of atoms and particles is to think of the Universe as some kind of cosmic code running in a quantum-mechanical IDE. But for that, you need some understanding of quantum mechanics. For a brief introduction to quantum mechanics see Quantum Software.

The reason why you will find quantum mechanics useful is that both Bandersnatch and the Russian Doll are based on the idea that our Universe may be composed of software running on some kind of network of cosmic quantum computers, and therefore, also bring in some of the more mind-bending ideas to be found in some of the more esoteric interpretations of quantum mechanics. It should be noted that the more esoteric interpretations of quantum mechanics are also now more important because the classic Copenhagen Interpretation of quantum mechanics no longer seems to carry the weight that it once did many long decades ago. For example, in Quantum Computing and the Many-Worlds Interpretation of Quantum Mechanics we covered Hugh Everett's Many-Worlds Interpretation of quantum mechanics and in Is the Universe a Quantum Computer? we covered John Cramer's Transactional Interpretation of quantum mechanics. Reading both of those postings in advance would help to clarify some of the strange scenes found in both of my Netflix recommendations. For example, in order to explain the strange quantum-mechanical effects that we observe in the lab, the Many-Worlds Interpretation of quantum mechanics relies on timelines in multiple parallel Universes, while the Transactional Interpretation of quantum mechanics relies on a Universe that features multiple timelines moving both forwards and backwards in time at the same time. And both Bandersnatch and the Russian Doll have scenes that display such phenomena. Now to make it a bit easier to understand such phenomena, let us briefly review the Copenhagen Interpretation, the Many-Worlds Interpretation, the Transactional Interpretation and the Decoherence Interpretation of quantum mechanics. But in order to do that we need to know a bit about quantum mechanics and how physicists use the wave model to explain certain phenomena.

The Wave Model
The chief characteristic of the wave model is that waves tend to be everywhere, but nowhere in particular, at the same time and simultaneously explore all possible paths. To see a wave in action, drop a small pebble into a still pond of water containing many obstacles and watch the resulting waves spread out and reflect off the obstacles and interfere with each other before eventually reaching a particular destination near the edge of the pond.

In 1801, Thomas Young conducted a series of experiments with waves. First, using water waves in a shallow ripple tank, he demonstrated the concept of interference. When a water wave encounters a barrier with two slits, the ripples passing through the slits interfere with each other on the other side of the barrier (Figure 1). Where two crests intersect, the wave amplitude doubles in height, and where a crest meets a trough, the two waves cancel each other out entirely. Next, Young used a distant light source with two closely spaced slits in an opaque barrier. On the other side of the barrier, he placed a white projection screen. When light from the distant light source passed through the double-slit barrier, Young observed an interference pattern of alternating bright and dark fringes projected onto the screen which demonstrated the wavelike behavior of light.

Figure 1 – The interference pattern from two slits (click to enlarge)

You can easily repeat Young’s experiment with a piece of thin cloth. At night, hold up a single ply of a pillowcase in front of a distant light source, such as a far-off street light or the filament in your neighbor’s decorative front door light that uses a clear light bulb. Instead of a single diffuse spot of light shining through the pillowcase, you will see a pronounced checkerboard interference pattern of spots, because the weave of your pillowcase has both vertical and horizontal slits between the threads.

The Birth of Modern Quantum Mechanics
As we saw in Quantum Software, Erwin Schrödinger first developed the Schrödinger equation in the winter of 1926 to explain the strange behavior of electrons in atoms and the fact that the electrons only radiated light at certain frequencies when excited. The 1-dimensional version of this famous equation is:

-ħ²    ∂²Ψ  =  iħ ∂Ψ
──      ──            ──
2m    ∂x²            ∂t

In the above 1-dimensional Schrödinger equation, Ψ is called the wavefunction of a particle and is pronounced like the word “sigh”. In quantum mechanics, the wavefunction Ψ contains all of the information that can ever be known about the particle.

Now if the particle is just quietly sitting around on its own and not interacting with other particles, like an electron that has been sitting quietly in an atom for a billion years, it means the wavefunction Ψ should not be changing with time, and we can use the 1-dimensional time-independent version of the Schrödinger equation that does not have the time variable "t" in the equation:

-ħ²  d²ψ(x)   +   V(x) ψ(x)  =  E ψ(x)
──  ──────
2m     dx²

The lower-case wavefunction ψ is still pronounced like the word "sigh", but we use the lower-case ψ to signify that this is a time-independent wavefunction that does not change with time. When the 3-dimensional Schrödinger equation is solved for the hydrogen atom consisting of just one electron trapped by one proton in an electromagnetic well we get a number of quantized wavefunctions as solutions:

Figure 2 – The n=1 and n=2 orbitals or wavefunctions for the hydrogen atom.

The Strange Motion of Quantum Particles in Space and Time
Now for quantum particles like electrons or photons that are on the move we need to use Richard Feynman’s "sum over histories" approach to quantum mechanics. In Feynman's "sum over histories" approach to quantum mechanics, the wavefunction amplitude of an electron or photon is the same in all directions, like when you drop a pebble in a still pond, but the phase angles of the wavefunction will differ depending upon the path that is taken. So to figure out the probability of finding an electron or photon at a particular point, you have to add up the amplitudes and phases of all the possible paths that the electron or photon could have taken to reach the destination point. Although there are an infinite number of possible paths, the key insight is that most of the paths will be out of phase with each other and will cancel out like the destructive interference shown in Figure 1. This produces some rather strange experimental observations. Imagine a very dim source of photons or electrons that can fire one photon or electron at a time. If we fired the particles at a screen with two slits, as in Young’s experiment, we would expect to see a pattern similar to Figure 3 build up over time, based upon the particle model for electrons and photons.

Figure 3 – What common sense and the particle model would predict for a source that fires electrons or photons one at a time

However, what is actually observed is an interference pattern similar to Figure 4, even though the electrons or photons pass through the slits one at a time. According to quantum mechanics, the individual electrons or photons interfere with themselves as they go through both slits at the same time! This means that if your neighbor could turn down the light by his front door to a very low level, so that it only emitted one photon at a time, and your eye could record a long exposure image, you would still see a checkerboard pattern of light spots through your pillowcase, even though the photons went through the fabric mesh one at a time.

Figure 4 – We actually observe an interference pattern as each particle interferes with itself

Now here comes the really strange part. If we put detectors just in front of the slits so that we can record which slit the electron or photon actually passed through, and keep firing one particle at a time, the interference pattern will disappear, and we will see the pattern in Figure 3 instead. If we turn the detectors off, the interference pattern returns, and we see the pattern in Figure 4. For some reason, Nature will not allow us to observe electrons or photons behaving like particles and waves at the same time. It’s some kind of information thing again. But it gets worse. If we put the detectors at some distance behind the slits and turn them on, the interference pattern again disappears, but if we turn the detectors off, the interference pattern returns. Now, this is after the electrons or photons have already passed through the slits! How do they know whether to behave like a wave or a particle in advance, before they know if the detectors are on or off? In fact, experiments have been performed where the decision to turn the detectors on or off is not made until after the individual electrons or photons have already passed through the slits, but even so, if the detectors are turned on, the interference pattern disappears, and if the detectors are turned off, the interference pattern returns! This means that the present can change the past! This is the famous delayed-choice experiment proposed by John Wheeler in 1978 and actually performed by Alain Aspect and his colleagues in 1982. In another experiment, the detectors are placed beyond the observation screen to detect cloned photons that are created in a splitting process. By observing the cloned photons, it is possible to determine which slit an individual twin photon passed through after its twin has already hit the observation screen. When these distant detectors are turned on, the interference pattern once again disappears, and if the detectors are turned off, the interference pattern returns. Again, the decision to turn the detectors on or off can be made after the photons have already hit the observation screen. This means that the future can change the present!

In 1928, Paul Dirac combined quantum mechanics (1926) with the special theory of relativity (1905) and came up with a relativistic reformulation of the Schrödinger equation. Now, strangely, the solutions to Dirac’s equation predicted both the existence of electrons with a negative charge and positive mass energy and also positrons, the antimatter equivalent of electrons, with a positive charge and a negative mass energy. But in 1947 Richard Feynman came up with an alternate interpretation for Dirac’s positrons with negative mass energy. Feynman proposed that positrons were actually normal electrons moving backwards in time! Recall that the full-blown wave function of an object with constant energy can be expressed as a time-independent wavefunction ψ(x) multiplied by a time-varying term:

Ψ(x, t)  =  e^-iEt/ħ  ψ(x)

Now the solutions to Dirac’s equation predicted both the existence of electrons with positive mass energy and also positrons, the antimatter equivalent of electrons, with negative mass energy. For a particle with negative mass energy, the above equation looks like:

Ψ(x, t)  =  e^-i(-E)t/ħ  ψ(x)

but since:

-i(-E)t/ħ = -iE(-t)/ħ

Feynman realized that an equivalent equation could be written by simply changing the parenthesis yielding:

Ψ(x, t)  =  e^-iE(-t)/ħ  ψ(x)

So a positron with negative mass energy –E could mathematically be thought of as a regular old electron with positive mass energy E moving backwards in time! Indeed, today that is the preferred interpretation. All antimatter is simply regular matter moving backwards in time.

Figure 5 – Above is a Feynman diagram showing an electron colliding with a positron, the antimatter version of an electron.

In Figure 5 we see an electron colliding with a positron, the antimatter version of an electron. When the two particles meet they annihilate each other and turn into two γ gamma rays. In the Feynman diagram, space runs along the horizontal axis and time runs along the vertical axis. In the diagram, we see an electron e^- with negative charge and positive mass energy on the left and a positron e⁺ with positive charge and negative mass energy on the right. As time progresses up the vertical time axis, we see the electron e^- and the positron e⁺ approach each other along the horizontal space axis. When the two particles get very close, they annihilate each other and we see two γ gamma rays departing the collision as time proceeds along the vertical time axis. But notice the red arrowheads on the red arrow lines in the Feynman diagram. The red arrowhead for the negative electron e^- is moving upwards on the diagram and forward in time, while the positive positron e⁺ is moving downwards on the diagram and backwards in time! So in the diagram, the positive positron e⁺ is portrayed as an ordinary negative electron e^- moving backwards in time!

The Copenhagen Interpretation of Quantum Mechanics
In 1927, Niels Bohr and Werner Heisenberg proposed a very positivistic interpretation of quantum mechanics now known as the Copenhagen Interpretation. You see, Bohr was working at the University of Copenhagen Institute of Theoretical Physics at the time. The Copenhagen Interpretation contends that absolute reality does not really exist. Instead, there are an infinite number of potential realities, defined by the wavefunction ψ of a quantum system, and when we make a measurement of a quantum system, the wavefunction of the quantum system collapses into a single value that we observe, and thus brings the quantum system into reality (see Quantum Software for more on wavefunctions). This satisfied Max Born’s contention that wavefunctions are just probability waves. The Copenhagen Interpretation suffers from several philosophical problems though. For example, Eugene Wigner pointed out that the devices we use to measure quantum events are also made out of atoms which are quantum objects in themselves, so when an observation is made of a single atom of uranium to see if it has gone through a radioactive decay using a Geiger counter, the atomic quantum particles of the Geiger counter become entangled in a quantum superposition of states with the uranium atom. If the uranium has decayed, then the uranium atom and the Geiger counter are in one quantum state, and if the atom has not decayed, then the uranium atom and the Geiger counter are in a different quantum state. If the Geiger counter is fed into an amplifier, then we have to add in the amplifier too into our quantum superposition of states. If a physicist is patiently listening to the Geiger counter, we have to add him into the chain as well, so that he can write and publish a paper which is read by other physicists and is picked up by Time magazine for a popular presentation to the public. So when does the “measurement” actually take place? We seem to have an infinite regress. Wigner’s contention is that the measurement takes place when a conscious being first becomes aware of the observation. Einstein had a hard time with the Copenhagen Interpretation of quantum mechanics for this very reason because he thought that it verged upon solipsism. Solipsism is a philosophical idea from Ancient Greece. In solipsism, your Mind is the whole thing, and the physical Universe is just a figment of your imagination. So I would like to thank you very much for thinking of me and bringing me into existence! Einstein’s opinion of the Copenhagen Interpretation of quantum mechanics can best be summed up by his statement "Is it enough that a mouse observes that the Moon exists?". Einstein objected to the requirement for a conscious being to bring the Universe into existence because, in Einstein’s view, measurements simply revealed to us the condition of an already existing reality that does not need us around to make measurements in order to exist. But in the Copenhagen Interpretation, the absolute reality of Einstein does not really exist. Additionally, in the Copenhagen Interpretation, objects do not really exist until a measurement is taken, which collapses their associated wavefunctions, but the mathematics of quantum mechanics does not shed any light on how a measurement could collapse a wavefunction.

The collapse of the wavefunction is also a one-way street. According to the mathematics of quantum mechanics a wavefunction changes with time in a deterministic manner, so like all of the other current effective theories of physics, they are reversible in time and can be run backwards. This is also true in the Copenhagen Interpretation, so long as you do not observe the wavefunction and collapse it by the process of observing it. In the Copenhagen Interpretation, once you observe a wavefunction and collapse it, you cannot undo the collapse, so the process of observation becomes nonreversible in time. That means if you fire photons at a target, but do not observe them, it is possible to reverse them all in time and return the Universe back to its original state. That is how all of the other effective theories of physics currently operate. But in the Copenhagen Interpretation, if you do observe the outgoing photons you can never return the Universe back to its original state. This can best be summed up by the old quantum mechanical adage - look particle, don’t look wave. A good way to image this in your mind is to think of a circular tub of water. If you drop a pebble into the exact center of a circular tub of water, a series of circular waves will propagate out from the center. Think of those waves as the wavefunction of an electron changing with time into the future according to the Schrödinger equation. When the circular waves hit the circular walls of the tub they will be reflected back to the center of the tub. Essentially, they can be viewed as moving backwards in time. This can happen in the Copenhagen Interpretation so long as the electron is never observed as its wavefunction moves forward or backward in time. However, if the wavefunction is observed and collapsed, it can never move backwards in time, so observation becomes a one-way street.

The Many-Worlds Interpretation of Quantum Mechanics
In 1956, Hugh Everett working on his Ph.D. under John Wheeler, proposed the Many-Worlds Interpretation of quantum mechanics as an alternative. The Many-Worlds Interpretation admits to an absolute reality but claims that there are an infinite number of absolute realities spread across an infinite number of parallel universes. In the Many-Worlds Interpretation, when electrons or photons encounter a two-slit experiment, they go through one slit or the other, and when they hit the projection screen they interfere with electrons or photons from other universes that went through the other slit! In Everett’s original version of the Many-Worlds Interpretation, the entire Universe splits into two distinct universes whenever a particle is faced with a choice of quantum states, and so all of these universes are constantly branching into an ever-growing number of additional universes. In the Many-Worlds Interpretation of quantum mechanics, the wavefunctions or probability clouds of electrons surrounding an atomic nucleus are the result of overlaying the images of many “real” electrons in many parallel universes. Thus, according to the Many-Worlds Interpretation wavefunctions never collapse. They just deterministically evolve in an abstract mathematical Hilbert space and are reversible in time, like everything else in physics.

Because Einstein detested the Copenhagen interpretation of quantum mechanics so much, he published a paper in 1935 with Boris Podolsky and Nathan Rosen which outlined what is now known as the EPR Paradox. But to understand the EPR Paradox we need a little background in experimental physics. Electrons have a quantum mechanical property called spin. You can think of an electron’s spin like the electron has a little built-in magnet. In fact, it is the spin of the little electron magnets that add up to make the real magnets that you put on your refrigerator. Now in quantum mechanics, the spin of a single electron can be both up and down at the same time because the single electron can be in a mixture of quantum states! But in the classical Universe that we are used to, macroscopic things like a child's top can only have a spin of up or down at any given time. The top can only spin in a clockwise or counterclockwise manner at one time - it cannot do both at the same time. Similarly, in quantum mechanics, a photon or electron can go through both slits of a double slit experiment at the same time, so long as you do not put detectors at the slit locations.

Figure 6 – A macroscopic top can only spin clockwise or counterclockwise at one time.

Figure 7 – But electrons can be in a mixed quantum mechanical state in which they both spin up and spin down at the same time.

Figure 8 – Similarly, tennis balls can only go through one slit in a fence at a time. They cannot go through both slits of a fence at the same time.

Figure 9 – But at the smallest of scales in our quantum mechanical Universe, electrons and photons can go through both slits at the same time, producing an interference pattern.

Figure 10 – You can see this interference pattern of photons if you look at a distant porch light through the mesh of a sheer window curtain or a pillowcase.

When you throw an electron through a distorted magnetic field that is pointing up the electron will pop out in one of two states. It will either be aligned with the magnetic field (called spin-up) or it will be pointing 180^o in the opposite direction of the magnetic field (called spin-down). Both the spin-up and spin-down conditions are called an eigenstate. Prior to the observation of the electron’s spin, the electron is in a superposition of states and is not in an eigenstate. Now if the electron in the eigenstate of spin-up is sent through the same magnetic field again, it will be found to pop out in the eigenstate of spin-up again. Similarly, a spin-down electron that is sent through the magnetic field again will also pop out as a spin-down electron. Now here is the strange part. If you rotate the magnetic field by 90^o and send spin-up electrons through it, 50% of the electrons will pop out with a spin pointing to the left, and 50% will pop out with a spin pointing to the right. And you cannot predict in advance which way a particular spin-up electron will pop out. It might spin to the left, or it might spin to the right. The same goes for the spin-down electrons – 50% will pop out spinning to the left and 50% will pop out spinning to the right.

Figure 11 - In the Stern-Gerlach experiment we shoot electrons through a distorted magnetic field. Classically, we would expect the electrons to be spinning in random directions and the magnetic field should deflect them in random directions, creating a smeared out spot on the screen. Instead, we see that the act of measuring the spins of the electrons puts them into eigenstates with eigenvalues of spin-up or spin-down and the electrons are either deflected up or down. If we rotate the magnets by 90^o, we find that the electrons are deflected to the right or to the left.

The EPR Paradox goes like this. Suppose we prepare many pairs of quantum mechanically “entangled” electrons that conserve angular momentum. Each pair consists of one spin-up electron and one spin-down electron, but we do not know which is which at the onset. Now let the pairs of electrons fly apart and let two observers measure their spins. If observer A measures an electron there will be a 50% probability that he will find a spin-up electron and a 50% chance that he will find a spin-down electron, and the same goes for observer B, 50% of observer’s B electrons will be found to have a spin-up, while 50% will be found with a spin-down. Now the paradox of the EPR paradox, from the perspective of the Copenhagen Interpretation, is that when observer A and observer B come together to compare notes, they find that each time observer A found a spin-up electron, observer B found a spin-down electron, even though the electrons did not know which way they were spinning before the measurements were performed. Somehow when observer A measured the spin of an electron, it instantaneously changed the spin of the electron that observer B measured. Einstein hated this “spooky action at a distance” feature of the Copenhagen Interpretation that made physics nonlocal, meaning that things that were separated by great distances could still instantaneously change each other. He thought that it violated the speed of light speed limit of his special theory of relativity that did not allow information to travel faster than the speed of light. Einstein thought that the EPR paradox was the final nail in the coffin of quantum mechanics. There had to be some “hidden variables” that allowed electrons to know if they “really” were a spin-up or spin-down electron. You see, for Einstein, absolute reality really existed. For Einstein, the apparent probabilistic nature of quantum mechanics was an illusion, like the random() function found in most computer languages. The random() function just points to a table of apparently random numbers that are totally predictable if you look at the table in advance. You normally initiate the random() function with a “seed” from the system clock of the computer you are running on to simulate randomness by starting at different points in the table.

However, in 1964 John S. Bell published a paper in which he proposed an experiment that could actually test the EPR Paradox. In the 1980s and 1990s, a series of experiments were indeed performed that showed that Einstein was actually wrong. Using photons and polarimeters, instead of the spin of electrons, these experiments showed that photons really do not know their quantum states in advance of being measured and that determining the polarization of a photon by observer A can immediately change the polarization of another photon 60 miles away. These experiments demonstrated that the physical Universe is non-local, meaning that Newton’s spooky “action at a distance” is built into our Universe, at least for entangled quantum particles. This might sound like a violation of the special theory of relativity because it seems like we are sending an instantaneous message faster than the speed of light, but that is really not the case. Both observer A and observer B will measure photons with varying polarizations at their observing stations separated by 60 miles. Only when observer A and observer B come together to compare results will they realize that their observations were correlated, so it is impossible to send a message with real information using this experimental scheme. Clearly, our common-sense ideas about space and time are still lacking, and so are our current effective theories.

Hugh Everett solves this problem by letting the electrons be in all possible spin states in a large number of parallel universes. When observers measure the spin of an electron, they really do not measure the spin of the electron. They really measure in which universe they happen to be located in, and since everything in the Many-Worlds Interpretation relies on “correlated” composite wavefunctions, it should come as no surprise that when observer A and observer B come together, they find that their measurements of the electron spins are correlated. In the Many-Worlds Interpretation, Hugh Everett proposes that when a device, like our magnets above, measures the spin of an electron that is in an unknown state, and not in a spin-up or spin-down eigenstate, the device does not put the electron into a spin-up or spin-down eigenstate as the Copenhagen Interpretation maintains. Instead, the device and the electron enter into a correlated composite system state or combined wavefunction with an indeterminate spin of the electron. Hugh Everett explains how this new worldview can be used to explain what we observe in the lab. In fact, he proposes that from the perspective of the measuring magnets and the electron, two independent observational histories will emerge, one with the measuring magnets finding a spin-up electron and one with the measuring magnets finding a spin-down electron, and both of these will be just as “real” as the other. For them, the Universe has essentially split in two, with each set in its own Universe. That is where the “Many-Worlds” in the Many-Worlds Interpretation of quantum mechanics comes from.

While doing research for The Software Universe as an Implementation of the Mathematical Universe Hypothesis I naturally consulted Max Tegmark’s HomePage at:

http://space.mit.edu/home/tegmark/mathematical.html

and I found a link there to Hugh Everett’s original 137-page Jan 1956 draft Ph.D. thesis in which he laid down the foundations for the Many-Worlds Interpretation. This is a rare document indeed because on March 1, 1957, Everett submitted a very compressed version of his theory in his final 36-page doctoral dissertation, "On the Foundations of Quantum Mechanics", after heavy editing by his thesis advisor John Wheeler to make his Ph.D. thesis more palatable to the committee that would be hearing his oral defense and also to not offend Niels Bohr, one of the founding fathers of the Copenhagen Interpretation and still one of its most prominent proponents. But years later John Wheeler really did want to know what Niels Bohr thought of Hugh Everett’s new theory and encouraged Everett to visit Copenhagen in order to meet with Bohr. Everett and his wife did finally travel to Copenhagen in March of 1959 and spent six weeks there. But by all accounts, the meeting between Bohr and Everett was a disaster, with Bohr not even discussing the Many-Worlds Interpretation with Everett.

Below is the link to Hugh Everett’s original 137-page Jan 1956 draft Ph.D. thesis:

http://www.pbs.org/wgbh/nova/manyworlds/pdf/dissertation.pdf

I have also placed his thesis on Microsoft One Drive at:

https://onedrive.live.com/redir?resid=21488ff1cf19c88b!1437&authkey=!ADIm_WTYLkbx90I&ithint=file%2cpdf

in Quantum Computing and the Many-Worlds Interpretation of Quantum Mechanics, I step through the above document page-by-page and offer up a translation of the mathematics into easily understood terms.

The Transactional Interpretation of Quantum Mechanics
In Is the Universe a Quantum Computer? I covered John Cramer's Transactional Interpretation of quantum mechanics and compared it to TCP/IP transactions on the Internet. In an email exchange with John Cramer, I learned that such a comparison had never been done before. Now in the Copenhagen interpretation of quantum mechanics, the wavefunctions Ψ of particles and photons are not “real” waves, they are only probability waves – just convenient mathematical constructs that don’t “really” exist. But in Cramer’s Transactional Interpretation of quantum mechanics, the wavefunctions Ψ of particles and photons really do exist. For a physics student new to quantum mechanics, this is truly a comforting idea. Before they teach you about quantum mechanics, you go through a lengthy development of wave theory in courses on classical electrodynamics, optics, and differential equations. In all these courses, you only deal with waves that are mathematically real, meaning that these waves have no imaginary parts using the imaginary number i where i² = -1. But in your first course on quantum mechanics, you are introduced to Schrödinger’s equation:

-ħ²    ∂²Ψ  =  iħ ∂Ψ
──      ──            ──
2m    ∂x²            ∂t

and learn that generally, the wavefunction solutions to Schrödinger’s equation contain both real and imaginary parts containing the nasty imaginary number i. Consequently, the conventional wisdom is that the wavefunction solutions to Schrödinger’s equation cannot really exist as real tangible things. They must just be some kind of useful mathematical construct. However, in the same course, you are also taught about Davisson and Germer bouncing electrons off the lattice of a nickel crystal and observing an interference pattern, so something must be waving! I would venture to suggest that nearly all students new to quantum mechanics initially think of wavefunctions as real waves waving in space. Only with great coaxing by their professors do these students “unlearn” this idea with considerable reluctance.

As we saw previously, the imaginary parts of wavefunctions really bothered the founding fathers of quantum mechanics too. Recall that in 1928, Max Born came up with the clever trick of multiplying the wavefunctions Ψ by their complex conjugates Ψ* to get rid of the imaginary parts. To create the complex conjugate of a complex number or function, all you have to do is replace the imaginary number i with –i wherever you see it. According to Born’s conjecture, the probability of things happening in the quantum world are proportional to multiplying the wavefunction by its complex conjugate Ψ*Ψ. Mathematically, this is the same thing as finding the square of the amplitude of the wavefunction. Now earlier in this posting, I mentioned how Richard Feynman pointed out that instead of thinking of positrons having negative mass energy, you could also think of positrons as regular electrons with negative charge moving backwards in time by shifting the position of the “-“ sign in the wavefunction of a positron. But that is just the same thing as using the complex conjugate Ψ* of an electron wavefunction for a positron. So mathematically, we can think of the complex wavefunction of a particle Ψ* as the wavefunction of the particle moving backwards in time. Cramer suggests that Born’s idea of Ψ*Ψ representing the probability of a quantum event is not just a mathematical trick or construct, rather it is the collision of an outgoing “retarded” wave Ψ moving forwards in time with an incoming Ψ* “advanced” wave moving backwards in time. Essentially, John Cramer's Transactional Interpretation of quantum mechanics sees the collision of outgoing “retarded” waves Ψ moving forwards in time with incoming Ψ* “advanced” waves moving backwards in time.

The Transactional Interpretation easily explains all of the apparent paradoxes of quantum mechanics. As we have seen, there is actual experimental evidence that electrons and photons seem to “know” in advance what they will encounter on the other side of a double-slit experiment. This is easily explained by the Transactional Interpretation. The electrons or photons send out retarded waves into the future which interact with whatever lies beyond the slits. If there are detectors that are turned on, the retarded waves interact with them, if there are no detectors, the waves interact with some electrons on a projection screen instead. In either case, an advanced wave is sent backwards in time from the detectors or the projection screen to the point of origin of the electrons or photons so that they “know” how to behave before they get to the two-slit screen.

The Decoherence Interpretation
Quantum decoherence is another popular interpretation of quantum mechanics. In quantum decoherence, there are again a large number of parallel possibilities for the wavefunctions for things like electrons, but many closely related wavefunctions interact with each other and become quantum-mechanically “entangled” with each other in a quantum superposition of states, forming a Universe of their own. This interpretation of quantum mechanics seems to be very popular amongst the quantum mechanical engineers working on quantum computers because they are always fighting with decoherence. Quantum computers are very delicate machines. If you try to measure the output before the run completes, the whole thing will abend. The problem is that the results of a computation are not in our universe alone; we can only obtain a solution to a computation by looking at the interference of the various results in all the parallel universes together. If we try to take a peek before all these parallel runs complete, the whole system of qubits will decohere because we have taken a measurement of the system, and our quantum calculation will crash.

Conclusion
I hope that some of the above quantum-mechanical craziness that we observe in our Universe helps with watching both of the Netflix features Bandersnatch and the Russian Doll. I would also like to thank Netflix for producing these fine quantum-mechanical productions that can help the general public to become more familiar with the phenomena of quantum mechanics and with the potentials of quantum computer software.

Comments are welcome at scj333@sbcglobal.net

To see all posts on softwarephysics in reverse order go to:
https://softwarephysics.blogspot.com/

Regards,
Steve Johnston

Digital Physics and the Software Universe

I just watched a very interesting panel discussion from an old World Science Festival meeting that was held on Saturday, June 4, 2011, 8:00 PM - 9:30 PM:

Rebooting the Cosmos: Is the Universe the Ultimate Computer?
https://www.worldsciencefestival.com/videos/rebooting-the-cosmos-is-the-universe-the-ultimate-computer/

The panel discussion was moderated by John Hockenberry and featured Edward Fredkin, Seth Lloyd, Jürgen Schmidhuber and Fotini Markopoulou-Kalamara. The World Science Festival is an annual event hosted by string theorist Brian Greene and is an outgrowth of the World Science U. At the World Science U, you can view many very interesting lectures and courses, and at the World Science Festival website you can view many very interesting panel discussions:

World Science U
http://www.worldscienceu.com/

World Science Festival
https://www.worldsciencefestival.com/

Edward Fredkin started working with computers back in 1956. In 1960, he wrote the first OS and the first Assembler program for the DEC PDP-1. Then in 1968, Edward Fredkin returned to academia and became a full professor at MIT. In 1990, Edward Fredkin published the paper Digital Mechanics - An informational process based on reversible universal cellular automata in the ACM, in which he proposed that the physical Universe might be a cellular automaton programmed to act like physics and launched the field of Digital Physics. Since then, Fredkin has broadened the field by renaming it to Digital Philosophy. You can find his Digital Philosophy website at:

Digital Philosophy
http://www.digitalphilosophy.org/

On the Home page, he briefly defines Digital Philosophy as:

"What is Digital Philosophy?
Digital Philosophy (DP) is a new way of thinking about the fundamental workings of processes in nature. DP is an atomic theory carried to a logical extreme where all quantities in nature are finite and discrete. This means that, theoretically, any quantity can be represented exactly by an integer. Further, DP implies that nature harbors no infinities, infinitesimals, continuities, or locally determined random variables. This paper explores Digital Philosophy by examining the consequences of these premises.

At the most fundamental levels of physics, DP implies a totally discrete process called Digital Mechanics. Digital Mechanics[1] (DM) must be a substrate for Quantum Mechanics. Digital Philosophy makes sense with regard to any system if the following assumptions are true:

All the fundamental quantities that represent the state information of the system are ultimately discrete. In principle, an integer can always be an exact representation of every such quantity. For example, there is always an integral number of neutrons in a particular atom. Therefore, configurations of bits, like the binary digits in a computer, can correspond exactly to the most microscopic representation of that kind of state information.

In principle, the temporal evolution of the state information (numbers and kinds of particles) of such a system can be exactly modeled by a digital informational process similar to what goes on in a computer. Such models are straightforward in the case where we are keeping track only of the numbers and kinds of particles. For example, if an oracle announces that a neutron decayed into a proton, an electron, and a neutrino, it’s easy to see how a computer could exactly keep track of the changes to the numbers and kinds of particles in the system. Subtract 1 from the number of neutrons, and add 1 to each of the numbers of protons, electrons, and neutrinos.

The possibility that DP may apply to various fields of science motivates this study."

While you are on his website, be sure to check out some of Edward Fredkin's publications at:

http://www.digitalphilosophy.org/index.php/essays/

In 2002, Seth Lloyd at MIT published The Computational Universe, in which he calculated the computing power of the entire physical Universe treated as one large quantum computer. You can read this fascinating paper at:

http://www.edge.org/3rd_culture/lloyd2/lloyd2_p2.html

Seth Lloyd is currently working on quantum computers at MIT and is the first quantum-mechanical engineer in MIT’s Mechanical Engineering department. Seth Lloyd is recognized for proposing the first technologically feasible design for a quantum computer. In 2006 he published the book Programming the Universe: A Quantum Computer Scientist Takes on the Cosmos in which he contends that our Universe is a quantum mechanical Computational Universe that has been calculating how to behave from the very beginning. He came to this conclusion as MIT’s sole quantum mechanical engineer working on building practical quantum computers. During the course of his research, Seth Lloyd has learned how to talk to atoms in a quantum mechanical way. Through intimate dealings with atoms, he has found that atoms are constantly flipping quantum mechanical states in a controlled manner prescribed by quantum mechanics. Since a computer is simply a large number of switches that operate in a controlled manner, our Universe can, therefore, be thought of as a Computational Universe, and therefore, must necessarily be capable of computation. In fact, our current quest to build quantum computers can simply be viewed as an attempt to domesticate this natural tendency for our Universe to compute in a quantum mechanical manner. Seth Lloyd calculates that our section of the Computational Universe which is defined by our current cosmic horizon and consists of all quantum particles out to a distance of 46 billion light years, has performed about 10¹²² operations on 10⁹² bits over the past 13.8 billion years. This domestication of the quantum mechanical behavior of our Computational Universe has already led to the construction of many trillions of classical computers already.

Since Seth Lloyd proposes that our Universe is simply a vast quantum computer calculating how to perform, perhaps in 1,000 years when software has finally become the dominant form of self-replicating information on the planet and is running on huge networks of quantum computers, it will make no distinction between the “real” Universe and the “simulated” universes that it can easily cook up on its own hardware. Perhaps as we saw in Quantum Computing and the Many-Worlds Interpretation of Quantum Mechanics the software running on these vast networks of quantum computers of the future will come to realize that the Many-Worlds interpretation of quantum mechanics is indeed correct, and that the humans of long ago were simply a large collection of quantum particles constantly getting entangled or “correlated” with other quantum particles, and splitting off into parallel universes in the process. This constant splitting gave the long-forgotten humans the delusion that they were conscious beings with free will and led them to do very strange things, like look for similarly deluded entities.

Jürgen Schmidhuber is a renowned AI researcher and currently the Scientific Director of the Swiss AI Lab IDSIA (Istituto Dalle Molle di Studi sull'Intelligenza Artificiale). His Home Page has many interesting links:

Jürgen Schmidhuber's Home Page
http://people.idsia.ch/~juergen/

Fotini Markopoulou-Kalamara is one of the founding faculty members of the Perimeter Institute for Theoretical Physics and works on loop quantum gravity. Loop quantum gravity is a theory that tries to bridge the gap between Einstein's general relativity and quantum mechanics to produce a quantum theory of gravity. Nearly all of the current theories of physics are background-dependent theories that unfold upon a stage of pre-existing spacetime. For example, the Standard Model of particle physics and string theory both assume that there is a stage of pre-existing spacetime upon which they act to produce what we observe in our Universe. Loop quantum gravity does not have such a stage and is therefore background-independent. In loop quantum gravity, spacetime is quantized into a network of nodes called a spin network. The minimum distance between nodes is about one Planck length of about 10^-35 meters. Loop quantum gravity is a background-independent theory because the spin network can be an emergent property of the Universe that evolves with time. Similarly, Digital Physics is a background-independent theory because spacetime emerges as a quantized entity and is not a stage upon which physics acts.

Nick Bostrom’s Are You Living in a Computer Simulation? (2002) at:

http://www.simulation-argument.com/simulation.html

is also a good reference on this topic.

Rebooting the Cosmos: Is the Universe the Ultimate Computer? examines the idea that the physical Universe may essentially be running on a large network of quantum computers. The most interesting thing about this panel discussion was that midway through it, the participants brought up the initial work of Konrad Zuse on this topic. Recall that Konrad Zuse started working on building real computers back in 1936, the same year that Alan Turing of early computer science fame published the mathematical concept of the Turing Machine in On Computable Numbers, with an Application to the Entscheidungsproblem that today underlies the architecture for all modern computers. Alan Turing’s work was completely conceptual in nature, and in the paper, he proposed the theoretical concept of a Turing Machine. A Turing Machine was composed of a read/write head and an infinitely long paper tape. On the paper tape, was stored a sequential series of 1s and 0s, and the read/write head could move back and forth along the paper tape in a motion based upon the 1s and 0s that it read. The read/write head could also write 1s and 0s to the paper tape as well. In Turing’s paper, he mathematically proved that such an arrangement could be used to encode any mathematical algorithm, like multiplying two very large numbers together and storing the result on the paper tape. In many ways, a Turing Machine is much like a ribosome reading mRNA and writing out the amino acids of a polypeptide chain that eventually fold up into an operational protein.

Figure 1 - A Turing Machine had a read/write head and an infinitely long paper tape. The read/write head could read instructions on the tape that were encoded as a sequence of 1s and 0s and could write out the results of following the instructions on the paper tape back to the tape as a sequence of 1s and 0s.

Figure 2 – A ribosome read/write head behaves much like the read/write head of a Turing Machine. The ribosome reads an mRNA tape that was transcribed earlier from a section of DNA tape that encodes the information in a gene. The ribosome read/write head then reads the A, C, G, and U nucleobases that code for amino acids three at a time. As each 3-bit byte is read on the mRNA tape, the ribosome writes out an amino acid to a growing polypeptide chain, as tRNA units bring in one amino acid at a time. The polypeptide chain then goes on to fold up into a 3-D protein molecule.

In a sense, all modern computers are loosely based upon the concept of a Turing Machine. Turing did not realize it, but at the same time he was formulating the concept of a Turing Machine back in 1936, Konrad Zuse was constructing his totally mechanical Z1 computer in the living room of his parent’s apartment in Germany, and the Z1 really did use a paper tape to store the program and data that it processed, much like a Turing Machine. Neither one of these early computer pioneers had any knowledge of the other at the time. For more about how Konrad Zuse independently developed a physical implementation of many of Alan Turing’s mathematical concepts, but also implemented them in practical terms in the form of the world’s very first real computers, see the following article that was written in his own words:

http://ei.cs.vt.edu/~history/Zuse.html

Figure 3 - A reconstructed mechanical Z1 computer completed by Konrad Zuse in 1989. The original Z1 was constructed 1936 - 1938 in the living room of his parent’s apartment in Germany. The Z1 was not a full-fledged modern computer, like Zuse’s Z3 computer that became operational in May of 1941 because it read programs from a punched tape that were not stored in the mechanical memory of the Z1. In that regard, the Z1 was more like a Turing Machine than are modern computers.

Figure 4 – Konrad Zuse with a reconstructed Z3 in 1961.

Figure 5 – Block diagram of the Z3 architecture.

Zuse's totally mechanical Z1 became operational in 1938. Zuse then went on to build his electrical Z3 computer with 2400 electromechanical telephone relays. The Z3 was the world’s very first full-fledged computer and became operational in May of 1941. The Z3 used a 22-bit word and had a total memory of 64 words. It only had two registers, but it could read in and store programs in memory via a punched tape. Because the Z3 used very slow electromechanical telephone relays for switches, the Z3 had a clock speed of 5.33 Hz and it took about 3 seconds to multiply two large numbers together. Modern laptops have a clock speed of 2.5 - 3.5 GHz so they are nearly a billion times faster than the Z3. Electromechanical telephone relays have a switching speed of about 10^-1 seconds while vacuum tubes are about 100,000 times faster with a switching speed of about 10^-6 seconds. However, back in 1941, Zuse thought that building a computer with thousands of vacuum tubes would use too much electricity and would be too unreliable for a practical computer. But in the 1950s we actually did end up building computers with thousands of vacuum tubes.

Figure 6 – The electrical relays used by the Z3 for switching were very large, very slow and used a great deal of electricity that generated a great deal of waste heat.

Figure 7 – In the 1950s, the electrical relays of the Z3 were replaced with vacuum tubes that were also very large, used lots of electricity and generated lots of waste heat too, but the vacuum tubes were 100,000 times faster than relays.

Figure 8 – Vacuum tubes contain a hot negative cathode that glows red and boils off electrons. The electrons are attracted to the cold positive anode plate, but there is a gate electrode between the cathode and anode plate. By changing the voltage on the grid, the vacuum tube can control the flow of electrons like the handle of a faucet. The grid voltage can be adjusted so that the electron flow is full blast, a trickle, or completely shut off, and that is how a vacuum tube can be used as a switch.

When I first changed careers to become an IT professional in 1979, I used to talk to the old-timers about the good old days of IT. They told me that when the operators began their shift on an old-time 1950s vacuum tube computer, the first thing they did was to crank up the voltage on the vacuum tubes to burn out the tubes that were on their last legs. Then they would replace the burned-out tubes to start the day with a fresh machine. So using slow electromechanical telephone relays for the Z3 was really not such a bad idea back in 1941. For example, they also told me about programming the plugboards of electromechanical Unit Record Processing machines back in the 1950s by physically rewiring the plugboards. The Unit Record Processing machines would then process hundreds of punch cards per minute by routing the punch cards from machine to machine in processing streams.

Figure 9 – In the 1950s Unit Record Processing machines like this card sorter were programmed by physicaly rewiring a plugboard.

Figure 10 – The plugboard for a Unit Record Processing machine.

In 1945, while Berlin was being bombed by over 800 bombers each day, Zuse worked on the Z4 and developed Plankalkuel, the first high-level computer language more than 10 years before the appearance of FORTRAN in 1956. Zuse was able to write the world’s first chess program with Plankalkuel. And in 1950 his startup company Zuse-Ingenieurbüro Hopferau began to sell the world’s first commercial computer, the Z4, 10 months before the sale of the first UNIVAC I. However, the Z4 still used the very slow electromechanical relays, while the UNIVAC I primarily used vacuum tubes. The UNIVAC I was 25 feet by 50 feet in size and contained 5,600 vacuum tubes, 18,000 crystal diodes and 300 electromechanical relays with a total memory of 12 K.

Figure 11 – The UNIVAC I was very impressive on the outside.

Figure 12 – But the UNIVAC I was a little less impressive on the inside.

The Z4 just could not stand up to such powerful hardware!

Not only is Konrad Zuse the first person to ever build a modern operational computer, but he is also responsible for the idea of using a network of computers as a model for the behavior of the physical Universe. In 1969, Konrad Zuse published Rechnender Raum which translates into English as Calculating Space. An English translation of this short book can be downloaded at:

https://1drv.ms/b/c/c470796a085fc72b/ESvHXwhqeXAggMRJCAAAAAABatMYtI7fmBPs48RGEsb7JQ?e=t2ysKR

In Rebooting the Cosmos: Is the Universe the Ultimate Computer?, Edward Fredkin explained that he found the original German version of Calculating Space in the MIT library and had it translated into English so that he could read it. After reading Calculating Space, Edward Fredkin contacted Konrad Zuse about his ideas that our Universe was a simulation running on a network of computers. Unfortunately, Konrad Zuse had to explain to Edward Fredkin that after he published Calculating Space, people stopped talking to him because they thought that he was some kind of "crackpot". Even so, later, Edward Fredkin invited Konrad Zuse to MIT to a conference hosted by Richard Feynman, with John Wheeler in attendance, to discuss his ideas. For more on the work of Richard Feynman see Hierarchiology and the Phenomenon of Self-Organizing Organizational Collapse and The Foundations of Quantum Computing.

This conference probably influenced John Wheeler's "it from bit" ideas but my Internet searches cannot confirm that. For example, in 1998 John Wheeler stated, "it is not unreasonable to imagine that information sits at the core of physics, just as it sits at the core of a computer". Building upon his famous ”it from bit” commentary, David Chalmers of the Australian National University has summarized Wheeler’s thoughts as:

"Wheeler (1990) has suggested that information is fundamental to the physics of the universe. According to this "it from bit" doctrine, the laws of physics can be cast in terms of information, postulating different states that give rise to different effects without actually saying what those states are. It is only their position in an information space that counts. If so, then information is a natural candidate to also play a role in a fundamental theory of consciousness. We are led to a conception of the world on which information is truly fundamental, and on which it has two basic aspects, corresponding to the physical and the phenomenal features of the world".

For Jürgen Schmidhuber's thoughts on the work of Konrad Zuse see these pages on his website:

Zuse's Thesis: The Universe is a Computer
http://people.idsia.ch/~juergen/digitalphysics.html

Computable Universes & Algorithmic Theory of Everything: The Computational Multiverse
http://people.idsia.ch/~juergen/computeruniverse.html

Later in life, Konrad Zuse took up art and began painting some very striking modernistic works. If you Google for images of "Konrad Zuse Paintings" you will find quite a few examples. Below is a Zuse painting of his concept of the Universe as a running program.

Figure 13 – Konrad Zuse's In the beginning was the code.

So is the Universe Really Software Running on a Cosmic Computer?
From the above material, we can see that Konrad Zuse, Edward Fredkin, Jürgen Schmidhuber and Nick Bostrom make the case that our Universe is indeed just one of many possible computer simulations running on some kind of cosmic computer. Seth Lloyd, on the other hand, leans more to the idea of the Universe itself being some kind of a quantum computer calculating how to behave. Now with softwarephysics, I have maintained more of a positivistic position. Recall that positivism is an enhanced form of empiricism, in which we do not care about how things “really” are; we are only interested in how things are observed to behave. With positivism, physicists only seek out models of reality - not reality itself. So with softwarephysics, we simply observe that the Universe appears to behave like software running on a cosmic computer and leave it at that. Recall that softwarephysics depicts software as a virtual substance, and relies on our understanding of the current theories in physics, chemistry, biology, and geology to help us model the nature of software behavior. So in physics, we use software to simulate the behavior of the Universe, while in softwarephysics, we use the Universe to simulate the behavior of software. Along these lines, we use the Equivalence Conjecture of Softwarephysics as an aid; it allows us to shift back and forth between the Software Universe and the physical Universe, and hopefully to learn something about one by examining the other:

The Equivalence Conjecture of Softwarephysics
Over the past 78 years, through the uncoordinated efforts of over 50 million independently acting programmers to provide the world with a global supply of software, the IT community has accidentally spent more than $10 trillion creating a computer simulation of the physical Universe on a grand scale – the Software Universe.

The battle between realists and positivists goes all the way back to the beginning. It is generally thought that the modern Scientific Revolution of the 16th century began in 1543 when Nicolaus Copernicus published On the Revolutions of the Heavenly Spheres, in which he proposed his Copernican heliocentric theory that held that the Earth was not the center of the Universe, but that the Sun held that position and that the Earth and the other planets revolved about the Sun. A few years ago I read On the Revolutions of the Heavenly Spheres and found that it began with a very strange foreword that essentially said that the book was not claiming that the Earth actually revolved about the Sun, rather the foreword proposed that astronomers may adopt many different models that explain the observed motions of the Sun, Moon, and planets in the sky, and so long as these models make reliable predictions, they don’t have to exactly match up with the absolute truth. Since the foreword did not anticipate space travel, it also implied that since nobody will ever really know for sure anyway, because nobody will ever be able to see from above what is really going on, there is no need to get too bent out of shape over the idea of the Earth moving. I found this foreword rather puzzling and so disturbing that I almost put On the Revolutions of the Heavenly Spheres down. But a little further research revealed the true story. However, before we get to that, below is the complete foreword to On the Revolutions of the Heavenly Spheres in its entirety. It is well worth reading because it perfectly encapsulates the ongoing philosophical clash between positivism and realism in the history of physics.

"To the Reader
Concerning the Hypotheses of this Work

There have already been widespread reports about the novel hypotheses of this work, which declares that the earth moves whereas the sun is at rest in the center of the universe. Hence certain scholars, I have no doubt, are deeply offended and believe that the liberal arts, which were established long ago on a sound basis, should not be thrown into confusion. But if these men are willing to examine the matter closely, they will find that the author of this work has done nothing blameworthy. For it is the duty of an astronomer to compose the history of the celestial motions through careful and expert study. Then he must conceive and devise the causes of these motions or hypotheses about them. Since he cannot in any way attain to the true causes, he will adopt whatever suppositions enable the motions to be computed correctly from the principles of geometry for the future as well as for the past. The present author has performed both these duties excellently. For these hypotheses need not be true nor even probable. On the contrary, if they provide a calculus consistent with the observations, that alone is enough. Perhaps there is someone who is so ignorant of geometry and optics that he regards the epicycle of Venus as probable, or thinks that it is the reason why Venus sometimes precedes and sometimes follows the sun by forty degrees and even more. Is there anyone who is not aware that from this assumption it necessarily follows that the diameter of the planet at perigee should appear more than four times, and the body of the planet more than sixteen times, as great as at apogee? Yet this variation is refuted by the experience of every age. In this science there are some other no less important absurdities, which need not be set forth at the moment. For this art, it is quite clear, is completely and absolutely ignorant of the causes of the apparent nonuniform motions. And if any causes are devised by the imagination, as indeed very many are, they are not put forward to convince anyone that they are true, but merely to provide a reliable basis for computation. However, since different hypotheses are sometimes offered for one and the same motion (for example, eccentricity and an epicycle for the sun’s motion), the astronomer will take as his first choice that hypothesis which is the easiest to grasp. The philosopher will perhaps rather seek the semblance of the truth. But neither of them will understand or state anything certain, unless it has been divinely revealed to him.

Therefore alongside the ancient hypotheses, which are no more probable, let us permit these new hypotheses also to become known, especially since they are admirable as well as simple and bring with them a huge treasure of very skillful observations. So far as hypotheses are concerned, let no one expect anything certain from astronomy, which cannot furnish it, lest he accept as the truth ideas conceived for another purpose, and depart from this study a greater fool than when he entered it.

Farewell."

Now here is the real behind-the-scenes story. Back in 1539 Georg Rheticus, a young mathematician, came to study with Copernicus as an apprentice. It was actually Rheticus who convinced the aging Copernicus to finally publish On the Revolutions of the Heavenly Spheres shortly before his death. When Copernicus finally turned over his manuscript for publication to Rheticus, he did not know that Rheticus subcontracted out the overseeing of the printing and publication of the book to a philosopher by the name of Andreas Osiander, and it was Osiander who anonymously wrote and inserted the infamous foreword. My guess is that Copernicus was a realist at heart who really did think that the Earth revolved about the Sun, while his publisher, who worried more about the public reaction to the book, took a more cautious positivistic position. I think that all scientific authors can surely relate to this story.

Another early example of the clash between positivism and realism can be found in Newton’s Principia (1687), in which he outlined Newtonian mechanics and his theory of gravitation, which held that the gravitational force between two objects was proportional to the product of their masses divided by the square of the distance between them. Newton knew that he was going to take some philosophical flak for proposing a mysterious force between objects that could reach out across the vast depths of space with no apparent mechanism, so he took a very positivistic position on the matter:

"I have not as yet been able to discover the reason for these properties of gravity from phenomena, and I do not feign hypotheses. For whatever is not deduced from the phenomena must be called a hypothesis; and hypotheses, whether metaphysical or physical, or based on occult qualities, or mechanical, have no place in experimental philosophy. In this philosophy particular propositions are inferred from the phenomena, and afterwards rendered general by induction."

Instead, Newton focused on how things were observed to move under the influence of his law of gravitational attraction, without worrying about what gravity “really” was.

Conclusion
So for the purposes of softwarephysics, it really does not matter whether the Universe is "actually" a quantum computer calculating how to behave or "actually" some kind of cosmic software running on some kind of cosmic computer. The important thing is that the Universe does indeed seem to behave like software running on a computer and that provides a very useful model for all of science to use. Perhaps such a model could provide some insights into Max Tegmark's Mathematical Universe Hypothesis as I outlined in The Software Universe as an Implementation of the Mathematical Universe Hypothesis. The Mathematical Universe Hypothesis proposes that the Multiverse is composed of all possible mathematical structures and that our Universe is just one of them and that includes all of the computable universes that can exist in software.

Comments are welcome at scj333@sbcglobal.net

To see all posts on softwarephysics in reverse order go to:
https://softwarephysics.blogspot.com/

Regards,
Steve Johnston

How to Study the Origin of Life on the Earth and Elsewhere in the Universe Right Here at Home

Over the past year, I have taken several excellent online courses on the origin of life on the Earth and elsewhere in the Universe. In all of these very interesting courses, I have noticed that as we go further and further back into deep time that it becomes ever harder to figure out exactly what might have happened. Indeed, this is very difficult to do because we only have one example of carbon-based life here on the Earth to examine. This is further complicated by the fact that none of these excellent courses have been able to definitively define exactly what life on the Earth is nor what life elsewhere in the Universe might look like. It is very difficult to determine the origin of something that cannot even be properly defined. That is why I have recommended in many of my softwarephysics posts to step up just one level higher first and begin by definitively defining the general concept of self-replicating information. Once that has been done we can then view carbon-based life on the Earth as just one of many forms of self-replicating information. Then we can proceed to explore the general characteristics of all forms of self-replicating information and also some possible commonalities that might exist with their origins.

Self-Replicating Information – Information that persists through time by making copies of itself or by enlisting the support of other things to ensure that copies of itself are made.

Over the past 4.56 billion years we have seen five waves of self-replicating information sweep across the surface of the Earth and totally rework the planet, as each new wave came to dominate the Earth:

1. Self-replicating autocatalytic metabolic pathways of organic molecules
2. RNA
3. DNA
4. Memes
5. Software

Software is currently the most recent wave of self-replicating information to arrive upon the scene and is rapidly becoming the dominant form of self-replicating information on the planet. For more on the above see A Brief History of Self-Replicating Information.

The Characteristics of Self-Replicating Information
All forms of self-replicating information have some common characteristics:

1. All self-replicating information evolves over time through the Darwinian processes of inheritance, innovation and natural selection, which endows self-replicating information with one telling characteristic – the ability to survive in a Universe dominated by the second law of thermodynamics and nonlinearity.

2. All self-replicating information begins spontaneously as a parasitic mutation that obtains energy, information and sometimes matter from a host.

3. With time, the parasitic self-replicating information takes on a symbiotic relationship with its host.

4. Eventually, the self-replicating information becomes one with its host through the symbiotic integration of the host and the self-replicating information.

5. Ultimately, the self-replicating information replaces its host as the dominant form of self-replicating information.

6. Most hosts are also forms of self-replicating information.

7. All self-replicating information has to be a little bit nasty in order to survive.

8. The defining characteristic of self-replicating information is the ability of self-replicating information to change the boundary conditions of its utility phase space in new and unpredictable ways by means of exapting current functions into new uses that change the size and shape of its particular utility phase space. See Enablement - the Definitive Characteristic of Living Things for more on this last characteristic. That posting discusses Stuart Kauffman's theory of Enablement in which living things are seen to exapt existing functions into new and unpredictable functions by discovering the “AdjacentPossible” of springloaded preadaptations.

By focusing on a definition of self-replicating information first and the common characteristics of all forms of self-replicating information, we eliminate the problems of trying to define “life” itself. In previous posts, I proposed that since carbon-based life on the Earth and software are both forms of self-replicating information, that it only makes sense to look to the origin and early evolution of software for some clues to the origin and early evolution of carbon-based life. For example, in the SoftwarePaleontology section of SoftwareBiology, I explained how the evolution of software over the past 78 years, or 2.46 billion seconds, ever since Konrad Zuse first cranked up his Z3 computer in May of 1941, has closely followed the same path through Design Space as did carbon-based life on this planet over the past 4.0 billion years in keeping with Simon Conway Morris's contention that convergence has played the dominant role in the evolution of life on Earth.

Software is now rapidly becoming the dominant form of self-replicating information on the planet and is having a major impact on mankind as it comes to predominance. So we are now living in one of those very rare times when a new form of self-replicating information, in the form of software, is coming to predominance. For biologists, this presents an invaluable opportunity because software has been evolving about 100 million times faster than living things over the past 2.46 billion seconds. And the evolution of software over that period of time is the only history of a form of self-replicating information that has actually been recorded by human history. In fact, the evolutionary history of software has all occurred within a single human lifetime, and many of those humans are still alive today to testify as to what actually had happened, something that those working on the origin of life on the Earth and its early evolution can only try to imagine.

As I saw in many of these courses, some are now trying to model the origin of carbon-based life on the Earth and elsewhere in the Universe with software. But why not just take advantage of the $10 trillion worldwide IT infrastructure that has been evolving all on its own for the past 2.46 billion seconds? Certainly, the biosphere of the Earth and this $10 trillion IT infrastructure are the most complicated information processing systems that we know of and billions of times more complicated than any research group could ever attain. Take a look at A Lesson for IT Professionals - Documenting the Flowcharts of Carbon-Based Life in the KEGG Online Database for example. The simplest way to do so would be to do some fieldwork in the corporate IT department of a major corporation or governmental agency. The objective of this fieldwork would be to observe the complexities of supporting heavy-duty commercial software in action on a network of hundreds of physical or virtual servers. I think that observing the IT processes that are used to write new code and install it into production on a large network of servers and then watching the emergent behaviors of the code under load would help researchers to understand the origins of carbon-based life and its complex information processing networks of organic molecules.

And there are tons of data for researchers to work with. Most large-scale IT operations have a great deal of monitoring software in place that displays and records the performance of many thousands of software components under processing load. For example, when I retired in December of 2016 my employer had about 500+ Unix servers running the software for their external websites and the internal web-based applications used to run the business. At peak load, these Unix servers were running several billion Objects (think eukaryotic cells) in Java Virtual Machines (JVMs) and all of these Objects (eukaryotic cells) were sending messages to each other, like the cells in a complex multicellular organism.

During an outage, the Command Center of the IT Department will page out perhaps 10 people to join an outage conference call. Then, using the display consoles of the monitoring software on their laptops the members of the outage call will all try to figure out what the heck is going on so that they can quickly fix the problem. Outages can cost between thousands to millions of dollars per second, depending on the business being conducted by the commercial software. Outages frequently happen in the middle of the night when new code goes into production or during the following day when the new code hits peak load. That would be an example of a simple deterministic outage caused by a low-level code change. But many times an outage just happens all on its own for no apparent reason. The whole network of information processes just seems to go berserk. Naturally, such “out of the blue” outages greatly displease IT Management because IT Management always wants to know the root cause of an outage. I spent many years trying to tell IT Management that such emergent outages just naturally arise for complex nonlinear networks far from thermal equilibrium but that explanation never went over very well. Anyway, the monitoring software records tons of data that can be used later to try and find the root cause of the outage. But this monitoring software runs continuously and provides a continuous stream of data that a research team could put to good use.

For a description of what a heavy-duty IT infrastructure looks like see Software Embryogenesis. For a more detailed post on such a proposal see A Proposal for an Odd Collaboration to Explore the Origin of Life with IT Professionals. In that post, I proposed that it might be worthwhile for researchers working on the origin of life or astrobiology to collaborate with the department of their university that teaches business-oriented computer science and with the IT department of a local major corporation or government agency to add some IT professionals to their research teams to bring in some new insights to their research efforts.

Some may object to the idea of software being a form of self-replicating information because currently, software is a product of the human mind. But I think that objection stems from the fact that most people simply do not consider themselves to be a part of the natural world. Instead, most people consciously or subconsciously consider themselves to be a supernatural and immaterial spirit that is temporarily haunting a carbon-based body. For more on that see The Ghost in the Machine the Grand Illusion of Consciousness.

In order for evolution to take place, we need all three Darwinian processes at work – inheritance, innovation and natural selection. And that is the case for all forms of self-replicating information, including carbon-based life, memes and software. Currently, software is being written and maintained by human programmers, but that will likely change in the next 10 – 50 years when the Software Singularity occurs and AI software will be able to write and maintain software better than a human programmer. Even so, one must realize that human programmers are also just machines with a very complicated and huge neural network of neurons that have been trained with very advanced Deep Learning techniques to code software. Nobody learned how to code software sitting alone in a dark room. All programmers inherited the memes for writing software from teachers, books, other programmers or by looking at the code of others. Also, all forms of selection are “natural” unless they are made by supernatural means. So a programmer pursuing bug-free software by means of trial and error is no different than a cheetah deciding upon which gazelle in a herd to pursue.

Conclusion
In The Danger of Believing in Things, I discussed what can happen when a science gets "stuck" on a problem that seems impossible to solve. Sometimes the best thing to do when apparently "stuck" is to simply walk away from the problem for a bit and seek the advice of others, especially others with an entirely different perspective of the problem at hand.

Comments are welcome at scj333@sbcglobal.net

To see all posts on softwarephysics in reverse order go to:
https://softwarephysics.blogspot.com/

Regards,
Steve Johnston