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Theories, or flights of imagination?
“ THE American philosopher Charles Sanders Pierce somewhere remarked that unfortunately universes are not as plentiful as blackberries. One of the most astonishing of recent trends in science is that many top physicists and cosmologists now defend the wild notion that not only are universes as common as blackberries, but even more common. Indeed, there may be an infinity of them.” — Martin Gardber
The seeds of the Many Worlds Interpretation (MWI) were sown in 1957 with the PhD thesis of Hugh Everett III, who earned it at Princeton under the supervision of the celebrated physicist and cosmologist, John Wheeler. The objective was to do away with the Copenhagen Interpretation and quantum measurement (observation) problem.
If an event — say, the tossing of a coin — has more than one outcomes, the various outcomes exist with their associated probabilities in a wave function, which collapses when a measurement is taken, according to the Copenhagen Interpretation. This interpretation was considered unsatisfactory, shallow and superficial by many physicists.
To do away with the collapsing of the wave function at the instant of measurement, Everett suggested that various outcomes exist in various different worlds (universes), which are as real (or illusory) as our own. When a coin is tossed, our universe immediately splits into two parallel universes. In one of them, the coin falls face up and in the other, it falls tail up. By the same logic, Schrodinger’s legendary cat is dead in one universe and alive in the other.
If there are more than two outcomes of a given event — the coin falling sideways, for instance — the universe splits up into as many universes as there are outcomes. These universes contain, not only the outcomes of the event, but they also have a copy of you (doppelganger) and the associated equipment. Your copy is only nominally different from you.
As a consequence, our universe is splitting up all the time into an infinite number of other universes and they are as real as our own. However, we cannot communicate with other universes.
What can be more bizarre than this? This is not mere theoretical speculation, as many distinguished physicists actually believe in this. If there ever was a pressing need for empirical verification, it is for such cosmological theories.
Can these theories be tested and empirically verified? Well, a majority of physicists agree that they cannot be verified directly. However, the proponents, mostly theoreticians, believe that some indirect verification will be possible in future.
What is a parallel universe? It is a universe that splits from its parent universe and is similar to it at its creation, but may evolve differently later. There are many puzzling questions about this concept, though.
Our universe came into existence some 14 billion years ago as a result of the Big Bang. And it is considered to be infinite in size.
The visible universe — which is at least 14 billion light years large and which is still expanding at a variable rate — is believed to be only a tiny part of the whole universe that includes the “invisible expanse.” How can another universe come into existence instantly with the toss of a coin?
That is not all. According to Jim Holt, “Physicists who buy into this interpretation (MWI) — and many distinguished ones do — claim that each universe splits into something like 10^100 copies every second, all of them equally real. Yet, since quantum theory forbids these parallel worlds from interacting, there is no experimental way to confirm their reality.”
How big is 10^100? It is 1 followed by 100 zeroes. So many universes come into being every second. Phew! This is not physics, but metaphysics, pure and simple.
Another thing. I never felt so infinitely empowered as this theory made me, because with the flip of a coin I can split my universe and create another “parallel universe.” Physicists refuse to give this power to God. They don’t even accept that God created our universe and others, if any. Yet you can create as many as you like by flipping coins.
In one of my earlier papers — titled “Physical theory and empirical verification” which was published online — I had written: “As more and more diverse phenomena were related in the threads of mathematical theories, these theories became ever more sophisticated and complex. For this reason, they were getting farther and farther from the comprehension of a common person.
“In order to be able to comprehend Maxwell’s theory of electromagnetism and Newton’s theory of gravity, for instance, disciplined education in a school and college is required for many years.”
Theories of relativity and quantum mechanics are much more complex than the theories of gravitation and electromagnetism. Many physicists find it hard to think, in terms of the four dimensional space-time, what to say of ten or eleven dimensions of string theories.
The theoretical physicist and popular science writer Paul Davies confessed in his book The Matter Myth that even though he understood the mathematics behind the theories of relativity, it was very hard for him to understand the inherent physical reality of the relativistic time and space-time. He does not say if he understands it now.
We are at a stage where we can construct sophisticated mathematical theories and successfully use them for making predictions but we are unable to have realistic insights into the physical reality of the predicted events and phenomena. Considered in this perspective, the MWI may be a useful contrivance to do away with the Copenhagen Interpretation. Its extension to the real parallel universes, however, appears to be intellectual “hogwash.”
If, however, physical reality is just an illusion then anything goes. According to Martin Gardner, “If all these countless billions of parallel universes are taken as no more than abstract mathematical entities — worlds that could have formed but didn’t — then the only “real” world is the one we live in. In this interpretation of the MWI the theory becomes little more than a new and whimsical language for talking about quantum mechanics (QM). It has the same mathematical formalism and makes the same predictions.
“This is how Hawking and many others, who favour the MWI, interpret it. They prefer it because they believe that it is a language which simplifies QM talk and also sidesteps many of its paradoxes.”
Commenting on parallel universes, Fred Alan Wolf, a theoretical physicist and a popular writer, wrote: “In the old physics, this was nothing more than a technical problem. The electron had a single location — it had to be somewhere — and your job was just to find it. But in the new quantum physics, the electron has no definite position or, in other words, it has all possible positions simultaneously. But, in a self-consistent manner, each possibility must exist in a separate universe. When you find it, each of those possibilities manifests simultaneously. That’s right, all infinity of them.
“In each possibility or, if you grant me the licence, universe, there will appear a single electron and a single viewpoint - your own… . Yet, surprisingly nothing strange is going on. No splitting is felt. In fact, all the splitting occurs only in your brain.”
Nevertheless, the idea of many worlds, or multiple universes, caught on. The new developments, for instance the string theory and the initial inflation of our evolving universe, led to the formulation of the concept of coming into being of countless other universes. Our universe began from a tiny bubble, which exploded with a big bang. It is theorized that countless similar bubbles explode every second as a consequence of quantum fluctuations in the pre-existing space-time that is called the multiverse — a universe enveloping all other universes. Billions of new universes are born every second.
All these universes have their own universal laws with different values of the cosmic constants. The majority of these universes are incapable of supporting life as we know it — they are just out there. Our universe is “finely tuned” in the sense that if its constants had slightly different numerical values, life wouldn’t have evolved here. This is called the anthropic principle.
Creation scientists use this principle to justify the existence of God, who is responsible for creating our universe with divine intelligence, with just the right values for the various constants. Physicists balk at this suggestion and assert that our universe is the result of a lucky accident. Among a myriad of other universes, there is a probability for all the constants to have all kinds of values. Our universe happens to have just the right values for the successful evolution of life. All these other universes exist out there somewhere in space-time, but we don’t have the means to detect or communicate with them.
The original theory of inflation was developed by Alan Guth, but soon after its publication he realized that there were some loose ends in it, which needed to be taken care of properly. A. Linde, besides several others, also found these weaknesses. Linde published his theory, which he called the New Theory of Inflation.
The new theories, as it transpired later on, had weaknesses of their own. Finally, Linde developed his Theory of Chaotic Inflation. This has found favour with many distinguished physicists and cosmologists. For instance, Steven Weinberg commented on it as follows: “Chaotic Inflation opens up the possibility I mentioned earlier, of a new view of what happened before our big bang. If the scalar fields don’t evolve …everywhere in the universe, there may have been other big bangs before our own, and there may be yet to come. Meanwhile, the whole universe goes on expanding, so there is always plenty of room for more big bangs. Thus, although our own big bang had a definite beginning about ten to fifteen billion years ago, the bubbling up of new big bangs may have been going on for ever in a universe that is infinitely old.”
The concept of multiple universes is a consequence of the string theory. According to Lenny Susskind, “The reason that there is so much diversity in string theory is it has enormous number of what I call moving parts, things you can tinker with.”
Much of it is largely theoretical speculation; however this shows the direction in which the present thinking is pointing to. Speculation is an essential ingredient of theoretical research.
According to Wolf, “The main problem in quantum physics is its interpretation. How can we believe that there exist numerous universes, one appearing every time anyone happens to observe something? And further, that these universes are not just possibilities, but possibilities that somehow conspire to produce the world we do experience.”
One thing that needs to be clarified here is that the concept of parallel universes has nothing to do with the multiplicity of universes indicated by chaotic inflation. The parallel universes were conjectured to resolve the undesirable issue of the collapse of wave function, which was at the foundation of the Copenhagen Interpretation. The multiple universes are the result of big bangs occurring in countless bubbles (like our universe) existing in the invisible universe.
The former is a consequence of the present inadequacy of knowledge to satisfactorily explain the “measurement (observation)” problem and the latter is a speculation from the Chaotic Inflation theory. The inflation theory was formulated by Guth in the late 1970s while the parallel universe hypothesis was given in 1957, as already mentioned.
The writer has a PhD in civil engineering from the University of London. His email address is akramgill@yahoo.com
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