Science and Scientists
As somebody said, science is what scientists do. And scientists are human too. Some of these humans have great difficulty in reconciling what science tells them with what they learnt from various sources when they were young and impressionable. So they may unconsciously look for ‘loopholes’ in the scientific premises and reasoning, particularly when it comes to fundamental questions about life, mind, and the universe.
In science there is always a cutting edge, or the frontier line where things are hazy. There is debate among experts as various alternative models are compared and contrasted. The beauty of the scientific method is that it is ruthless and without regard for authority (but see below!). Truth prevails ultimately, sometimes after a prolonged debate about what is the best way of interpreting the available data. When more data come in, science has no difficulty in dumping even its most cherished theories if necessary.
Sometimes, of course, the debate continues endlessly. This is particularly true for the highly counterintuitive quantum theory. To me the most important thing about this theory is that it has been phenomenally successful in explaining a vast multitude of natural phenomena, even though we do not have all the answers. Science accepts it because there is no better theory known to us that can be more successful for explaining what we see in the world around us.
To me it is not important that the quantum theory is counterintuitive. I see no reason why the laws of Nature should be always comprehensible to us. We emerged on the cosmic scene very very recently, but the laws of Nature have been there all the time.
But, as I said, scientists are human too. They do have their failings and weaknesses and gut feelings. We all know about Einstein’s reservations about the quantum theory of his day. But tomorrow if Einstein turns out to be right, no problem. We would then have an even better theory at hand. That is how science progresses.
2. The Copenhagen interpretation
There was this well-known debate between Einstein and Born about the foundations of quantum mechanics. Bohr’s viewpoint prevailed, and this gave him enormous, even undue, authority in scientific circles. If a proof is needed, look at the so-called ‘Copenhagen interpretation’ (CI) of quantum mechanics he gave in 1927, jointly with Heisenberg (another venerated scientist). According to the CI, people and the equipment they use exist in a classical world which is different from the quantum world. A quantum state is a superposition of two or more states, but when it interfaces with the classical world (at the moment of measurement), there is a collapse of the wave function (randomly) to one of the alternatives, and the other alternatives disappear. It was put in ‘by hand’ as an additional postulate of quantum mechanics.
I have given some more details of the CI in an article on ‘biocentrism’ I coauthored with Ajita Kamal, published at Nirmukta.com:
What was done was to juxtapose the CI with a number of later interpretations. To me it is clear that the CI has been superseded by better interpretations. So much for science. Now let us look at the scientists part of it.
Among the earliest persons to openly challenge the CI was Hugh Everett III, when he put forward his ‘many worlds’ interpretation. But on the scientific scene at that time he was just a kid (a student at Princeton University in the mid-1950s) compared to stalwarts like Bohr and Heisenberg. [To us in India this is reminiscent of the Chandrasekhar vs. Eddington episode in cosmology.] A. H. Wheeler was the Ph.D. supervisor of Everett. Peter Byrne has written about this story in an article in the December 2007 issue of Scientific American. In 1956 Wheeler took the draft dissertation of Everett’s thesis to Copenhagen to convince the Royal Danish Academy of Sciences to accept it and publish it. He had ‘three long and strong discussions about it’ with Bohr and Petersen. He also showed the work to many others at the Bohr Institute for Theoretical Physics, including A. S. Stern.
Stern dismissed the work as ‘theology’, and Wheeler himself was reluctant to challenge Bohr. The thesis had to be whittled down to a quarter of its original length. This abridged version also appeared in Reviews of Modern Physics. Young Everett eagerly looked forward to the reactions of the physics community. All he got was stony silence, so much was the awe that the name Bohr inspired (and that continues in some quarters even today). Discouraged, Everett left physics and worked on military and industrial mathematics and computing. As the Editors of Scientific American wrote, ‘He died when he was just 51, not living to see the recent respect accorded to his ideas by physicists.’
Bohr, of course, was quite consistent in his views about the basics and limitations of quantum mechanics. This came to the fore again in his reaction to Einstein and others’ views on ‘quantum entanglement.’ Now this is an esoteric feature of quantum mechanics that again challenges our intuition very seriously. And yet there is no immediate danger to the present edifice and acceptability of quantum theory. Why? The answer comes from experiment, namely the fact of life that quantum computing is already a reality.
The entanglement feature of quantum mechanics is about the spooky ‘action at a distance’: Two particles behave synchronously without any intermediary, no matter how far apart they are. This nonlocality feature bothered Einstein and others, as embodied in the famous EPR (Eistein-Podolsky-Rosen) thought experiment published in 1935 in a paper with title ‘Can Quantum-Mechanical Description of Physical Reality Be Considered Complete?’ EPR argued that the answer to the question is ‘No.’ They took the position that nonlocality is not something real, and therefore quantum mechanics does not provide a complete description of reality.
Bohr did agree with this conclusion, but for his own reasons (see, for example, the article by Albert and Galchen in the March 2009 issue of Scientific American). He argued that we should not even try to read from the equations of quantum mechanics a realistic comprehension of the world. This was in line with what he did in the Copenhagen interpretation mentioned above; namely, introduce one more postulate or axiom by hand when interfacing the microworld with the macroworld.
Thirty years later John Bell wrote his famous paper in which he established by mathematical proof that the real physical world is indeed nonlocal, no matter what EPR or Bohr believed to be the case. He showed that no local (as opposed to nonlocal) theory can reproduce all the predictions of quantum mechanics because the predictions must always satisfy the now-famous Bell’s inequalities. This meant that the concept of locality was indeed incompatible with quantum theory, so the actual physical world in indeed nonlocal. Both Einstein and Bohr were wrong, though for different reasons.
The influence of Bohr’s line of thinking was so strong and persistent that there was resistance to Bell’s work also. But this situation has changed gradually. I quote from Albert and Galchen (2009): ‘From the early 1980s onward, the grip of Bohr’s conviction -- that there could be no old-fashioned, philosophically realistic account of the subatomic world -- was everywhere palpably beginning to weaken.’
(Continued in Part 2)