Tuesday, 12 May 2015

Published Elsewhere: Physics is Always Right and Always Wrong

[As promised, this is the second article of mine I have dug up. I had written this piece sometime in 2013, when I was in the second year of my undergraduate course, for the alumni magazine of my high school]

Physics is Always Right and Always Wrong

On what scientific attitude really is

George Bernard Shaw once said, "Science is always wrong. It never solves a problem without creating ten more." He was absolutely right. Science is always wrong. I have to say that science has to be always wrong. Indeed, in its very capability of being always wrong does lie the essential rightness of science. That is also precisely what distinguishes it from any religion or dogma which must be true because, well, it has to be true. So it naturally follows that in science there is neither any sacred text, nor any god sitting atop Mount Olympus. But there do exist some very fundamental principles and some giants on whose shoulders we must support ourselves, and rise higher.

A very recent example will make it clearer. In September 2011, the physicists conducting the OPERA experiment (Oscillation Project with Emulsion-tRacking Apparatus) in Italy sent shockwaves through the scientific world by announcing the stunning results of their experiments with neutrino, an electrically neutral, almost massless fundamental particle. The result of their experiments suggested that the neutrinos were travelling faster than light! It was violating one of the most well known rules in all of physics, one of the two fundamental postulates formulated by Albert Einstein in his path-breaking special theory of relativity in 1905.

Naturally, the results got widespread public attention. How could it be possible? How could Einstein, the very epitome of genius, be proven wrong? I remember not-very-helpful comments on social networking sites to the effect of: "Physicists pretend that they know everything and physics is ultimate. If Einstein is wrong, physics loses all its credibility and authority. We should therefore not believe in physics and turn our attention to [something else]." The physics community received the news with immense scepticism, voiced its serious doubts on the result and repeatedly emphasised the need for further experiments before making arriving at any conclusion. These two views perfectly illustrate the difference between physics and "something else".

The physicists were not concerned with the results violating physical laws formulated by Einstein simply because they came from Einstein. They were sceptical because Einstein’s theory has been verified by hundreds of experiments and thus has become a central pillar of modern physics. Experimenting is what lies at the root of a natural science like physics. (Do look up what Richard Feynman, arguably the most famous theoretical physicist on the twentieth century, had to say about the definition of natural science in the Feynman Lectures.) It is the experimental results which guide the physicists and the physicists, in turn, decide which way the experiments should proceed. Even the most abstract parts of theoretical physics have to be consistent with and sometimes constrained by experimental results. Physics is all about knowing how nature behaves and nature reveals herself to us through experiments. It is a mistake to assume that physicists dictate what nature is. It is nature which comes first in the study of physics, not our idealisation about her. One can further say that physics is not only about what we know, it is also about what we do not know. Indeed, testing the boundaries of human knowledge is what gives physics its strength. In fact, no physical law is ever exactly true, so to speak  it is only our approximation of the truth. But the fact that physics is not exactly true does not mean that it cannot take us closer and closer to the truth. All idea of scientific progress actually rests on that fact.

If we now look at how Einstein himself and other great physicists of his time (including Max Planck) who expanded the horizons of our knowledge, it will be apparent that their theories did not negate the classical theory so much as add to it and show the limits of its applicability. For more than two centuries, classical physics (as formulated by Newton) remained the pillar of natural science, again because it had survived so much of experimental scrutiny. Around the turn of the new century, certain experimental results suggested that the classical laws were insufficient in describing nature, necessitating the need for newer, more generalised theories, namely the theory of relativity and quantum mechanics. The counterintuitive results were as shocking to the physicists of that time as the neutrino results were to the physicists of our time. In fact, Max Planck, the man who put forward the quantum theory, was stunned by some implications of his own theory. But again, all these theories have survived the test of time and experiment. More advanced theories have been developed, further deepening our knowledge. But all physicists still recognise the genius of Newton and his scientific method, while building on it. Einstein himself referred to Newton as a "man of highest thought and creative power" of his age. Indeed, Newtonian laws describe nature in certain limited ways (large bodies with speeds much less than that of light) to a remarkably high degree of accuracy.

This brings us back to the neutrino experiment. It later turned out, surely to the dismay of such social network users as described above, that the experimental results were incorrect and it was attributed to an incorrectly fitted wire. But for argument’s sake, let’s say the results were confirmed to be correct. What would we have done then? Should we have thrown everything that went before it to the dustbin? Absolutely not! Instead, we would stand on the shoulder of the giants and broaden our understanding of nature. Yes, physics is always wrong, but it is always right too!

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