Imagination is limited, not physics

Science prides itself on the successes its theories have in predicting the outcome of events in the laboratory or in nature.

But the success rate of experts predicting the future of science has had several glitches. It is interesting (and desirable?) to remind ourselves of some of the mistaken prophesies.

Simon Newcomb (1835-1909), himself a distinguished mathematician and astronomer, had these derogatory comments to make on human attempts to make flying machines:

The demonstration that no possible combination of known substances, known forms of machinery and known forms of forces can be united in a practical machine by which man shall fly long distances through the air, seems to the writer as complete as it is possible for the demonstration of any practical fact to be.

No less a person than Thomas Edison back in 1889 expressed skepticism about the use of alternating currents at high tension (voltage). He had recommended that their use be abolished as they are dangerous to life and property. Nikola Tesla won the “War of the Currents” and proved otherwise.

When Robert Goddard was conducting research on rockets, his experiments initially failed, as can happen in any new technology.

At that stage he received “friendly” advice from several friends to desist. The well-known flyer of aircraft, Charles Lindbergh, advised him: I would much prefer to have Goddard interested in real scientific development than to have him primarily interested in more spectacular achievements which are of less real value.

Perhaps one of the most well known expert comments was by Admiral William Leahy to President Truman as the atom bomb was being tried: This is the biggest fool thing we have ever done. The bomb will never go off, and I speak as an expert on explosives.

Ironically, for a different reason, many persons today would agree with Leahy’s first sentence even though, and because, the bomb was a technical success. It was to set in motion a race towards nuclear arms with increasing power of destruction.

These are some examples of how people even in important positions, and with lot of experience to count on, misjudged the potential of a new scientific discovery. But it has been the case that even professional scientists have been misled by their prejudices.

Take the case of Isaac Newton, arguably the most important physicist in the history of science. Despite the many successful discoveries to his credit, from the laws of motion, the law of gravitation, the splitting of sunlight into seven colours, the propagation of sound, to calculus, a new branch of mathematics, modelling the universe, etc.,

Newton refused to believe that light propagates as a form of wave motion. He refused to believe the evidence that could not be explained by any other theory, including Newton’s own favourite, the corpuscular theory.

Indeed, workers on theories of light were discouraged from proceeding in a direction believed to be wrong by Newton and progress in that branch of science was held off until he was no more.

Three centuries later, it was Albert Einstein who could not reconcile his beliefs with what the newly emergent quantum theory talked about.

This is in a way surprising because Einstein himself had introduced concepts which others had found hard to believe such as the different rates at which clocks measured the passage of time depending on how fast they were moving; or the idea that a light ray should be bent by the gravitational pull of a nearby massive object; or the limit of the speed of light imposed on all causal influences propagating across large distances.

However, the debate on the foundations of quantum theory between Einstein and Niels Bohr very clearly brings out Einstein’s discomfort at the “strange” ways in which measurements and motions of microscopic particles had to be handled and the restriction imposed by nature on these concepts.

Geoffrey Burbidge, a distinguished astrophysicist who passed away a few years back, used to comment on the tendency of scientists in the closing years of a century to converge on a belief that most of the important science is now discovered and known and that what remains is not very important.

This was first experienced in the retiring days of Newton, after his discoveries had explained such outstanding phenomena as planetary motion, why comets come and go, and many others.

Thus towards the end of the 17th century motion and gravitation were at the forefront of observed phenomena and their understanding led to the belief in the end of physics.

However, new problems surfaced in the 18th century as well as the discovery of electromagnetic forces. While these brought a temporary expectation that the end of physics would be reached soon, the 19th century expanded the physicist’s horizon still further.

After progress in electrodynamics by Maxwell and Faraday, and in thermodynamics by Sadi Carnot and Lord Kelvin, it was again argued that the end of physics would soon come by the turn of the century.

Alas, here too surprises were in store. Relativity and quantum theory brought new revolutions and inspired more adventurous approaches to fundamental physics.

Optimism about reaching the goal of total understanding led to such high-sounding names as “grand-unified theory” or “the theory of everything”. The 20th century came and went and so far in the 21st century the feeling of reaching the end has not yet come.

Perhaps the last word rests with Fred Hoyle, the most imaginative scientist of the 20th century. He cautioned that it is very unlikely that the human brain will ever have the capacity of understanding physics in its totality; and if it did, then it was very unlikely to have happened in our lifetime.

He made this statement in 1970, when several scientists were claiming to have solved the riddle of the origin of the universe. Since then ideas on the same topic have radically changed, thus amply justifying his caution.

In short, while scientists need to retain their optimism about reaching the end of their quest, they should be aware that the currently perceived end of the quest may not be the end of physics.

The writer, a renowned astrophysicist, is professor emeritus at Inter-University Centre for Astronomy and Astrophysics, Pune University Campus