Brilliant Blunders: From Darwin to Einstein - Colossal Mistakes by Great Scientists That Changed Our Understanding of Life and the Universe (39 page)

The second main reason for the hostile passions that anthropic reasoning provokes is that to some scientists it signals the “end of physics.” Following Descartes, most physicists dream, above all, of a uniquely self-consistent mathematical theory that explains and determines all the microphysical constants, as well as the entire cosmic evolution. Consequently, they would like to pursue, in the words of cosmologist Edward Milne, “a single path towards the understanding of this unique entity, the universe.” There is very little doubt that this was Einstein’s hope too.
In a lecture delivered at Oxford in 1933, Einstein said, “It is my conviction that pure mathematical construction enables us to discover the concepts and the laws connecting them which give us the key to the understanding of the phenomena of Nature.” As is well known, Einstein was uncomfortable even with the probabilistic nature of quantum mechanics, though he appreciated fully its successes. In a letter he wrote on December 4, 1926, to Max Born, one of the founding fathers of quantum mechanics, Einstein expressed his opinion:

Quantum mechanics is certainly imposing. But an inner voice tells me
that this is not yet the real thing
[emphasis added]. The theory yields much, but it hardly brings us closer to the Old One’s secrets. I, in any case, am convinced that He does not play dice.

The concept of accidental variables in a potentially unobservable multiverse would have probably distressed Einstein even more.
Note, however, that Einstein’s reservations about quantum mechanics stemmed more from psychology—his belief that he knew the direction in which to look—than from hard-core physics. The same may turn out to be the case with the objections to anthropic reasoning. In spite of the experience in the past few centuries, there are no assurances that physical reality will indeed oblige and render itself in its entirety to first-principles explanations. The quest for such descriptions may prove as futile as Kepler’s quest for a beautiful geometrical model for the solar system. What we have traditionally called fundamental constants and maybe even laws of nature could turn out to be mere accidental variables and parochial bylaws in our universe. The anthropic principle could perhaps eventually play a similar role to that assigned by philosopher Bertrand Russell to philosophy: “The point of philosophy is to start with something so simple as to seem not worth stating, and to end with something so paradoxical that no one will believe it.”

The anthropic thinking on the nature of the cosmological constant demonstrates the profound impact that Einstein’s seemingly innocent attempt at a static universe continues to have on cutting-edge physics. How then do we appraise Einstein’s “biggest blunder” today?

The year 1905 is often called Einstein’s annus mirabilis (“miracle year”), since during that year he published his trailblazing papers on how light knocks electrons off metals (the “photoelectric effect,” which spawned quantum mechanics and won him the Nobel Prize), on random drifting of particles suspended in a fluid (“Brownian motion”), and on the theory of “special relativity.” While 1905 was indeed a year of wonders for Einstein, he actually had a second annus mirabilis (fifteen months, to be exact) from November 1915 to February 1917. During this period, he published no fewer than fifteen treatises, including the brilliant pinnacle of his work—general relativity—and two significant contributions to quantum
mechanics. Modern cosmology, and with it the cosmological constant, were born.

I hope that the evidence presented in chapter 10 has convinced the reader that most probably Einstein never used the expression “biggest blunder.” Moreover, the introduction of the cosmological constant was not a blunder at all, since the principles of general relativity gave the green light for such a term. Thinking that the constant would ensure a static universe was definitely a regrettable mistake but not one that would qualify as a “blunder” of the magnitude considered in this book. Einstein’s true blunder was to
remove
the cosmological constant! Mind again that removing the term from the equations is tantamount to arbitrarily assigning the value
zero
to lambda. In doing so, Einstein restricted the generality of his theory—a high price to pay for the conciseness of the equations, even before the recent discovery of the cosmic acceleration.

Simplicity is a virtue when it applies to the fundamental principles, not to the form of the equations. In the case of the cosmological constant, Einstein mistakenly sacrificed generality on the altar of superficial elegance. A simple analogy can help to clarify this concept. When Kepler discovered that the planetary orbits were elliptical rather than circular, the great Galileo Galilei refused to believe it. Galileo was still prisoner to the aesthetic ideals of antiquity, which assumed that the orbits had to be perfectly symmetrical. Physics has shown however that this was an unjustified prejudice. The symmetry involved actually runs much deeper than the mere symmetry of shapes. Newton’s law of universal gravitation states that the elliptical orbits (which are a natural consequence of this law) can have any orientation in space. In other words, the law doesn’t change whether we measure directions with respect to the north, south, or the nearest star—it is symmetric under rotations. When Einstein dubbed the cosmological constant “ugly,” he was equally biased and shortsighted. He should have instead stuck with his initial instinct that a day would come “for us to be able to decide empirically the question of whether or not Λ vanishes,” as he wrote to de Sitter. That day came in 1998.

More than 20 percent of Einstein’s original papers contain mistakes of some sort. In several cases, even though he made mistakes along the way, the final result is still correct. This is often the hallmark of truly great theorists: They are guided by intuition more than by formalism. In a letter he wrote on February 3, 1915, to the Dutch physicist Hendrik Lorentz, Einstein provided his own perspective on mistakes in scientific theories:

A theorist goes astray in two ways:

1. The devil leads him by the nose with a false hypothesis. (For this he deserves our pity.)

2. His arguments are erroneous and sloppy. (For this he deserves a beating.)

Even though Einstein himself certainly committed errors of both types, his unparalleled physical insight showed him, in many cases, the path to the right answers. Unfortunately, we mere mortals can neither imitate nor acquire this talent.

In 1949
Einstein’s collaborator Leopold Infeld described Einstein’s pioneering paper on cosmology this way:

Although it is difficult to exaggerate the importance of this paper . . . Einstein’s original ideas, as viewed from the perspective of our present day, are antiquated if not even wrong . . . Indeed, it is one more instance showing how a wrong solution of a fundamental problem may be incomparably more important than a correct solution of a trivial, uninteresting problem.

Infeld’s essay appeared in a volume in Einstein’s honor entitled
Albert Einstein: Philosopher-Scientist.
No fewer than six Nobel laureates in science contributed to this book. In his contribution,
Georges Lemaître described what he regarded as strong reasons for keeping the cosmological constant in the equations: “
The history of science provides many instances of discoveries which have been made for reasons which are no longer considered satisfactory. It may be that the discovery of the cosmological constant [by Einstein] is such a case.” How right he was.

Einstein himself remained unconvinced. In his “Remarks Concerning the Essays Brought Together in This Co-operative Volume,” he repeated his earlier arguments:

The introduction of such a constant implies a considerable renunciation of the logical simplicity of [the] theory, a renunciation which appeared to me unavoidable only so long as one had no reason to doubt the essentially static nature of space.

He continued to say that after Hubble’s discovery of the cosmic expansion and Friedmann’s demonstration that the expansion could be accommodated in the context of the original equations, he found the introduction of lambda “at present [in 1949] unjustified.” Note, by the way, that even though Einstein wrote these comments not long after his correspondence with Gamow, there is still no allusion to “biggest blunder.”

On one hand, you could argue that Einstein was right in refusing to add to his equations a term that was not absolutely required by the observations. On the other, Einstein had already missed one opportunity to predict the cosmic expansion by relying on the lack of evidence for stellar motions. By denouncing the cosmological constant, he missed a second opportunity, this time to predict the accelerating universe! With any ordinary scientist, two such oversights would surely have been regarded as lack of intuition—something we can hardly conclude about Einstein.
Einstein’s failures remind us that human logic is not blunder proof, even when exercised by a monumental genius.

Einstein kept thinking about a unified theory and the nature of
physical reality until the end of his life. Already in 1940, he foresaw the difficulties with which current string theorists struggle: “The two systems [general relativity and quantum theory] do not directly contradict each other; but they seem little adapted to fusion into one unified theory.” Then, just one month before his death, in 1955, at the age of seventy-six, he added some self-doubts: “It appears dubious whether a [classical] field theory can account for the atomistic structure of matter and radiation as well as of quantum phenomena.” Einstein did, however, find some comfort in the words of the eighteenth-century dramatist Gotthold Ephraim Lessing: “
The aspiration to truth is more precious than its assured possession.” Blunders and all, perhaps no one in recent memory has aspired to truth more than Albert Einstein.

I would earnestly warn you against trying to find out the reason for and explanation of everything . . . To try and find out the reason for everything is very dangerous and leads to nothing but disappointment and dissatisfaction, unsettling your mind and in the end making you miserable.

—QUEEN VICTORIA

No scientific theory has an absolute and permanent value. As experimental and observational methods and tools improve, theories can be refuted, or they may metamorphose into new forms that incorporate some of the earlier ideas. Einstein himself stressed this evolutionary nature of theories in physics: “The most beautiful fate of a physical theory is to point the way to the establishment of a more inclusive theory, in which it lives as a limiting case.” Darwin’s theory for the evolution of life by means of natural selection was only strengthened through the application of modern genetics. Newton’s theory of gravity continues to live as a limiting case within the framework of general relativity. The road to a “new and improved” theory is far from smooth, and progress is definitely not a headlong rush to the truth. If luminaries such as Darwin, Kelvin, Pauling, Hoyle, and Einstein can commit serious blunders, imagine the scorecards of lesser scientists. When James Joyce wrote in
Ulysses,
“A man of genius makes no mistakes. His errors are volitional and are the portals of discovery,” he meant the first part of his comment to be provocative. As we have seen in this book, however, the blunders of genius are often indeed the portals of discovery.

In director Rob Reiner’s 1987 fairy-tale film
The Princess Bride,
one of the characters engages in a battle of wits against the protagonist. At one point, he exclaims, “You fell victim to one of the classic blunders! The most famous of which is ‘never get involved in a land war in Asia.’ ” I think we can all agree that recent history has shown this statement to be good advice. The famous mathematician and
philosopher Bertrand Russell suggested another tip to those who want to make sure they avoid fanaticism: “Do not feel absolutely certain of anything.” The examples in this book demonstrate that this “commandment” can also be taken as a useful hint for how to dodge major blunders—but I am not absolutely certain about this . . . While doubt often comes across as a sign of weakness, it is also an effective defense mechanism, and it’s an essential operating principle for science.

Kelvin, Hoyle, and Einstein revealed yet another fascinating side of human nature. Just as people (scientists included) are sometimes reluctant to admit their mistakes, they also on occasion stubbornly oppose new ideas. Max Planck, one of the forefathers of quantum mechanics, once remarked cynically, “New scientific truth does not triumph by convincing its opponents and making them see the light, but rather because its opponents eventually die, and a new generation grows up that is familiar with it.” This may be sad but true.