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

Page 22

by Livio, Mario


  Hoyle, on the other hand, continued to advocate a somewhat modified version of the steady state theory (which he called “quasi–steady state”). Even as late as the year 2000, at the age of eighty-five, he published a book entitled A Different Approach to Cosmology: From a Static Universe Through the Big Bang Towards Reality, in which he and his collaborators, Jayant Narlikar and Geoff Burbidge, explained the details of the quasi–steady state theory and their objections to the big bang. To express their contemptuous opinion of the scientific establishment, they presented in one of the book’s pages a photograph of a flock of geese walking on a dirt road with the caption, “This is our view of the conformist approach to the standard (hot big bang) cosmology. We have resisted the temptation to name some of the leading geese.” By then, however, Hoyle had been out of the conventional cosmological wisdom for so long that very few even bothered to point out the shortcomings of the modified theory. Perhaps the best thing said about the book appeared in the review by Britain’s Sunday Telegraph, and it referred not so much to the contents of the book as to Hoyle’s fiery personality: “Hoyle systematically reviews the evidence for the Big Bang theory, and gives it a good kicking . . . it’s hard not to be impressed with the audacity of the demolition job . . . I can only hope that I possess one-thousandth of Hoyle’s fighting spirit when I, like him, have reached my 85th year.”

  Dissidence and Denial

  Hoyle’s blunder was somewhat different from those of Darwin, Kelvin, and Pauling in two important respects. First, there was the issue of the scale of the topic, in the context of which the blunder occurred. Darwin’s blunder involved only one element of his theory (albeit an extremely important one). Kelvin’s blunder concerned an assumption at the basis of a particular calculation (a very meaningful one). Pauling’s blunder affected one specific model (unfortunately for the most crucial molecule). Hoyle’s blunder, on the other hand, concerned no less than an entire theory for the universe as a whole. Second and more important, Hoyle did nothing wrong in proposing the steady state model—unlike Darwin, who did not understand the implications of a faulty biological mechanism; Kelvin, who neglected unforeseen physical processes; and Pauling, who ignored basic rules of chemistry. The theory itself was bold, exceptionally clever, and it matched all the observational facts that existed at the time. Hoyle’s blunder was in his apparently pigheaded, almost infuriating refusal to acknowledge the theory’s demise even as it was being smothered by accumulating contradictory evidence, and in his use of asymmetrical criteria of judgment with respect to the big bang and steady state theories. What was it that caused this intransigent behavior? To answer this intriguing question, I started by asking a few of Hoyle’s former students and younger colleagues for their opinions.

  Cosmologist Jayant Narlikar was Hoyle’s graduate student, and he continued to collaborate with him throughout Hoyle’s life. The two researchers developed, among other things, a theory of gravity known as the Hoyle-Narlikar theory, which fits into their quasi–steady state model. Narlikar suggested that Hoyle’s displeasure with the big bang model stemmed, at least initially, from genuine discomfort that Hoyle felt with some of the physical premises of the big bang. For instance, Narlikar recalled, Hoyle pointed out that all the other observed background radiations (optical, X-ray, infrared) were found to be associated with astrophysical objects (stars, active galaxies, and so on), and he saw no reason why the cosmic microwave background would be different and related to a singular event (the big bang). Similarly, around 1956, he thought that stars could somehow produce the energy observed in the cosmic microwave background, if one could find a way to synthesize all the helium in stars. On the more emotional side, Narlikar felt that the fact that Hoyle was not a religious person might have also contributed to his objection to a universe that appeared all at once.

  Astrophysicists Peter Eggleton and John Faulkner were both Hoyle’s research students in the early 1960s (Faulkner is the person farthest right in the front row in figure 22), but I was somewhat surprised to discover that their sentiments were rather different. Eggleton remembered Hoyle as a person who knew everything that was worth knowing in astrophysics at the time and also knew everybody that was anybody in the world of astrophysics. He remarked that a whimsical line that had been used to describe the Victorian scholar Benjamin Jowett could be adopted as a genuine characterization of Hoyle, namely: “What he didn’t know wasn’t knowledge.” Concerning Hoyle’s attitude toward science, Eggleton’s impression was that if the scientific community believed something, Hoyle would be inclined to believe the opposite, to see how far he could go. When I pressed him on why he thought Hoyle was so reluctant to accept the big bang, Eggleton expressed the view that Hoyle’s rejection of the idea that life on Earth emerged through a natural, chemical evolution was at the root of this resistance. Hoyle insisted, Eggleton said, that the origin of life required much more time than the age of the universe as inferred from the big bang theory. This is an interesting point, to which we shall return shortly.

  Faulkner admitted that he himself was puzzled by Hoyle’s unyielding position toward the big bang. In his opinion, Hoyle “went off the rails a bit, having developed a love for his brainchild [the steady state theory] and not wanting to give it up.” He made another interesting comment that by the late 1960s, Hoyle’s interest in what one might call “normative science” decayed, giving way to a more maverick path.

  Martin Rees, Astronomer Royal for Britain, succeeded Hoyle both as Plumian Professor and as director of the Institute of Astronomy at the University of Cambridge. He remembers Hoyle fondly as being always supportive, in spite of the fact that some of Rees’s own work on the cosmic microwave background and on quasars helped bring about the collapse of the steady state theory. Rees still holds Hoyle in the highest regard—a photograph of Hoyle hangs on the wall of Rees’s office at the Institute of Astronomy. Rees offered two tantalizing potential causes for Hoyle’s dissidence. First, he emphasized the negative effects of scientific isolation. He explained that from about the mid-1960s on, Hoyle talked about science almost exclusively with his close collaborators: a very small group that included Jayant Narlikar, Chandra Wickramasinghe, and the Burbidges. Since these scientists rarely if ever disagreed with Hoyle, this was clearly not a good recipe for changing one’s views. To my surprise, Rees told me that even though Hoyle had always been very generous and encouraging, he almost never discussed science with him. In fact, Hoyle did not compare notes about new scientific discoveries with any young cosmologists outside his circle of supporters.

  Rees made a second interesting observation, which was reminiscent of one of Faulkner’s remarks. He noted that in the late stages of their working lives, some scientists lose interest in the routine, incremental advances that normally characterize long stretches of scientific efforts, and they turn their attention to completely new branches of science, sometimes even outside their area of expertise. Rees pointed to Linus Pauling’s almost obsessive preoccupation with vitamin C late in his career as an example of this phenomenon, and he held Hoyle’s misguided endeavors regarding the origin of life on Earth in a similar light.

  There is no doubt that the factors suggested by Rees, Eggleton, and Faulkner played roles in Hoyle’s stubbornness. A few statements made by Hoyle himself provide the best evidence. In Home Is Where the Wind Blows, he wrote the following striking paragraph:

  The problem with the scientific establishment goes back to the small hunting parties of prehistory. It must then have been the case that, for a hunt to be successful, the entire party was needed. With the direction of prey uncertain, as the direction of the correct theory in science is initially uncertain, the party had to make a decision about which way to go, and then they all had to stick to the decision, even if it was merely made at random. The dissident who argued that the correct direction was precisely opposite from the chosen direction had to be thrown out of the group, just as the scientist today who takes a view different from the consensus finds his papers
rejected by journals and his applications for research grants summarily dismissed by state agencies. Life must have been hard in prehistory, for the more a hunting party found no prey in its chosen direction, the more it had to continue in that direction, for to stop and argue would be to create uncertainty and to risk differences of opinion breaking out, with the group then splitting disastrously apart. This is why the first priority among scientists is not to be correct but for everybody to think the same way. It is this perhaps instinctive primitive motivation that creates the establishment.

  One can hardly imagine a stronger advocacy for dissent from mainstream science. Hoyle echoes here the words of the influential second-century physician Galen of Pergamum: “From my very youth I despised the opinion of the multitude and longed for truth and knowledge, believing that there was for man no possession more noble or divine.” However, as Rees has pointed out, isolation has its price. Science progresses not in a straight line from A to B but in a zigzag path shaped by critical reevaluation and fault-finding interaction. The continuous evaluation provided by the scientific establishment that Hoyle so despised is what creates the checks and balances that keep scientists from straying too far in the wrong direction. By imposing upon himself academic isolation, Hoyle denied himself these corrective forces.

  Hoyle’s idiosyncratic ideas on the origin of life had undoubtedly also fueled his refusal to abandon the steady state theory. Here is how Hoyle himself put it:

  The proper philosophical point of view, I believe, for thinking about evolution cosmologically involves issues that are superastronomical, as one inevitably gets as soon as one attempts to understand the origin of biological order. Faced with problems of superastronomical order of complexity, biologists have resorted to fairy tales. This is shown by a consideration of the order of the amino acids in any one of hundreds of enzymes [Hoyle estimated that the probability of forming two thousand enzymes at random from amino acids was about one in 1040,000.] . . . to have any hope of solving the problem of biological origins in a rational way a universe with an essentially unlimited canvas is required [emphasis added], a universe in which the entropy per unit mass [a measure of the disorder] does not increase inexorably, as it does in big bang cosmologies. It is to provide just such an unlimited canvas that the steady-state theory is required, or so it seems to me.

  In other words, Hoyle believed that an evolving universe, with its associated increasing disorder, does not provide the necessary conditions for something as ordered as biology to emerge. He also did not think that the age of the universe, as implied by the value of the Hubble constant, was sufficient for complex molecules to form. I should note that mainstream evolutionary biologists flatly reject this argument. In essence, Hoyle tried to revive the “watchmaker analogy” that characterized all intelligent design arguments by comparing the random origin of a living cell to the likelihood that “a tornado sweeping through a junkyard might assemble a Boeing 747 from the materials therein.” Biologist Richard Dawkins labeled this reasoning “Hoyle’s fallacy,” pointing out that biology does not require intricate life structures to arise in a single step. Organisms that can reproduce themselves are able to generate complexity through successive changes, while inanimate objects are unable to pass on reproductive modifications.

  To progress somewhat beyond these partial explanations for Hoyle’s blunder, especially when it comes to his apparent denial of having made a mistake, we need to understand the concept of denial a little better. Denial seldom evokes sympathy, especially in scientific circles. Justifiably, scientists regard denial as being contradictory to the research spirit, where old theories have to give way to new ones, when experimental results so require. Research, however, is still carried out by humans, and Sigmund Freud himself had already postulated that humans have developed denial as one of their defense mechanisms against traumas or external realities that threaten the ego. We are all familiar, for instance, with denial as the first of the five recognized stages of grief. What is perhaps less widely known is that the experience of being wrong in a major enterprise constitutes such a trauma. The judicial system provides ample evidence that this is indeed the case. There have been quite a few incidents in which both victims of violent crimes and prosecutors in such cases absolutely refused to believe that the person originally found guilty was actually innocent, even after DNA evidence or new testimony exonerated this person conclusively. Denial offers the troubled mind a way to avoid reopening experiences that were thought to have been brought to a successful closure. To be sure, being wrong in a scientific theory cannot be compared with erring in convicting an innocent person, but the experience is traumatic nonetheless, and we may assume that denial, in this sense, may have played a part in Hoyle’s blunder.

  I have noted several times that the idea of a steady state universe was brilliant at the time it was proposed. In retrospect, the steady state universe, with its continuous creation of matter, shares many features with currently fashionable models of an inflationary universe: the conjecture that the cosmos experienced a faster-than-light growth spurt when it was a fraction of a second old. In some respects, the steady state universe is simply a universe in which inflation always occurs. Physicist Alan Guth proposed inflation in 1981 to explain, among other things, the cosmic homogeneity and isotropy. Hoyle enjoyed pointing out that in a paper he had published with Narlikar in 1963, they had shown that their proposed creation field “acts in such a way as to smooth out an initial anisotropy [dependence on direction] or inhomogeneity [departure from uniformity],” and that “it seems that the universe attains the observed regularity irrespective of initial boundary conditions.” These are precisely the properties now attributed to inflation. Hoyle’s brilliance was also revealed in the fact that he belonged to that small group of scientists capable of investigating two mutually inconsistent theories in parallel. In spite of continuing to hold out against the big bang for his entire life, Hoyle actually contributed important studies to big bang nucleosyntheses, in particular concerning the cosmic helium abundance and the synthesis of elements at very high temperatures.

  Lord Rees described Hoyle once as “the most creative and original astrophysicist of his generation.” As a humble astrophysicist, I agree wholeheartedly. Hoyle’s theories, even when eventually proven wrong, were always dynamizing, and they unfailingly energized entire fields and catalyzed new ideas. It’s no wonder that Hoyle’s statue (figure 31) now stands just outside the building named after him at the Institute of Astronomy in Cambridge, which he founded in 1966.

  Figure 31

  As momentous as Hoyle’s contributions have been, there is no question that the person who is most responsible for our current understanding of the workings of the cosmos at large is Albert Einstein. His theories of special and general relativity completely revolutionized our perspective on two of the most basic concepts in existence: space and time. Oddly, the phrase “biggest blunder” has become intimately associated with one of the ideas of this most iconic of all scientists.

  CHAPTER 10

  THE “BIGGEST BLUNDER”

  My subject disperses the galaxies, but it unites the earth.

  May no “cosmical repulsion” intervene to sunder us!

  —SIR ARTHUR EDDINGTON

  When I throw my keys up in the air, they reach some maximum height, and then they fall back into my hand. Only for an instant do the keys stay still, as they reach the highest point. Obviously, the gravitational pull of the Earth is responsible for this behavior. If somehow I could propel the keys to a speed exceeding about seven miles per second, they would escape the Earth altogether, as did, for instance, the Pioneer 10 spacecraft, with which communication was lost in 2003, when the probe was at a distance of more than seven billion miles from Earth. However, in the absence of an opposing force, the Earth’s gravity alone does not allow for the keys to float suspended in midair.

  Two scientists showed independently in the 1920s that the behavior of the cosmic space-time is expected to
be very similar. Those two researchers, Russian mathematician and meteorologist Aleksandr Friedmann and Belgian priest and cosmologist Georges Lemaître, applied Einstein’s theory of general relativity to the universe as a whole. They soon realized that the gravitational attraction of all the matter and radiation in the universe implies that space-time, Einstein’s combination of space and time, can either stretch or contract, but it cannot stably stand still at a fixed extent. These important findings eventually provided the theoretical background for the discovery by Lemaître and Hubble that our universe is expanding. But let’s start from the beginning.

  In 1917 Einstein himself first attempted to understand the evolution of the entire universe in light of his general relativity equations. This effort initiated the transformation of cosmological problems from speculative philosophy into physics. The expansion of the universe had not been discovered yet. Moreover, not only was Einstein unaware of any observed large-scale motions, but until that time, most astronomers still believed that the universe consisted exclusively of our Milky Way galaxy, with nothing beyond. Astronomer Vesto Slipher’s observations of the redshifts (the stretchings of light, which were later interpreted as recession velocities of galaxies) of “nebulae” were neither widely known nor understood at the time. Astronomer Heber Curtis did present some preliminary evidence that the Andromeda galaxy, M31, might be outside the Milky Way, but Edwin Hubble confirmed unambiguously this profound fact—that our galaxy is not the entire universe—only in 1924.

 

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