Cosmology in Crisis Over Dark Energy
Ten years ago, cosmologists invented dark energy to explain certain features of the expansion of the universe that could not be reconciled with observations of supernova magnitudes. Now, reported National Geographic News, dark energy remains the most profound problem in physics. It’s like theory and observations are refusing to cooperate with an arranged marriage.
Part of the problem has been the inability to unify the mathematics of quantum theory with the equations of general relativity. But then Nature News added this bombshell: the theory of quantum mechanics, which has dominated physics since the 1930s, might be wrong – at least the Copenhagen Interpretation of QM, which leads to paradoxes that have long made physicists uncomfortable.
We have here a strange situation in science. Leading cosmologists have been willing for a decade now to posit an imponderable substance, dark energy, to preserve favored theories of physics and views of the large scale structure of the universe. Even more astonishing, they have been telling the world that this mysterious unknown stuff constitutes 74% of reality. In addition, they have lived with the paradoxes of the Copenhagen Interpretation of Quantum Mechanics for decades – a position that allows for instantaneous action at a distance and for objects to occupy two incompatible states simultaneously. Are they dabbling in the occult or really getting a grip on the universe?
Perhaps someday they will come up with an acceptable solution for the paradoxes of quantum mechanics, and figure out what dark energy is. If so, they will be hailed as visionaries who predicted the nature of reality then found it. If not, future scientists will look back at this period and wonder how brilliant thinkers could have clung to occult forces and unobservable substances for so long. Today’s science could be regarded as tomorrow’s alchemy.
There is a view of science that doubts man’s ability to comprehend reality as it is. The job of science, many have argued, is to organize experience to give us a degree of explanation, prediction and control – not to comprehend reality. This is a pragmatic view. If by using the equations of quantum mechanics we can make lasers and Geiger counters and cell phones, and explain why a spectrum has broad emission lines, that’s all fine and good. It may have nothing to do with reality. Why? Because there is no way we can get outside of our experience to compare our theories with reality and see if there is a good fit. A corollary is that scientific knowledge is never universal, timeless, necessary and certain. It is only tentative. It is the best we can do for now. The best theory, though, is not ipso facto a good theory (see best-in-field fallacy).
We know from history that civilizations have had views of nature that we consider wrong, but those views at the time gave them useful degrees of explanation, prediction and control. In fact, the whole industrial revolution in Western civilization proceeded on ideas about the earth, the universe, the atom and the mind that modern scientists long ago discarded or overhauled completely. Who could know what revolutions are coming that will render today’s best scientific concepts as hopelessly inadequate?
The tension between observation and theory in today’s cosmology underscores the tentative and historical nature of scientific knowledge. We should not view science as necessarily progressing toward the truth. Often, it is more the work of blind men striving to understand the elephant. Just when they think they have the trunk understood, the tusk presents itself as an anomaly difficult to reconcile with theory.
A few smart blind men might be able to put all the parts of one elephant together into an acceptable theory. The universe is far too vast for such a program. There is plenty of space in isolated pockets of the universe for sentient beings to do some work that might prove temporarily useful while such beings are completely out of touch with reality. Dark matter and dark energy at the moment have all the attributes of occult phenomena. We will have to wait and see whether dark energy becomes a truly productive hypothesis or joins the scrap heap of phlogiston, caloric, spider eyes, bat wings and rubber chickens.