The Guardian January 23, 2003

Universal truths

by Paul Davies

In a famous conclusion to his popular cosmology book The First Three Minutes, the physicist Steven Weinberg wrote: "The more the universe appears comprehensible, the more it also appears pointless." This comment echoes the sentiment of many contemporary scientists. Although they may wax lyrical about the awesome beauty, majesty and subtlety of the natural world, they nevertheless deny any point or purpose to the universe.

A hundred years ago, the mathematician and philosopher Bertrand Russell used the second law of thermodynamics in a trenchant attack on theism. The second law states, in effect, that the universe is dying, descending inexorably into chaos as its reserves of useful energy are squandered. Russell reflected on the "vast death of the solar system" that will follow when the sun burns out in several billion years' time.

Russell's position seems to be that if the universe is doomed, then physical existence is ultimately pointless; even human life and endeavour is futile. In recent years, the chemist Peter Atkins has developed this theme by tying the second law directly to the purposeless motion of molecules. It is the random agitation of molecules that drives, say, a gas to states of higher and higher entropy, culminating in a state of thermodynamic equilibrium and effective macroscopic inactivity. Atkins elevates this indisputable fact about molecular motion to the status of a universal principle of purposelessness, in which the aimless meanderings of molecules become emblematic of the pointlessness of the universe.

This argument assumes that entropy alone is an appropriate indicator of cosmic change. The decision to focus on this quantity is a purely ideological one. Russell and Atkins select entropy as the physical property for discussion because it paints a bleak picture of a degenerating, indeed doomed, universe. But there are other ways to describe cosmic evolution.

There is good astronomical evidence that the universe began in a state of almost total blandness. The richness and diversity of physical systems we observe today have emerged through a long and complicated series of self-organising and self-complexifying processes. Viewed this way, the conspicuous story of the universe so far is one of unfolding enrichment, not decay. There is nothing within science as such to compel one to favour entropy over organised complexity in characterising the evolution of the universe.

Second, it is obviously wrong to claim that a system with a finite life span cannot have a point. Individual human lives and cultures are subject to the same strictures of the second law of thermodynamics, and are finite as a result. Yet human beings and society have all sorts of goals and purposes. To say there is no point to human life because we each will one day die is clearly ridiculous. So the fact that the stars may not burn forever, or the entire universe may eventually approach a state of thermodynamic equilibrium (or even dark emptiness) has little bearing on whether or not the universe has a point.

Biologists have used the supposed lack of directionality in physical processes in support of a philosophical position similar to Weinberg's. Stephen Jay Gould liked to attack the Victorian notion of evolutionary progress. He stresses that nature is blind, and so cannot look ahead to anticipate solutions to evolutionary problems. Darwinism is based on purely random accidental changes; some good, some bad. Gould says evolution is not going anywhere, it is just exploring the vast space of biological possibilities. He concludes that if evolution is blind, the universe as a whole must be pointless.

The evidence for the directionlessness of biological evolution is scientifically less compelling than is the case for the second law of thermodynamics. Taking the biosphere as a whole, its complexity has clearly risen since life on Earth was restricted to a few microbes. The issue, however, is whether this merely represents an undirected meandering through random biological structures, or whether there is a systematic trend toward greater complexity.

The fossil record is ambiguous. Certainly some trends are discernible; the ratio of brain mass to body mass escalated persistently during hominid evolution. Some contemporary biologists, such as Simon Conway Morris of Cambridge University, make a case that, at least within certain lineages, there are trends towards greater complexity. So it is far from decided, even among professional biologists, that the evolutionary record supports a doctrine of biological chaos.

Recently, some cosmologists have attempted a catch-all argument for cosmic pointlessness by invoking the multiverse concept. This is based on the theory that our universe is but a small component in a vast assemblage of universes. The universes may co-exist in parallel, so that they are physically disconnected, or they may connect to each other in remote regions of space or through "wormholes". Universes may differ in both their physical laws and initial conditions, in such a way that all conceivable laws and conditions are represented in a universe somewhere. The overwhelming majority of the universes would go unseen because their laws and conditions would not be conducive to the emergence of life and conscious beings. Only in a tiny subset where, purely by chance, things fell out just right, would observers arise to marvel over the ingeniously contrived appearance of their universe.

The relevance of the multiverse to cosmic pointlessness is easily grasped. If anyone should discover some aspect of nature that hinted at a deep underlying purpose, then this superficially amazing fact could be shrugged aside as a random accident that is observed by us only because that very same accident is a necessary prerequisite for the existence of life. There are many peculiar aspects of the laws of nature that, had they been slightly different, would have precluded the existence of life.

The multiverse explanation for the apparently contrived ingenuity of the universe suffers from a number of problems. In most versions, the existence of the other universes cannot be verified or falsified, so its status as a scientific theory is questionable. Second, if the bio-friendliness of the natural world were the result of randomness, we might expect the observed universe to be minimally rather than optimally bio-friendly. But the degree of bio-friendliness we observe in the universe is far in excess of what is needed to give rise to a few observers to act as cosmic selectors.

Cosmic pointlessness has also been argued on philosophical grounds on the basis that the very concept of a "point" or "purpose" cannot be applied to a system like the universe because it makes sense only in the context of human activity. Some years ago, I took part in a BBC television debate with Hugh Montefiore, then Bishop of Birmingham, and the atheist Oxford philosopher AJ Ayer. Montefiore declared that without God all human life would be meaningless. Ayer countered that humans alone imbue their lives with meaning. "But then life would have no ultimate meaning," objected the bishop. "I don't know what ultimate meaning means!" cried Ayer. His objection, of course, is that such concepts as meaning, purpose and having a point are human categories that make good sense in the context of human society, but are, at best, metaphors when applied to non-living systems.

However, scientists have long been guilty of projecting on to nature categories that are rooted in human society. The Greeks built a cosmological scheme based on musical harmony and geometrical regularities, because musical and geometrical instruments were the current technological marvels. Newton's universe was a gigantic clockwork mechanism. Russell's was an imperfect heat engine - a sort of Victorian industrial contraption writ large and running out of fuel.

Today, it is fashionable to describe the universe as a gigantic computer. Information theory, which stems from the realm of human discourse, is routinely applied to physical problems in thermodynamics, biology and quantum mechanics. All these designations capture in some imperfect way what the universe is about. It is not a clockwork mechanism or an information processor, but it does have mechanistic and informational properties. Living organisms have goals and purposes, and I see no reason why we may not use the organism as a metaphor for the universe, as did Aristotle two-and-a-half millennia ago.

I am not suggesting that the universe is alive, only that it may share with living organisms certain properties in the same way a machine has interlocking parts, a finite fuel supply, etc. So I contend that the universe may have purpose-like or point-like properties, alongside mechanistic and computational properties.

The universe is ordered in a meaningful way, and scientists seek reasons for why things are the way they are. If the universe as a whole is pointless, then it exists without reason. In other words, it is ultimately arbitrary and absurd. We are then invited to contemplate a state of affairs in which all scientific chains of reasoning are grounded in absurdity. The order of the world would have no foundation and its breathtaking rationality would have to spring, miraculously, from absurdity.

So Weinberg's dictum is turned neatly on its head: the more the universe seems pointless, the more it also seems incomprehensible.

· Paul Davies is at the Australian Centre for Astrobiology at Macquarie University. His latest book is How to Build a Time Machine. He delivers his Michael Faraday Prize lecture, The Origin of Life, at The Royal Society on January 27

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File Date: 01.23.03