When Reason in Revolt was published seven years ago, it was greeted with enthusiasm by many people, not just by Marxists but those who were interested in the new scientific theories of chaos and complexity. But some readers found the authors' opposition to the theory of the Big Bang hard to accept, after all it seemed that the whole scientific community accepted the theory without question. But last week Paul Steinhardt and Neil Turok published a paper in Science in which they propose an alternative model to the Big Bang theory. They suggest that the universe goes through and endless cycle of big bangs, expansion and then stagnation. Their ideas are at an early stage but they are clearly a step forward from the mystical idea that the universe was created out of nothing.

The publication of Reason in Revolt seven years ago was greeted with enthusiasm by many people, not only on the left, but by scientists and other people interested in philosophy and the latest scientific theories, such as chaos and complexity, which in many respects reflect a dialectical approach to nature.

The latest discoveries of palaeontology, in particular the pioneering work of Stephen J Gould (punctuated equilibria) have fundamentally modified the old view of evolution as a slow, gradual process, uninterrupted by sudden catastrophes and leaps. Gould himself has paid tribute to the contribution of Engels, who, in his little masterpiece The Part Played by Labour in the Transition from Ape to Man, brilliantly anticipated the latest discoveries in the investigation of human origins.

Since the book first appeared, there have been a number of other spectacular advances in science - notably the human genome. These results have completely demolished the positions of genetic determinism that we criticised in Reason in Revolt. They have also dealt a mortal blow to the nonsense of the Creationists who want to reject Darwinism in favour of the first chapters of Genesis. It has cut the ground from under the feet of the racists who attempted to enlist the service of genetics to peddle their reactionary pseudo-scientific "theories".

However, there was one part of Reason in Revolt that some found rather hard to digest - namely the section on cosmology, where we argued against the theory of the Big Bang. The standard model of the universe seemed to be so entrenched that it was apparently unassailable. The overwhelming majority accepted it uncritically. To call it into question was almost as unthinkable as the Pope in Rome questioning the Immaculate Conception.

The Big Bang theory was an attempt to explain the history of the universe on the basis of certain observed phenomena, in particular the fact that we can see the galaxies receding from each other. Because of this, most astronomers believe that these star groupings were closer together in the past. If we run the film backwards then all matter, space and time would have erupted from a point in a massive explosion, involving staggering amounts of energy.

In the most widely accepted cosmological model, called the inflationary model, the universe was born in an instantaneous creation of matter and energy. It is the modern equivalent of the old religious dogma of the creation of the world from nothing. The Big Bang is alleged to be the beginning of space, matter and time. As the universe has inflated since that event, matter and energy have spread out in clumps. The spreading could potentially continue forever.

This model has gained widespread acceptance because it accounts for several important features we see in the universe - such as why everything looks the same in all directions and the fact that the cosmos appears "flat" (parallel lines would never meet however long).

"The inflation idea has been tremendously influential," notes Robert P. Kirshner, an astrophysicist at Harvard University. "No observation's been found that proves it wrong." But, he added, "that does not, of course, mean that it's right." (National Geographic News, April 25, 2002)

In fact, there are serious problems with this theory, which we outlined in detail in Reason in Revolt. In particular, questions about what happened "before" the Big Bang cannot really be asked because there is supposed to have been "no before" - since there was no time. In this way, an absolute limitation is placed on the possibility of our understanding the universe, thus leaving the door wide open for all kinds of mystical ideas - which have been pouring out in vast quantities in recent years. Nevertheless, the inflationary theory has survived since it was introduced in the late 1970s, while cosmologists have discarded competing ideas one by one.

However, new problems with the existing theory were becoming apparent all the time. The latest was in 1998, when studies of distant, exploding stars showed the universe was expanding at an accelerating rate. This was a big surprise, since most researchers believed that either the universe would expand forever at the same rate or else slow down and contract, eventually coming back together in a "Big Crunch".

In the last week, a report by Paul J. Steinhardt and his colleague Neil Turok of Cambridge University posted on April 25 on the website of the prestigious journal Science, has thrown down a serious challenge to the accepted wisdom. The two scientists have put forward a new model to explain how the cosmos is and where it might be going. They argue - as we did in Reason in Revolt - that the universe had no beginning and it will have no end.

Steinhardt and Turok point out that the standard model has several shortcomings. It cannot tell us what happened before the Big Bang or explain the eventual fate of the universe. Will it expand forever or stop and contract? These were some of the objections we raised in Reason in Revolt.

They propose that the cosmos goes through an endless cycle - of Big Bang, expansion and stagnation - driven by (an as yet unexplained) "dark energy". They argue that it is necessary to take account of recent discoveries that have surprised the scientific community - such as the observation that everything in the universe is moving apart at an accelerating rate. The apparent acceleration has since been checked and shown to be real. The standard model certainly did not predict such features!

To explain this, astronomers invoked an old idea that space contains a so-called dark energy that is pushing the galaxies apart. Steinhardt and Turok have put this energy - a scalar field as they mathematically describe it - at the centre of their new model. They think the dark energy drives a cycle of activity that includes a big bang and a subsequent period of expansion that leaves the universe smooth, empty and flat.

The new model offers a streamlined alternative to the standard model. It treats the big bang not as the moment of creation, but as a transition between two cycles in an endless process of cosmological rebirth. According to the model, the big bang is followed by a period of slow expansion and gradual accumulation of dark energy. As dark energy becomes dominant, it stimulates cosmic acceleration. The current era is near the transition between these stages, the authors maintain.

At present, they argue, the universe is in an expansionary phase, and the current expansion will go on for trillions of years, before reaching a critical point where the process takes a new direction. Although there are many questions still to be answered (in particular the question of this hypothetical "dark energy"), the new model seems to be a vast improvement on the existing one, which states that the Big Bang was the beginning of time, matter, space and energy - clearly a mystical and unscientific conception. The new theory does away with the idea that the universe has either a beginning or an end - it is infinite in both time and space.

Steinhardt adds: "In the standard picture, it's presumed that the Big Bang is actually a beginning of space and time; that there was nothingness, and then suddenly out of nothingness there sprang space, time, matter, radiation, etc."

Although the standard model has proved difficult to dislodge, many scientists were already becoming troubled about its contradictions and inconsistencies. According to Steinhardt, the new theory "predicts all the features of the standard model, using fewer ingredients." In fact, several features of the cosmos can be better explained by the cyclic model, including the geometry of the universe, its overall uniformity, and in particular, the existence of acceleration. The authors of the report have discussed their ideas with other scientists and have received a positive, but "cautious", response.

The new model is yet another example of the dialectical law of the transformation of quantity into quality. "The scalar field changes its character over time," Paul Steinhardt told the BBC. "Finally, the field begins to build up energy to a point where it suddenly becomes unstable and bursts into matter and radiation, filling the universe, and driving the next period of expansion."

We are dealing here with unimaginably vast periods of time. As accelerated expansion proceeds over trillions of years, matter and energy are gradually stretched thin across the universe. Eventually, matter, radiation, and even black holes become so stretched out that they are dissipated to almost nothing, leaving behind a massive universe that is virtually empty.

"At this point in the cycle, particles of matter are so far apart - and moving away from each other so rapidly - that they cannot interact and are effectively separated into distinct universes. Steinhardt and Turok call this vacuum-like stage the "big crunch". The vacuum triggers dark energy to materialize into matter and radiation in another Big Bang, refreshing the cycle of expansion." (National Geographic News, April 25, 2002)

This model puts an end to the nonsense of the creation of the universe from nothing:

"What we're proposing in this new picture is that the Big Bang is not a beginning of time but really just the latest in an infinite series of cycles, in which the universe has gone through periods of heating, expanding, cooling, stagnating, emptying, and then re-expanding again." (BBC report)

The picture of the universe presented here is one that is entirely consistent with the theories of dialectical materialism, which state that the universe is infinite, eternal, and ever changing. This does not at all preclude the possibility of a big bang. Indeed, we have already argued that there have probably been many big bangs. But what it certainly does preclude is any question of matter (or energy, which is exactly the same thing) can be created out of nothing (as the Big Bang theory implies) or destroyed.

It is, of course, extraordinarily difficult to solve the kind of problems posed by an infinite universe. Cosmology writer Marcus Chown concedes it will be extremely difficult to finally prove any model of the universe. He is refreshingly honest about the problems involved: "The history of cosmology is the history of us being completely wrong," he told the BBC. "I mean, cosmology is the hardest of all sciences; we sit on this tiny planet in the middle of this vast universe, we can't go anywhere and do any experiments - all we can do is pick up the light that happens to fall on us and deduce some things about the universe."

Yet despite this, scientists continue to probe the secrets of the universe and nature, wresting one result after another. The whole history of science is the history of humanity's advance from ignorance to knowledge, from error to the truth. This is itself a dialectical process, where each generation arrives at a theory that explains many things. But at a certain point, small irregularities are found that contradict the accepted model. This eventually leads to its overthrow and replacement by a new model, which will itself eventually be surpassed.

In this way, human knowledge penetrates deeper and deeper into the secrets of the universe. And this process is never-ending. The day will never dawn when humanity will be able to say: "We now understand everything." The universe is infinite, and so is the process of human understanding, which inevitably proceeds through a whole series of errors, or, more correctly, partial truths.

The new theory must, of course, be demonstrated through observation. There are ways in which this can be done. For example, gravitational waves, a feature of the universe predicted by general relativity, would take a different form in these two models. There would not be long-wavelength gravitational waves in a cyclic universe, whereas there would be in an inflationary universe.

Thus, measurements of gravitational waves and the properties of "dark energy" can provide decisive ways to discriminate between the two pictures observationally. Efforts are underway to measure and characterise gravitational waves, but it will likely take at least several years to gather useful data. The Planck satellite, which is scheduled to be launched by the European Space Agency around 2008 may help settle the question.

It is too early to say whether it will be verified in detail. However, what is clear is that the deficiencies of the Big Bang theory are now becoming clear, and the search is on for an alternative. Whether or not the present theory is correct in its detail, the method that its authors have used - a materialist and dialectical method - is obviously correct. And, as they correctly write in Science: "The ultimate arbiter will be Nature."