Hawking and other forms of hunting

A recent best-seller illustrates the history of the triumph of intellectual theory over ignorant pragmatism or reactionary ideology.

I was at a dinner-party recently where a guest was enthusing over the remarkable abilities of his 82-year old father. The old man had been expounding the virtues of Hawking and it had taken some time for my friend to realize that his father was not advocating some esoteric form of hunting. Instead he was talking about cosmology and how his interest had been awakened by Stephen Hawking's book A Brief History of Time. 1 have long been fascinated by cosmology but until Hawking came along it tended to be something of a conversation stopper at your average dinner party.

Hawking's literary success has been remarkable to say the least.

He spent thirty-two weeks at the top of the English Booksellers' best-seller list. There is wonderful irony in that A Brief History of Time, in which Hawking almost asks for a heretical banning, which did not eventuate, was finally toppled by Rushdie's Satanic Verses—which didn't and got it. We can presume that Hawking will be doubly aware of this irony as he was born three hundred years to the day after Galileo, the first famous heretic of modern science.

In his book Hawking tells us how the Pope, in an audience, had advised Hawking, and fellow participants in a Jesuit-organised conference on cosmology, that it was all tight for science to study the evolution of the universe after the Big Bang but that it should not enquire into the Big Bang itself because that was the moment of Creation and therefore the work of God.

The Pope was not to know that Hawking was at that time developing his theory that while space-time is finite it has no boundary which means that it has no moment of creation.

Although beautifully and elegantly written, the book is no light-weight. We are introduced to the key concepts of modern physics including special and general relativity, the expanding universe, the uncertainty principle, and black holes, along with the complexities of broken symmetry, quark theory, strings, and Grand Unification Theories.

Valley of the Dolls it is not.

I believe that Hawking has struck a popular chord with his readers in that he has made his name as an arm-chair theoretician rather than as a technician playing with millions of dollars worth of equipment. The early "natural philosophers" such as Aristotle were also arm-chair theoreticians who simply thought about the world and developed their theories in comfort and elegance—or occasionally from inside a barrel.

Then came Galileo who overturned so many previous theories with the use of his telescopes and rolling cannon balls.

From that day science has been inescapably linked with experiment to the point where most school texts have encouraged the belief that scientific theories are built up or deduced from experimental activity. It took Karl Popper to remind us that observation and experiment can only test theories and that the great theories are acts of pure creation—more akin to music and art than to engineering or the practise of technology.

But in the meantime the world of science was seen as being entrenched in the environment of the laboratory and too busy asking what the universe is to ask the question why. On the other hand the philosophers have not been able to keep up with the advance of science, especially during the nineteenth and twentieth centuries, as science appeared to be too technical and mathematical for anyone to make a contribution except a few specialists working within their own esoteric fields. Hawking argues that if we can discover a truly complete theory of the universe it should, in time, be understandable by everyone. His hope is that then we shall all be able to take part in the discussion of why it is that we and the universe exist. As he puts it, "To know the answer to that is to know the mind of God".

I am sure that part of Hawking's appeal is that he holds out this hope and promise to the reader on every page. We are curious. We want to know. Hawking's grand plan makes the hard bits worth the effort.

But was it true that during the nineteenth and twentieth centuries the armchair theorist had no means of contributing to the advancement of science? Hawking drops a few hints that it was not. John Gribbin, the other great science writer of our time, makes no bones about it.

In In Search of the Big Bang and to a lesser extent in In Search of Schrodinger' s Cat Gribbin argues that it was the experimenters who held up the advancement of science because of their refusal to take the theories of the "handwavers" seriously. To be fair, Gribbin acknowledges that the hand-wavers were so entrenched in the mechanistic view of science that all too often they too failed to accept their own theories as being serious models of the real world—especially when, as with relativity and quantum physics, these theories described a world more curious than could readily be imagined at the time.

To test this idea let's carry out a thought experiment of our own.

Imagine you are sitting outside your cottage in New Zealand around 1905 drinking tea and pondering the mysteries of the night sky. As a reasonably well-informed person of the time you would be aware of the debates of the time regarding the size of the universe. How far is up? The question to be answered was whether the universe ended at the boundaries of our own Milky Way or was there more beyond?

As you rested from your sky-gazing to stir some milk into your tea you would notice the tea rising up the rim.

Any text of the time would explain that Newton in 1686 had recognized that this "centrifugal effect" showed that the tea in the cup somehow knows that it is rotating in its own "inertial frame". The puzzle was what constituted the inertial frame?

A few years later Berkeley pointed out that it is because the tea rotates relative to the distant stars that it rises up the sides of the cup in protest. (It is not the motion relative to the cup. Try putting your cup in the middle of a revolving turn-table. The tea will still rise.)

In 1700 Kant became aware of the work of Wright which argued that our own galaxy was not a sphere but was disc-like, as evidenced by the appearance of the Milky Way. Kant then concluded that as our own galaxy was a rotating flattened disc there might be many more like it in the universe. Had he pondered his stirred tea he might have further realized that, just like the tea, our own Milky Way can only know it is rotating by reference to a host of other remote galaxies.

We would then have had a few hundred years to get used to the idea that the Milky Way is only one of many galaxies in the universe.

Let us imagine then, that given the benefit of the New Zealand solitude, you have once again come to this conclusion that our galaxy is but one of many and that the universe is truly huge. This remarkable outcome might encourage you to consider the other great puzzle of the time—why is the night sky dark?

Around the turn of the century it was generally believed that the universe was filled with stars, was infinite in time and space, and was eternal and unchanging. But several philosophers had recognized that if this were so then wherever we looked into the night sky we should finally light upon a star and that the whole sky should be as bright as the surface of the sun's own disc.

The obvious and wrong response is that as the stars get further away they become less bright. It is true that their brightness diminishes as the square of their distance but the number of stars which can occupy the same "'stellar sphere" increases by the same ratio—hence the two factors cancel each other out. My school texts explained the puzzle away by claiming that the light from distant stars is blocked from reaching us by inter-stellar dust and the like. Also wrong. In time the dust would absorb the energy, heat up and re-radiate it. The answer lies in one of the properties of light itself—it travels at a finite speed. The fact that light has a finite speed had been well established by 1700 so this should be no surprise to you sitting outside your Kiwi cottage around 1905. Hence you might decide that the reason the sky is not full of light is that the universe is not eternal and unchanging but is quite young and that there simply has not been time for the stars to fill the sky with light.

You might even have concluded that if the universe had a recent beginning it might also be expanding rapidly with the result that much of the light from the most distant stars might be red-shifted out of existence. An expanding universe would also overcome another problem which Newton himself identified. Why does gravitational attraction not cause all the stars to fall back into some central place?

Within the confines of this column I cannot explain all the arguments that could lead you to these startling conclusions but the knowledge and theories were all there at the time. If you had held your conclusions with sufficient confidence you might just have written a letter to a clerk in a patent office in Switzerland who had just published his Special Theory of Relativity.

Your letter might have read: "Dear Albert, I wish to advise that the universe is huge and filled with many galaxies beyond the Milky Way, that it is certainly not static and unchanging, but is quite recent in origin and might even be expanding."

Einstein might just have torn up such a message from the colonies. But had he taken it to heart you might have earned a Nobel Prize. When Einstein first developed his General Theory of Relativity in 1915 the popular scientific consensus was that we inhabited a static universe defined by the Milky Way. When Einstein ran the equations describing such a universe through the appropriate manipulations of General Relativity the equations said that the universe must be contracting or expanding but that it could not stand still. The only way to hold the system still and to mimic a universe extending no further than the Milky Way was to add an extra term to the equations which he called the "cosmological constant". He later called this the greatest blunder of his life.

Einstein's own equations had been trying to tell him the truth. Your letter might have arrived in time to encourage him to believe them—and you would have changed the course of history.

But theory had run ahead of the observations and in the spirit of the times the observers had to set the pace.

You could have made your contribution with experimental equipment consisting of no more than a tea-cup and a comfortable chair.

This is the world of science that Hawking brings back to us. Furthermore, Hawking personally encapsulates the promise of the natural philosopher because he is a victim of ALS, a motor neuron disease which has rendered him immobile and speechless. He can only communicate through computer aids and a speech synthesizer.

He believes, and others comment, that it is precisely because he is so detached from the physical world that his mind is able to make the great conceptual leaps which characterize his theories.

He has purified the concept of pure thought and at the same time demonstrated its power. Hence, he reinforces our humanity in an age which has too often seemed set on rendering us subservient to the machine.

Many who have read A Brief History of Time may not fully grasp the cosmology and the underlying physics, but I am sure that anyone who reads even part of it will gain a new confidence in the culture of the twentieth century. It is certainly a relief from Sartre, Camus, Brecht and the rest. Q