Brief history of time.

`A brief history of time' by Stephen Hawking, Bantam Books, 1988

In the clear frosty predawn of 17 November I was watching the Leonid meteor shower. Not far away a tawny owl was calling. Pieces of comet debris blazing trails through the earth's atmosphere, and a hunter able to catch mice in near darkness--wonders of physics and biology.

Two celebrated books attempt to explain for the layman how such fascinating phenomena as the universe and owls have come into being. They are Stephen Hawking's A brief history of time and The selfish gene by Richard Dawkins. Both are readable, though not necessarily easy to comprehend; both have something of the feel of a detective yarn as logic and intuition, tested where possible by experiment, unravel varied mysteries of life and the universe.

The framework of a scientific explanation of how lifeforms such as owls evolved was, of course, put forward in 1859 when Charles Darwin published The origin of species.

Darwinism says that the tawny owl's ability to survive by hunting at night in temperate woodland has evolved through natural selection. Ancestral owls hunting in low levels of light relied on keen hearing, good night vision, sharp talons and silent flight. Those individuals which possessed these attributes to the greatest degree were most likely to survive to breed, thereby passing them on to the next generation. Over the millennia this produced the tawny owl, superbly adapted to exploit its particular ecological niche.

The selfish gene, which first appeared in 1976, popularized a new approach. Dawkins explains evolution not from the perspective of individual living entities but from that of the gene, which he defines as `any portion of chromosomal material that potentially lasts for enough generations to serve as a unit of natural selection'. It is a living entity's genes that determine its physical characteristics and instinctive behaviour.

The essence of Dawkins' thesis is that natural selection is all about individual genes competing for survival, which in practice means reappearing in as many individuals as possible. Of course genes do not compete in a conscious way, they merely survive better on average than rival genes because of the qualities with which they endow their owner bodies.

Dawkins expresses some surprising ideas, which is one reason his book is so compelling. We do not own our genes, he suggests, we are their `survival machines'. In effect, evolution is gene-driven. He even goes so far as to surmise that our bodies might be an extreme form of symbiosis. Just as there are certain pairs of life-forms that depend on each other for their mutual survival, our bodies are a complex mass of mutually dependent genes. Dawkins' basic thesis is now common currency: its language is often used in TV wildlife films as if it were incontrovertible fact.

His stated purpose in writing is `to examine the biology of selfishness and altruism'. He sets out to justify his theory in the face of instances in nature where animals act in apparently altruistic ways--such as `stotting', the extraordinary high leaping performed by Thomson's gazelles when they try to evade a predator. This might be interpreted as one individual unselfishly reducing its chance of escape in order to warn its fellows of the danger. But Dawkins makes a plausible case that this gene-determined behaviour could lead to a greater chance of survival.

Interestingly, Dawkins, a convinced atheist, seems to accept original sin. Mankind, of all living creatures, is able to rebel against `the tyranny' of self-replicating genes. `Be warned,' he writes, `that if you wish, as I do, to build a society in which individuals cooperate generously and unselfishly towards a common good, you can expect little help from biological nature. Let us try to teach generosity and altruism, because we are born selfish. Let us understand what our own selfish genes are up to, because we may then at least have the chance to upset their designs, something that no other species has ever aspired to.'

In A brief history of time, Hawking gives a masterly survey of the main developments in cosmology. He discusses the emergence of the various theories, and the problems that led to the rejection of some and the development of others.

For example, the fact that the speed of light appears the same to all observers, however they are moving in relation to each other, spiked the belief that a universal `ether' transmitted light waves. Einstein's special theory of relativity takes account of this--and leads to some conceptually difficult conclusions. One is that the mass of an object will increase as it travels faster relative to an observer; yet an observer moving with that object will detect no change in its mass.

Some theories, such as Einstein's, have relevance on a galactic scale; others, such as quantum mechanics and Heisenberg's Uncertainty Principle, initially appear relevant only in the subatomic realm.

Then, invoking both sets of theories, Hawking looks at attempts to explain phenomena such as black holes (celestial bodies of such high mass that light cannot escape their gravitational fields). This leads on to a quantum theory of gravity. He draws the reader along the mind-boggling route whose ultimate goal, he is convinced, will be a unified theory of physics. This will account for, in one theorem, the four fundamental forces of nature: gravity, electromagnetism, nuclear weak and nuclear strong. To survey this abstruse subject with the use of only one mathematical formula, and even to inject some humour along the way, is a remarkable achievement.

Dawkins dismisses the idea of a Creator: chance and natural selection can account for everything that is living and the phenomenon of life itself. Hawking side-steps the issue: if space-time is a self-contained continuum without boundaries, as the quantum theory of gravity implies, it is meaningless to talk about what happened at or before its origin (which would be a boundary).

But neither book deals convincingly with other fundamental questions. Who or what determined the `laws' of physics and evolution? Who set the physical values (such as the strength of the gravitational force) that dictate the nature of the universe? Does life really have no other purpose than its own perpetuation?

Such questions enter the realm of philosophy and theology and go beyond science. Hawking's agnostic tone (in this book at least) is arguably the more scientific: one senses that his mind is not closed to the possibility of a creator God. In fact he makes the unlikely suggestion that the day may come when everyone understands the `complete' theory. `Then we shall all ... be able to take part in the discussion of the question of why it is that we and the universe exist. If we find the answer to that, it would be the ultimate triumph of human reason--for then we would know the mind of God.' But does not God operate in a realm beyond human reason?

Dawkins' work, it seems to me, has more relevance to how we live in this amazing universe. Whatever our religious convictions, it is vital that we grapple with his challenge that selfishness need not be the decisive motive.