What is exploration?

We are all explorers. Our desire to discover, and then share that new-found knowledge, is part of what makes us human - indeed, this has played an important part in our success as a species. Long before the first caveman slumped down beside the fire and grunted news that there were plenty of wildebeest over yonder, our ancestors had learnt the value of sending out scouts to investigate the unknown. This questing nature of ours undoubtedly helped our species spread around the globe, just as it nowadays no doubt helps the last nomadic Penan maintain their existence in the depleted forests of Borneo, and a visitor negotiate the subways of New York.

Over the years, we've come to think of explorers as a peculiar breed - different from the rest of us, different from those of us who are merely 'well travelled', even; and perhaps there is a type of person more suited to seeking out the new, a type of caveman more inclined to risk venturing out. That, however, doesn't take away from the fact that we all have this enquiring instinct, even today; and that in all sorts of professions - whether artist, marine biologist or astronomer - borders of the unknown are being tested each day.

Thomas Hardy set some of his novels in Egdon Heath, a fictional area of uncultivated land, and used the landscape to suggest the desires and fears of his characters. He is delving into matters we all recognise because they are common to humanity. This is surely an act of exploration, and into a world as remote as the author chooses. Explorer and travel writer Peter Fleming talks of the moment when the explorer returns to the existence he has left behind with his loved ones. The traveller 'who has for weeks or months seen himself only as a puny and irrelevant alien crawling laboriously over a country in which he has no roots and no background, suddenly encounters his other self, a relatively solid figure, with a place in the minds of certain people'.

In this book about the exploration of the earth's surface, I have confined myself to those whose travels were real and who also aimed at more than personal discovery. But that still left me with another problem: the word 'explorer' has become associated with a past era. We think back to a golden age, as if exploration peaked somehow in the 19th century - as if the process of discovery is now on the decline, though the truth is that we have named only one and a half million of this planet's species, and there may be more than 10 million - and that's not including bacteria. We have studied only 5 percent of the species we know. We have scarcely mapped the ocean floors, and know even less about ourselves; we fully understand the workings of only 10 per cent of our brains.

Here is how some of today's 'explorers' define the word. Ran Fiennes, dubbed the 'greatest living explorer', said, 'An explorer is someone who has done something that no human has done before - and also done something scientifically useful.' Chris Bonington, a leading mountaineer, felt exploration was to be found in the act of physically touching the unknown: "You have to have gone somewhere new. Then Robin Hanbury-Tenison, a campaigner on behalf of remote so-called "tribal' peoples, said, "A traveller simply records information about some far-off world, and reports back; but an explorer changes the world.' Wilfred Thesiger, who crossed Arabia's Empty Quarter in 1946, and belongs to an era of unmechanised travel now lost to the rest of us, told me, 'If I'd gone across by camel when I could have gone by car, it would have been a stunt.' To him, exploration meant bringing back information from a remote place regardless of any great self-discovery.

Each definition is slightly different - and tends to reflect the field of endeavour of each pioneer. It was the same whoever I asked: the prominent historian would say exploration was a thing of the past, the cutting-edge scientist would say it was of the present. And so on. They each set their own particular criteria; the common factor in their approach being that they all had, unlike many of us who simply enjoy travel or discovering new things, both a very definite objective from the outset and also a desire to record their findings.

I'd best declare my own bias. As a writer, I'm interested in the exploration of ideas. I've done a great many expeditions and each one was unique. I've lived for months alone with isolated groups of people all around the world, even two "uncontacted tribes'. But none of these things is of the slightest interest to anyone unless, through my books, I've found a new slant, explored a new idea. Why? Because the world has moved on. The time has long passed for the great continental voyages - another walk to the poles, another crossing of the Empty Quarter. We know how the land surface of our planet lies; exploration of it is now down to the details - the habits of microbes, say, or the grazing behaviour of buffalo. Aside from the deep sea and deep underground, it's the era of specialists. However, this is to disregard the role the human mind has in conveying remote places; and this is what interests me: how a fresh interpretation, even of a well-travelled route, can give its readers new insights.