One way of striving for objectivity is to reverse roles and see things from a non-human point of view. From Pongo's perspective in 101 Dalmatians, the humans in his household became his pets. The bull in the ring, fulfilling his nature in a fight to the death, defies the well-meaning human critics who would prefer to kill him ignominiously in an abattoir. The cabbage screams under the garden knife. A more radical way to evade our prejudices is to try to imagine mankind's place in creation as a cosmic scrutineer might see it, beholding us from a distant planet without bias in our favour. More arrogant life-forms than ours would, of course, overturn our views on the relative importance of our human cultures and civilisations and question our conventional versions of our history. If endowed with hindsight as well as cosmic vision, they might also be able to look back over the history of our relationship with other species. They would then detect - and perhaps endorse - the modest place in creation which past civilisations assigned to man.
No one knows how or when human beings got the idea that they were better than the rest of nature. Primitive wisdom deferred to other species bigger, stronger, tougher or faster than man. Animals who were enemies were treated with awe, those who were allies with admiration. The Mesolithic hunters who left a graveyard intact at Skateholm on the Baltic accepted their dogs as full members of society, burying them with the spoils due to prowess and, in some cases, with more signs of honour than are found in the graves of their men. Households such as mine, which have scatter- cushions embroidered "Dachshunds are people, too", have a long tradition behind them.
Until they began successfully to exploit the natural environment, people feared it. They appeased it with offerings. They mimed it in rites of zoomorphic dance. When they made artefacts and buildings, they paid trees and creatures the homage of imitation. Instead of assuming that people were made in the image of God, they fashioned their own gods to look like animals. When they affected the supreme arrogance of divine disguise, they did so in pelts and feathers, horns and beasts' head-masks.
In the civilisation usually praised or blamed for inventing our notion of our own supremacy - those of the ancient Chinese, Indians, Greeks and Jews - the claim that man is monarch or steward of the planet cannot be traced back very far: not beyond a period well into the last millennium before the Christian era. Once established, it was not widely shared.
Egyptian civilisation clung to gods with the faces, for instance, of crocodiles and dogs. The civilisations of the Americas worshipped the parts of the environment they ate. The mutual sustenance of man and corn did not imply the superiority of the human partner. On the contrary, it was people who tended the cobs in a lowly rite of servitude, while the corn seemed to exercise the divine prerogative of self-immolation for its worshippers' good. There is no practical paradox in the idea of a god who sacrificed himself to nourish his devotees: the God of Christians does it every day.
In most of the rest of the world, for most of the time, similar attitudes have prevailed. In collaboration with other parts of nature, people have thought of themselves as equal or inferior partners. Or, struggling for survival in hostile environments, they have eyed other species as equal or inferior competitors.
Until about 300 years ago in western Europe, it was still common for animals to have legal rights practically on a par with humans. Rats that despoiled barns, grasshoppers that ravaged crops, swallows that defecated over shrines and dogs that bit people were tried in courts for their "crimes", represented by counsel and, sometimes, acquitted.
In Wales and France, pilgrims visited the shrines of canonised dogs: there could be no more powerful demonstration of the moral equivalence of man and beast. Today's animal rights activists are ultra-conservative revolutionaries who want to put the clock back hundreds of years.
Man's claim to superiority has arisen gradually, but it has had powerful authorities on its side. It is made explicit in Genesis: "Every living thing that moves will be yours." God says to Noah, "even the foliage of the plants, I give you everything". The Stoics, too, taught that nature exists only to serve man's needs. Renaissance humanism - the collective narcissism of an entire species - has made the doctrine part of the legacy of the modern world.
Today - in the West, at least - most of us probably think humans are God's best shot or, in secular language, the climax of evolution. Even the liberators of veal calves are moved by compassionate condescension of inferior fellow creatures. Yet still, in other cultures, people believe in material angels and demons who, inseparable from nature, patronise or imperil mankind with their daunting powers.
The Japanese, with their traditional mental picture of nature teeming with gods, are surely more typical than we are. In Hindu tradition, which assigns man top place as the last resort of reincarnations, human supremacy is only tentatively asserted. Non-human forms of life are reverently handled in a spirit similar to what we now call "deep ecology": not just conserving the environment or refraining from irresponsible exploitation of it, but treating it as sacred. In EM Forster's A Passage to India, when the missionary conceded that monkeys could enjoy "their collateral share of bliss", the Brahmins asked, "What about insects, oranges, crystals and mud?" Scientists who think life may have originated in a chemical accident ought not to blench at the inclusion of crystal.
Before we dismiss opinions so widely shared, we should look at the evidence for mankind's supposed superiority and try a bit of disinterested self- criticism. Most of what is usually cited as evidence is claim-staking for a privileged place in the world. Much of the rest are mere outpourings of a human identity crisis: imperfectly convincing attempts to draw the line between man and other animals.
Aristotle thought people were elevated by their social habits, but an objective eye might see the predictable, collaborative politics of ants or bees as providing a better model than ours.
Man has often boasted of his unique ability to fashion tools: a student of planet Earth, from somewhere else in the universe, might see this only as evidence of unique physical defectiveness. It is true that only people prepare food before they eat it, except for one species of monkey that likes to wash nuts, but it would be unpardonably arrogant to make a virtue of our peculiarity.
We congratulate ourselves on the size of our brains, which is a good test, but only by our own standards. Some of us like to claim that humans are the only property-owning animal, but even if this were true - for tribes of monkeys defend their turf and dogs fight over bones - it would be a recommendation only from arguable ideological standpoints.
Cognition, higher consciousness, even perhaps conscience and soul are attributes we assign to ourselves in our desire for self-differentiation. We suppose that we alone have a notion of transcendence - but, like most of our claims to unique sagacity, this is the result of our inability to communicate with other species. It is like dismissing as dumb the people whose speech you cannot understand.
No one has yet taught a chimpanzee much human language. On the other hand, even the most dedicated human students have made only rudimentary progress in talking to gorillas. Experimenters are disappointed when the chimpanzees fail to respond to efforts to teach them sign-terms for abstract concepts. Gorillas, no doubt, suffer from frustrations of their own with human interlocutors.
The very attempt to distinguish ourselves from animals is a delusive form of self-flattery. The line has never been satisfactorily drawn. Tribes commonly have no word for "man" that includes members of other tribes. They refer to those excluded as "monkeys". In the 18th century, theorists wearied readers with efforts to prove that orang-utans were human. The hero of one of Thomas Love Peacock's satires was an orang-utan who, possessed of every atonal faculty except speech, acquired, with a reputation as "a profound but cautious thinker", a baronetcy and a seat in the House of Commons. Pygmies, Hottentots and Aborigines, meanwhile, were relegated to sub-humanity. Now we prefer to classify humans as animals, linked by evolution in an embracing continuum, and have done with it. But, by comparison with our fellow creatures, we persist in giving ourselves top ranking.
When the astral scrutineers review the evidence and try to identify Earth's top species, they will find some points in our favour. It is, for instance, an objective fact about us humans that we can survive in more environments than almost every other creature - except for the parasites and micro- organisms we carry inside us wherever we go. We will probably pass muster as the species with the best collective memory: as far as we know, our ability to record information makes us best equipped for what we call progress and best placed to exploit vicarious experience - though we may be found wanting if judged by the use we make of their privilege.
And, just as historians measure societies relative to one another by their effectiveness in making war, so we shall be seen to advantage in our power to destroy other species. Only a few micro-organisms - whom our cosmic observers may admire for the rapidity and mutability with which they evolve - exceed us in this respect. Most other sources of human pride are hard or impossible to value by objective standards.
Our biggest rivals for the scrutineers' esteem will probably not be other animals. The consciousness from which we exempt the microbes may be discounted as ascribed, in a form or by a measurement unknown to us, to other species.
We may not have to await the day of the triffids to be judged inferior to plants. During our recorded history, we have helped to make some plants - especially wheat, maize and rice - among the most rapidly adapted and widely grown species in the planet. We think we have exploited them; but in measurable terms, they have done rather well out of us. From the viewpoint of the astral scrutineers, it will look as if they have cunningly manipulated mankind for their own propagation and distribution.
Species like these, with which we live in mutual dependence, may not be strong enough to survive us, but compared with many others - especially plants - we will be seen by the cosmic judges as fragile vessels, exceptionally prone to self-destruction. The conservation movement has made us worry about the durability of the natural world, as if nature could not last without mollycoddling by us. Trees, lichens, weeds were here before us. They will be here after we are gone: what objective test could be more conclusive? A still imperfectly domesticated nature is waiting to take revenge.
When the Prince of Wales talks to his plants, let us hope that he does so without condescension. One day, they may be king.
The writer is the author of 'Millennium' (Bantam Press, pounds 25)