Leading article: The 'hobbit' and the search for truth

The latest salvo in the continuing row over the remains of the "hobbit" found on the island of Flores, Indonesia, raises intriguing questions about the nature of scientific discovery. When can new research findings be accepted as fact, and does the fact that we pose this question prove that all science is merely provisional?

Non-scientists can be forgiven for feeling somewhat confused about this particular bone of contention. The issue is whether the extinct individual who lived on Flores some 13,000 years ago was a member of a hitherto unknown species of human. If so, this dwarfed cousin must have lived alongside some of our early ancestors at a time when it was thought that we were the only humans on the planet.

The counter-argument is that the Flores skull is nothing special, that it belonged to an ordinary member of our own species who suffered a rare congenital disease. If this proves to be the case, the announcement made in 2004 about a new species of dwarf human would turn out to be one of the most embarrassing episodes in the history of human anthropology.

There have been about half a dozen studies of the bones over the past three years, and they appear to contradict each another in terms of whether the Flores individual, a female, truly belonged to a completely new species of human. Some suggest she was; others suggest she was an ordinary woman suffering from microcephaly - a disease of dwarfed stature and unusually small brain.

Scientists are of course used to such disputes, and the bigger the issue at stake, the bigger the dispute is likely to be. It is in the nature of scientific discovery that extraordinary claims demand extraordinary evidence - and that extraordinary egos sometimes become embroiled in unseemly public disputes.

Eventually, the dispute over the "hobbit" will be resolved one way or another. The discovery of a few more skulls similar to the one revealed in October 2004 would, for instance, resolve the debate for most scientists.

No doubt, even with such incontrovertible evidence, there would be those who continue to disbelieve the evidence even when it is placed before their eyes. It is not uncommon for some scientists to continue their maverick line of thought when everyone else has moved on to the next problem. A few "scientists", for instance, still believe that HIV is not the cause of Aids.

But there does come a time when science stops being provisional. Sometimes it happens suddenly with a major discovery that answers all outstanding questions. More often it happens gradually, with a steady stream of new findings. It a long, hard road, but that is the true nature of scientific discovery.