RECENTLY ARCHAEOLOGISTS have come to recognise that the way we see the past is to a large extent influenced by our present conceptions, particularly our present conception of time. They have therefore come to see the value of looking at the past through different time lenses.

I proposed to examine the entire archaeological record through a time lens derived from the ancient Sanskrit writings of India, especially the Puranas, or histories. The writings contradict the dominant view that anatomically modern humans arose between 100,000 and 200,000 years ago from more ape-like ancestors.

An examination of the entire archaeological record accumulated since the time of Darwin should reveal two things: extensive archaeological evidence for extreme human antiquity, and a process of knowledge filtration whereby this evidence was edited from the record because it violated evolutionary conceptions. Both predictions came true. Here is a representative case. In 1880, Harvard University published a monograph by geologist JD Whitney titled the "The Auriferous Gravels of the Sierra Nevada of California". In this work, Whitney recorded discoveries of anatomically modern human bones and artefacts in the California gold mines. According to modern geological reports, the oldest of the discoveries come from layers of rock more than 50 million years old. We do not hear much about these discoveries today because of the process of knowledge filtration.

William B Holmes, an anthropologist at the Smithsonian Institution, said in the Smithsonian Institution Annual Report (1899), "Perhaps if Professor Whitney had fully appreciated the story of human evolution as it is understood today, he would have hesitated to announce the conclusions formulated, notwithstanding the imposing array of testimony with which he was confronted." In other words, if the facts did not fit the theory of human evolution, they had to be set aside. And that is what happened.

In the 1970s, American archaeologists were conducting excavations at Hueyatlaco in central Mexico and uncovered stone tools and weapons, including projectile points. They were the kinds of artefacts archaeologists attribute to humans like us, not any kind of ape-man.

To date the site, the archaeologists called in a team of American geologists, including Virginia Steen-McIntyre. Using several of the latest methods, the geologists arrived at an age in excess of 250,000 years for the site. The archaeologists refused to publish the date. Steen-McIntyre, operating independently of the archaeologists, eventually found a scientific journal (Quaternary Research) that would publish the dates she and her colleagues from the United States Geological Survey had obtained.

On 30 March 1981, Virginia Steen-McIntyre wrote to Estella Leopold, the associate editor of Quaternary Research: "The problem as I see it is much bigger than Hueyatlaco. It concerns the manipulation of scientific thought through the suppression of 'Enigmatic Data', data that challenges the prevailing mode of thinking. Hueyatlaco certainly does that! Not being an anthropologist, I didn't realise the full significance of our dates back in 1973, nor how deeply woven into our thought the current theory of human evolution had become. Our work at Hueyatlaco has been rejected by most archaeologists because it contradicts that theory, period."

Multiply these two cases by several hundred, some of which go back tens of millions of years (as I have documented in my book The Hidden History of the Human Race), and we can begin to sense the true dimension of the problem.

Only the other day, I saw a BBC report that archaeologists were puzzling about evidence for aesthetic painting found in Zambia at a site thought to be perhaps 400,000 years old. Too old for humans like us? Maybe not.