Hallmark of Science in recent archaeology
Recently I came across a beautiful example of the application of a fundamental feature of science: rigorous evaluation of a hypothesis and evaluation of evidence in support of those ideas. And I found it in archaeology, no less! For your convenience, the entire story is quoted below.
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The unique power of science lies in its extreme openness to new ideas coupled with a rigorous evaluation of the evidence offered in support of those ideas.
In science, even seemingly heretical notions can be proposed - Earth is round, continents move, bread mold is medicine - but theories must be supported by evidence. When they are refuted by the evidence, they must be discarded.
In 2005, Silvia Gonzalez, an archaeologist with the Liverpool John Moores University, reported the discovery of apparent human footprints in volcanic ash in the Valsequillo Basin south of Puebla, Mexico.
She and her colleagues said those footprints were more than 40,000 years old.
That was a bold claim with startling implications for our understanding of the peopling of America. Several lines of evidence support a date of about 14,000-15,000 years ago for the first discovery of America by humans. If confirmed, 40,000-year-old human footprints would more than double the antiquity of the human colonization of this hemisphere.
Naturally, there was considerable scrutiny.
Geoscientist Paul Renne of the Berkeley Geochronology Center and several colleagues obtained dates for the ash using argon dating as well as paleomagnetism. They concluded the ash and any "footprints" that might be in it were 1.3 million years old. They argued that the identification of the markings in the ash as human footprints was erroneous.
Having humans in America 40,000 years ago is improbable, but it's still worth considering. However, human ancestors in America 1.3 million years ago is practically impossible.
Homo erectus, the most far-faring human species alive at that time, did not have the technology to survive either a trip across the frozen expanse of Siberia, or to voyage across an ocean to reach America.
Initially, Gonzalez and her colleagues defended their less-extreme dates for the ash, but in the latest issue of the Journal of Human Evolution, they report new argon dates that corroborate the 1.3 million-year age of the Valsequillo deposits.
Moreover, they now accept that the "footprints" actually are modern quarry marks that have been modified by natural erosion so that they only resemble human footprints. In a few cases, the resemblance is admittedly uncanny.
Gonzalez and her team deserve a lot of credit for doing the necessary work to test their original claim and for publishing the results. This does not represent a failure of science. Rather, it is indicative of one key to its great success.
Data are collected and tentative interpretations are offered. Those interpretations must be testable and capable of being refuted or supported by evidence. We learn something valuable even when theories are overturned. Philosopher of science Karl Popper wrote that such falsifications reveal where we have touched reality.
Interpretations that are not testable are not properly considered to be part of the scientific enterprise. The physicist Wolfgang Pauli famously dismissed them as "not even wrong."
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Source: Archaeology Daily |
