The number zero is something we all take for granted, yet its conceptual origin has eluded archaeologists and historians. An updated analysis of an ancient Indian manuscript is shedding new light on this longstanding mystery, showing that the symbol that would eventually evolve into the number zero emerged at least 500 years earlier than previously thought.
In this close-up image, you can see the use of a dot as a placeholder in the bottom line. This dot evolved into the use of zero as a number in its own right. (Image: Bodleian Libraries, University of Oxford)
Carbon dating of the Bakhshali manuscript, a sole surviving copy of a mathematical text, has pushed back the time of origin to between 224 to 383 AD, rather than the 9th and 12th centuries as previous research had suggested. The Bakhshali manuscript is littered with a symbol for zero, as conveyed by a solid black dot, making it the oldest known example of the symbol that would later evolve into a number in its own right.
The document was discovered buried in a field by a local farmer in 1881 near the village of Bakhshali in what is now Pakistan. It was sent to the Bodleian Library at Oxford University in 1902, and it’s been there ever since. An early analysis of the text identified the language as being a Buddhist Hybrid Sanskrit; the manuscript contained hundreds of zero symbols and was likely used by merchants who needed a reference for their daily trading activities. But the precise age of the document remained elusive, which is why in early 2017, researchers from the University of Oxford’s Bodleian Libraries and the Oxford Radiocarbon Accelerator Unit collaborated on a project to finally carbon date the document.
Carbon dating shows the Bakhshali manuscript dates from 224-383 AD, making it one of the earliest known examples of the use of zero (written as a dot) an as a placeholder, that is, the use of zero to indicate orders of magnitude in a number system. (Image: Bodleian Libraries, University of Oxford)
Prior investigations into the age and origin of the Bakhshali script suggested it was written sometime between the 8th and 12th centuries, but that analysis was based on the style of writing, the literary and mathematical content, and other factors. The new carbon dating shows why an origin date was so difficult to nail down; the manuscript consists of 70 brittle leaves of birch bark, composed of material from at least three different historical periods.
It’s worth pointing out that this analysis has yet to be peer-reviewed and published in a scientific journal.