1. Claim
2. Radiocarbon dating of Quran manuscripts, Dr. Shoemaker argues, is not entirely reliable because sometimes the same folio or the folios of the same manuscript show widely different dates. Carbon dating can’t be used as the sole measure for dating manuscripts precisely.

1. Response
2. He assumes that if one lab produces an inconsistent result, it automatically means the C14 principle is unreliable. Scholars don’t rely solely on C14 for dating manuscripts. Its results are paired with other analyses like paleography and codicology. Thus, no one claims C14 is the sole method to confidently date Quran manuscripts. The Lyon lab reported an unexpected date for DaM 01-27.1 (eg. 433-599 CE). Such inconsistencies can arise from contamination, where extraneous carbon might be introduced during sample collection, handling, or processing. (Deroche, 2013, p. 13)

Contamination can skew the carbon isotope ratio, leading to inaccurate age estimates. When discrepancies like this occur, especially if other labs produce consistent results that match each other, scholars typically cross-reference with other dating methods or retest the sample. The inconsistent result is approached with caution, and the broader consensus from multiple tests and methods is given more weight in scholarly conclusions. 14 testing results for DaM 01.27.1:

• Folio 2: 589–650 CE (95.4%)
• Folio 11: 611–660 CE (95.4%
• Folio 13: 590–650 CE (95.4%) – Combined analysis dates codex to 606–649 CE with 95.4% probability.

(Marx & Jocham, 2020, p. 216)

1. Lyon lab C14 results for Dam 01.27.1:
   • Folio 2: 543-643 CE
   • Folio 11: 433-599 CE
   • Folio 13: 388-535 CE
2. Comparison of both lab results:
   • For Folio 2: The Lyon lab’s range is broader and starts earlier than the Corpus Coranicum’s results, although there’s some overlap.
   • For Folio 11: The Lyon lab suggests a much earlier dating that barely touches the 7th century, while the Corpus Coranicum strongly anchors it in the 7th century.
   For Folio 13: The discrepancy is even more pronounced, with Lyon’s date being significantly earlier and not overlapping with the Corpus Coranicum’s range. The dates provided by the Lyon lab for the Sana’a folios appear to be inconsistent with the Corpus Coranicum data, particularly for Folios 11 and 13. Such discrepancies raise questions about potential contamination or methodological issues in one of the labs. Given the consistency within the Corpus Coranicum’s results and their alignment with expected historical contexts, the Lyon lab’s results seem more likely to be outliers. Marx & Jocham recognize the irregular dating of the Sana’a DaM 01-27.1 by the Lyon lab as problematic. However, they emphasize that this individual discrepancy does not compromise the overall reliability and credibility of C14 dating as a method. (Marx & Jocham, 2020, p. 206)

1. Radiocarbon dating discrepancies observed for the Dam 01-27.1 (Lyon ab) echo challenges faced with the Dead Sea Scrolls. Specifically, the Isaiah Scroll from Qumran, while largely aligning with paleographic estimates, had some C14 results that differed between labs. Such variances can arise from differences in calibration, sample conditions, or laboratory procedures. These instances highlight the importance of corroborative testing and the value of scholarly consensus, treating C14 dating as one facet of a broader evidentiary framework.
2. Another folio from DaM 01-27.1 was dated at the AMS Lab, University of Arizona (Sadeghi & Bergmann 2010). Results indicate:
   • 68% probability of dating between 614-656 CE
   • 95% probability of dating between 578-669 CE

In summary, the C14 results from both Sadeghi & Bergmann and the Corpus Coranicum are notably consistent, further reinforcing the general consensus on the 7th-century dating of Sana’a DaM 01-27.1 manuscript.

See also: Marjin van Putten’s response.