In 1928 Joseph Bédier audited a field's published family trees and found they had the shape that let editors pick the answer they wanted. Three disciplines that hit genuine underdetermination, and what each does about it.
The New Testament survives in about 25,000 manuscripts. Somewhere between three witnesses and several thousand, counting documents stops being the same activity as counting sources.
Scribal errors are not random. Each named type has a trigger in the script itself, which means the corruption profile is a property of the medium rather than the copyist.