Lachmann Builds a Family Tree Out of Copying Mistakes

Textual criticism compares surviving manuscript copies of the same text against one another at every point where they disagree, using the pattern of shared errors and variants to reconstruct a family tree of how the surviving copies descend from one another and from lost intermediate copies, and from that tree to recover the reading most likely closest to the text's earliest recoverable form. The German classicist Karl Lachmann gave the method its rigorous modern form in the 1830s, applying it first to classical texts and then, controversially, to the Greek New Testament, arguing that manuscript relationships could be established from shared copying errors with the same logical rigor a naturalist applied to classifying species by shared inherited traits.

No autograph manuscript survives for almost any ancient scripture, which means every scripture the atlas describes is known only through a family of later, disagreeing copies, and textual criticism is the discipline that establishes which reading in a disputed passage has the best claim to being original. Where manuscript witnesses to a scripture genuinely disagree and no consensus reading has been established, the atlas records that disagreement explicitly rather than silently adopting one textual tradition's reading as the text.