How did Karl Lachmann’s method classify and evaluate manuscript copies?

Karl Lachmann is widely recognized for establishing the genealogical, or stemmatic, method of textual criticism, which revolutionized how scholars classify and evaluate manuscript copies of classical texts.1

The Genealogical Method

Lachmann’s approach moved away from the earlier practice of relying on a single "best" manuscript. Instead, he sought to determine the definitive text by reconstructing the history of its transmission. His method involved:2

• Identifying Relationships: By analyzing shared errors and variants across different manuscripts, scholars could group them into families or branches of a "family tree" (stemma).13
• Determining Lineage: This process allowed editors to trace the descent of extant copies back to a common ancestor, helping to distinguish between original readings and later corruptions or interpolations.14
• Eliminating Inferior Copies: Once the genealogical relationships were established, manuscripts that were shown to be derived from other surviving copies could be discarded as redundant, allowing the editor to focus on the most reliable witnesses.15

While Lachmann’s rigorous application of this method provided a scientific framework for classical scholarship, it was later criticized for its potential rigidity, particularly when applied to "contaminated" traditions where manuscripts do not follow a simple, linear descent.5