Matching Meaning at Scale: Evaluating Semantic Search for 18th-Century Intellectual History through the Case of Locke

TL;DR

This paper assesses the effectiveness of semantic search in uncovering implicit references to Locke in 18th-century texts, revealing its advantages over lexical methods and highlighting current limitations.

Contribution

It demonstrates that semantic search can identify more implicit idea transmissions in historical texts than traditional lexical approaches.

Findings

Semantic search retrieves more implicit references than lexical methods.

Linguistic diagnostics show a 'lexical gatekeeping' effect in retrieval.

Semantic retrieval has potential but also current limitations.

Abstract

While digitized corpora have transformed the study of intellectual transmission, current methods rely heavily on lexical text reuse detection, capturing verbatim quotations but fundamentally missing paraphrases and complex implicit engagement. This paper evaluates semantic search in 18th-century intellectual history through the reception of John Locke's foundational work. Using expert annotation grounded in a semantic taxonomy, we examine whether an off-the-shelf semantic search pipeline can surface meaning-level correspondences overlooked by lexical methods. Our results demonstrate that semantic search retrieves substantially more implicit receptions than lexical baselines. However, linguistic diagnostics also reveal a "lexical gatekeeping" effect, where retrieval remains partially constrained by surface vocabulary overlap. These findings highlight both the potential and the limitations of semantic retrieval for analyzing the circulation of ideas in large historical corpora. The data is available at https://github.com/COMHIS/locke-sim-data.