An interesting feature of the language of many Daoist texts is their atypical idealization of Darkness and Obscurity, which contrasts with the positive connotations of Light and Clarity in virtually all great philosophical traditions. This article highlights a formerly unnoted difference between the received and the excavated Guodian 郭店 versions of the Laozi 老子, which reveals an interesting change in the use of Light/Darkness symbolism through the evolution of the text: while the received Laozi uses both metaphorical schemes to roughly (...) the same extent, the presumably earlier Guodian Laozi lacks almost all of the “bright” references that appear in later recensions, thus constituting a much “darker” version of the text. The article discusses the philosophical meaning of this terminological shift and the possible reasons for its occurrence, and closely analyzes three cases in which this process of “textual illumination” seems to have taken place during the transition between the Guodian and received version of the text. Alongside more specific implications such as the formerly unknown linkage between ming 明 and chang 常, a suggested stratification of chapter 55, and the possible relationship between the proto-Laozian materials and the Zhuangzi 莊子, this article also proposes a more general hypothesis according to which the absence of light metaphors in the Guodian version represents the jargon of an earlier “dark” stratum of Daoism, traces of which were preserved in some of the texts known to us today. (shrink)