When Lucian Gregory stands in the shadows, this represents the metaphorical darkness of his anarchist beliefs. He rejects the idea that there is any inherent meaning or goodness (light) anywhere in the world, and particularly in the modern, technologically advanced world of the 20th century (which is represented by the street lamp). Gregory’s promise of “a very entertaining evening” and Syme’s characterization of this offer as “idiotic” both foreshadow the next chapter’s events. But Syme’s claim ends up being literally true, whereas Gregory’s is only true ironically, for reasons that he completely fails to understand.