The quote from The Dick suggests that Denny's involvement in arson cases might be outdated or exaggerated, implying that his experience with fire and law enforcement dates back to primitive times when early humans used basic methods like rubbing sticks to start fires. This humorous comparison reinforces the idea that Denny's supposed expertise is rooted in ancient, primitive practices rather than modern techniques.

Overall, the passage uses humor and exaggeration to diminish Denny’s credibility in contemporary arson cases, hinting that such issues, if they ever existed at all, are as old as human civilization's earliest days. It emphasizes the contrast between primitive fire-starting and modern criminal investigations, suggesting that Denny’s past experience may be more storytelling than fact.