In Chapter 8, Poirot and Sheppard speak with suspects and look around Ackroyd's house. Poirot develops his ethos as a detective by personifying the furniture:
“If those walls could speak,” I murmured.
Poirot shook his head. “A tongue is not enough,” he said. “They would have to have also eyes and ears. But do not be too sure that these dead things”—he touched the top of the bookcase as he spoke—“are always dumb. To me they speak sometimes—chairs, tables—they have their message!”
Sheppard is simply making small talk and, as it turns out, smugly commenting on the lack of credible witnesses to his own crime. Poirot takes seriously the idea that the walls or other inanimate objects might be able to speak, as if they were human witnesses. He explains that the walls would have had to witness with "eyes and ears" if they were to say anything useful, even if they did have tongues. But he goes on to say that the furniture does sometimes "speak" to him. That is, it bears traces of people's interaction with it. For instance, he insists that the position of the chair just inside the room where Ackroyd was killed is worth noting. At the end of the novel, this turns out to be a key piece of circumstantial evidence that allows Poirot to put together the narrative of the evening. Sheppard eventually admits that he moved the chair to block the dictaphone from the sight of those first arriving at the murder scene.
By personifying the furniture, Poirot demonstrates that he is not just any nosy neighbor. In fact, he is a far more expert detective than Inspector Raglan. Raglan is aiming for efficiency in wrapping up the case; therefore, he does not take the time for the minute observations Poirot insists upon. Poirot, by contrast, interviews people and even inanimate objects in his slow but thorough approach to solving crime.
