Natori makes an extraordinary claim for a 17th-century text: monsters encountered at night are imaginary. He states flatly that he walked alone at night and found no monsters, despite cultural beliefs in supernatural creatures.
His explanation: foxes and raccoons can appear to transform if a person's chi is weak. Weak-minded samurai susceptible to hallucination will perceive these animals as supernatural. Strong-minded samurai will perceive them as animals.
The implication: supernatural experiences reveal weakness of the observer, not reality of the supernatural.
"Samurai should not speak publicly of supernatural experiences (reputation damage)."
This is rational pragmatism: claiming to have seen monsters damages your credibility. The samurai who wants to be taken seriously as a warrior must claim rational experiences only.
This skepticism is remarkable for a text written in 1654-1708, during a period of widespread supernatural belief in Japan. Natori maintained rational empiricism even while using spiritual frameworks (chi, goshi) to explain warrior excellence.
The integration: spiritual concepts like chi can be explained rationally (nervous system function). Supernatural claims cannot.