The quote from Philip K. Dick emphasizes the thin line that separates sanity from insanity. It suggests that this distinction is not only fragile but also hard to define, as it can change and evade our understanding effortlessly. The imagery used, comparing the boundary to a razor's edge and a hound's tooth, illustrates how precarious and sharp this division can be.

Moreover, Dick speculates that sanity and insanity may not even be real concepts, likening them to a phantom that exists only in our perception. This idea raises questions about the nature of reality and mental health, inviting readers to ponder if these categories truly hold significance or if they are merely illusions in the human experience.