I have a theory of my own about what this art of the novel is, and how it came into being. To begin with, it does not simply consist in the author's telling a story about the adventures of some other person. On the contrary, it happens because the storyteller's own experience of men and things, whether for good or ill—not only what he has passed through himself, but even events which he has only witnessed or been told of—has moved him to an emotion so passionate that he can no longer keep it shut up in his heart.

What It Means

This is a placeholder explanation generated by the low-overhead model. It interprets "I have a theory of my own about what this art of the novel is, and how it came into being. To begin with, it does not simply consist in the author's telling a story about the adventures of some other person. On the contrary, it happens because the storyteller's own experience of men and things, whether for good or ill—not only what he has passed through himself, but even events which he has only witnessed or been told of—has moved him to an emotion so passionate that he can no longer keep it shut up in his heart." in the context of "Ch. 25: 'The Glow-Worm'" to mean that wisdom is timeless.