Children, only animals live entirely in the Here and Now. Only nature knows neither memory nor history. But man -- let me offer you a definition -- is the story-telling animal. Whereever he goes he wants to leave behind not a chaotic wake, not an empty space, but the comforting marker -- buoys and trail-signs of stories. He has to go on telling stories, he has to keep making them up. As long as there's a story , it's all right. Even in his last moments, it's said, in the split second of a fatal fall -- or when he's about to drown -- he sees, passing rapidly before him, the story of his life. (p.63)
The preceding passage illustrates the reoccuring idea in the novel that man needs stories and history to give substance and meaning to an empty existence. This explanation of story-telling could provide the reason why Tom Crick feels the need to tell family, personal, and natural history. He wants to impose meaning on to his existence. His family history gives a context to his personal history while natural history provides a context for man's history. Since everything is so neatly explained, man will not have to face the void of reality. Even at the moment of death, he is comforted by the stories he has created to divert his attention from the empty space of his existence.