Johnny's diary is more revealing and, daily reports aside, showcases the high example Johnny set for himself, even before his illness. The "Gunther Philosophy" is one he lived by all along, and the statement "No immortality" is one he always acknowledged but never let defeat him. Johnny may have indeed left his diary out on occasion to communicate to his parents indirectly, but even his rare lamentations—"Oh how tired I feel"—are far from self-pitying. As Frances points out, he soldiered on despite these setbacks and not only for himself, but because he was "bearing out burden"; perhaps Johnny transcribed only his mildly painful thoughts, knowing his parents would read them, and spared them his more fatal ideas.

The diary also records his reading the book Human Destiny, which tries to prove the existence of God through scientific reasoning. While still a staunch atheist, Johnny sees what is worthwhile about religion, especially in its attempts to explain the mysterious. Perhaps he is trying to come to grips with his death, another mystery; in either case, he remains open-minded until the end, willing to explore everything, even that which he steadfastly denies. Frances, on the other hand, tries to understand death through the joy of life and seeks an answer not in religion, but by focusing on Johnny and earthly delights. She feels that her and other people's love for him, and his love for them and for his various pursuits, is what one should remember from a life. Indeed, she seems more aware of the possible joys and loves of life now, so Johnny's life—and death, which she now sees as inseparable from each other—continues in her heart.