The theme of "The Ambitious Guest" is the universality of human ambitions and the vanity of these human ambitions. The young guest is filled with ambition even though he has no idea of what he wants to accomplish. Furthermore, he is sure he will accomplish something that will make him famous before he dies. He, along with the whole family, is living in the shadow of a mountain that is continually threatening to wipe them off the face of the earth--and yet they are all hoping to realize their dreams.
Many writers have commented on human ambition. Among them is Lajos Egri, author of excellent book The Art of Dramatic Writing.
Immortality! Yes, we all crave attention. We want to be important, immortal. We want to do things that will make people exclaim, "Isn't he wonderful?" The urge to be outstanding is a fundamental necessity in our lives. All of us, at all times, crave attention.
According to Alfred Adler, a colleague of Sigmund Freud and C. G. Jung:
To be a human being means to possess a feeling of inferiority, which constantly presses towards its own conquest. . . . The greater the feeling of inferiority that has been experienced, the more powerful is the urge for conquest and the more violent the emotional agitation.
And according to the ancient Roman historian Tacitus:
The desire for glory clings even to the best men longer than any other passion. (Etiam sapientibus cupido gloriae novissima exuitur.)
John Milton calls the desire for fame "That last infirmity of noble minds." And Dante Alighieri writes: "Worldly renown is naught but a breath of wind, which now comes this way and now comes that, and changes name because it changes quarter."
In "The Ambitious Guest" Hawthorne is depicting a family that is a microcosm of the human race. Everybody comes into the world with great expectations, but everybody is subject to the whims of fate. The mountain hurling rocks at this family in their fragile home is symbolic of the human condition. No matter how much a person may accomplish, driven by his ambition, sooner or later he has to die and lose everything he has acquired. Even his fame, if he manages to achieve it, will not last long.
The moral of the "The Ambitious Guest," rather than the theme, seems to be that we should be more modest in our ambitions and our expectations. A quiet, simple life is preferable to one driven by a thirst for glory.
Julius Caesar was perhaps the most ambitious man who ever lived, and yet he was unexpectedly stabbed to death on the very day he planned to be crowned king. Caesar is a good example of what Alfred Adler said about the urge for conquest being inspired by feelings of inferiority. Caesar had a frail physique and suffered from bad health all his life. He had epileptic seizures, among other ailments, as mentioned in Shakespeare's Julius Caesar. He forced himself to endure all kinds of hardships in his attempt to overcome his physical weakness, and he became the greatest of all Roman conquerors. Plutarch says that he was responsible for the deaths of a million enemy soldiers.
Humility is the most difficult of all virtues to achieve; nothing dies harder than the desire to think well of oneself. - T. S. Eliot