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We managed to get Marlin through 16 of the 17 stages. The only one we missed was "refusal of the return." Since the movie so abbreviated the return portion of the cycle, we concluded that Marlin probably satisfied this stage as well, but the scene didn't make the final edit. When I have time to watch the movie again carefully, I'll follow Nemo more closely and see if he too goes through all seventeen stages.
We broke Departure down like this:
Call to adventure: Nemo disobeys his father and swims past the drop off to inspect the boat. This scene should inspire Marlin to leave the reef and venture into the open water.
Refusal of the call: Marlin attempts to order Nemo back but refuses to follow his son past the drop off.
Supernatural aid: The scuba diver nets Nemo, the goggles with the Sydney address the "amulet" Marlin needs to start his adventure. [Many students wanted to use Dory as supernatural aid, as she guides and advises—such advice as it is—our hero throughout the adventure.]
Crossing of the first threshold: Marlin makes his ineffective dash after the boat carrying his captured son.
Belly of the whale: Marlin finds himself out in the ocean proper, far from the comforts and familiarity of the reef.
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"Well, what if you ask us about road of trials on the exam?" asked one student who couldn't come up with six.
"Then you say something like, 'Road of trials is a stage that typically comes in series of three. Marlin faces many trials during his adventure, but the three most important ones are A, B, and C.'" Most of them just don't know how to manipulate the evidence to make it look as if they know more than they actually do, and sometimes I feel like a used car salesman explaining how to spin the material to their advantage.
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For Marlin, "atonement with the father" is the most important stage. We concluded that Marlin's "father" was all of the permissive dads who allowed—in Marlin's mind at least—their children to have too much independence. At the start of the movie, Bob [the seahorse], Ted [the octopus], and Bill [the fish] come to mind; they easily relinquish their children to Mr. Ray, the schoolmaster. Marlin initially believes that these fathers are wrong to give their children so much freedom, but as a result of his adventures, he realizes that Crush and Dory are both right about trusting and letting go.
Marlin gets to demonstrate his "atonement with the father" during the next two stages, "apotheosis" and "the ultimate boon." When Dory is scooped up by the fishing boat, Nemo rushes to help her. Marlin, however, doesn't want to lose his son again and tries to interfere. Nemo insists that he can save Dory and explains that Marlin can help as well by getting all of the netted fish to swim down. Marlin relinquishes Nemo's fin, allowing his son to have independence, and then works to inspire the trapped and bewildered catch to swim together toward the ocean floor. Marlin demonstrates god-like ability as the catch overpower the humans who trapped them. Their eventual escape of the net qualifies as "the ultimate boon," the difficult task easily accomplished. I told my students to compare this Marlin to the pathetic version at the beginning of the movie. Pre-adventure, Marlin couldn't save Nemo from a tiny net; now, however, he nearly capsizes an entire fishing boat to free his son.
My students and I never observed Marlin refuse the trip home, but we could get him through the rest of the Return portion of the cycle. We decided that a couple of things could satisfy "magical flight." First, since ocean gossip about Marlin's search for Nemo helped our hero get to his son, then all the creatures who knew the story would help [or at least not hinder] his return to the reef. Since some students believed Dory was supernatural aid, equating her as a loopy Athena to Marlin's dysfunctional Odysseus, Dory could also be the divine aid maneuvering Marlin home. Even the pipe Marlin begins to follow, erected by otherworldly humans, could qualify.
"Rescue from without," that call from the old life to return, has existed the entire movie for Marlin. The reef, its comfort and familiarity, beckons him back. We knew Marlin crossed "the return threshold" because we saw him happily home at the end of the film.
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I read the Joseph Campbell biography at Wikipedia and learned that several folks criticize his hero cycle. For example, Kurt Vonnegut says that it is better named the "in the hole" theory and can be summarized like this: "The hero gets into trouble. The hero gets out of trouble." A careful reading of The Hero with a Thousand Faces reveals that the cycle is more than "into trouble ... out of trouble." Several key stages in Initiation—"meeting with the goddess," "woman as temptress," and "atonement with the father"—and then demonstrating "master of two worlds" in Return are key to refining the hero's personality, fixing flaws that existed before the adventure began. We tend to believe that we "know it all," but hearing and accepting the advice of the goddess shows us that we don't have the full picture, opening us up to the wisdom of others. Navigating successfully past the temptress, who represents the pleasures and diversions of the flesh, allows us to experience the full strength of our own discipline and will. In "atonement with the father," when we see that we too are capable of what we despised or disagreed with, we realize that any two opposing sides have validity. We see that another's opinion is not a cause to argue, just a different "side" of the one universe, someone's wet to our dry, someone's cold to our hot, someone's salty to our sweet.
The cycle isn't a spring break road trip where the hero parties too much and then returns home unchanged. The cycle is instead an opportunity to evolve, the chance to develop an inner strength that makes the hero more adaptable to an ever-changing world. Neo in The Matrix is better able to maximize his potential as the result of his adventure, just as Marlin demonstrates at the end of Finding Nemo.