"Mamma Mia!" is a lot of things. A fast-paced, fun-filled musical for one. An intense and emotional family drama for another, but take a deeper look at it and there might be even more. Everyone knows the film is about Sophie trying to find out who her real father is while Donna has to deal with the mess of having her three past loves resurface in her life, but I'm sure we can agree that's a bit chaotic.
The film has general craziness and revelations and passionate love all thrown together to the point that I am reminded of Greek tragedies. Now the film isn't tragic in the slight, but Sophie's opening "I Have A Dream" scene is reminiscent of a play's prologue and the musical intervals could easily mimic the chorus that takes place between each scene of spoken-word in a play. On top of that, Sophie's issue with her unknown father — or rather, the uncertainty of which one — is similar to a hero's struggle. She does not know her father and therefore feels unsure of her identity, which could easily be the call to adventure found in Joseph Campbell's monomyth structure. Of course, if a strong argument were to be made, her journey wouldn't be able to begin until she leaves the island, so we won't focus on that.
Instead, the main evidence of a mythic presence is Donna's past and how the island reacts to it returning it. The only mythical figure named in the movie is Aphrodite, the Greek goddess of love because the film must name-drop their tourist attraction, "Aphrodite's Fountain." In reality, this fountain is fake and only exists for the film, but that doesn't matter. What matters is that its residence in the villa makes the island significant to Aphrodite and in turn, everyone on the island as well.
Again, it seems rather chaotic, but in both Greek myth and dramas, there is often a godly presence. This time, it happens to be Aphrodite. In one of the first musical numbers, Donna sings "Money, Money, Money," after the fountain was mentioned only moments before. The song is about troubles with wealth and yet, for her, it is sung in the context of needing general assistance. During this number, the film shows Sam, Bill, and Harry arrive on the island and at the end, the dolphin mosaic cracks beneath Donna's feet.
At the end of the film, it is revealed this is the exact location where Aphrodite's fountain lies.
If this isn't godly foreshadowing, I'm not sure what is. When Sophie first talks to her three fathers, she states that it was a "long shot they'd even reply" and that something must have lured them there, a "siren call maybe." This doesn't have to be just playful dialogue, it could very well be said with purpose. Perhaps something did lure them there, a mythic presence hovering over the situation. It gets stranger if you consider the amount of supporting cast who arrive at the island and ultimately form several trios, which are ever-present in Greek mythology, from the Moirai to the Charites. The details, or rather Aphrodite's influence, are everywhere.
By the end of the film, Sophie does not marry Sky, which is a prominent feature of the story at the beginning. That of course, does not mean they are not in love. Sophie and Sky agree to depart from the island and go on an adventure. Instead of their marriage, Donna gets to marry her true love, Sam, and Sophie gets not one father but three, as the triad decides to love her equally as their daughter. It's a very happy ending, almost too good to be true, as myths can often take an ugly turn.
Yet, the last musical number, at the wedding reception, closes the film by having the fountain of Aphrodite erupt out of the ground and around the characters as they dance atop it. If we are to argue there is a mythic presence, a claim could be made that at the beginning Aphrodite was unsatisfied with the events happening on her island. Then, in the end, with our heroes triumphant, the fountain reappears as a gift from her. Given the tone of the film, these intricacies are likely not done on purpose, but the evidence is substantial and — if we're being honest — pretty entertaining, just like the film itself.
With more pondering, other connections to Greek myth and plays are sure to arise, but for now, it's safe to say that "Mamma Mia!" has quite a mythic touch, whether or not the characters are aware of it.