During the last decade and a bit, there were a number of films based around alternate timelines or divergent life paths following the different outcome of some minor choice see the likes of Run Lola Run (1998), Sliding Doors (1998), which is namedropped here at one point, Twice Upon a Yesterday (1998), Me Myself I (1999), The Butterfly Effect (2004) and Edge of Tomorrow (2014), among others. All of these fall into a familiar plot of showing the wildly divergent consequences that would occur if the choices in someones life were made differently. Coherence takes up the same theme but roots itself in scientific ideas of quantum superimposition and wave function collapse the very title coherence is a term from physics that relates to the way in which quantum wave functions (the possible and potential states of a particle) interact with one another. (Schroedingers Cat, the thought experiment that exemplifies quantum behaviour and observability, is thrown about at one point). From this, the film derives the notion of a seemingly infinite number of variations of the same people, based around the different choices about such things as which colour glowsticks they take, which dice numbers they roll or which objects are placed in the box, interacting with one another.
The film seems nothing remarkable at the outset, although you do admire the fact that Byrkit and his cast have clearly spent a good deal of time rehearsing together, getting their interactions are tight and well polished. Things then start to get fascinatingly weird the discovery of the box taken from the house across the street that contains photos of everybody moreover ones that could only have been taken that night; where Hugh Armstrong goes to put a note on the door of the other house stating their non-threatening intentions whereupon a knock comes at the door and they are startled to find a note affixed there that says exactly the same thing as the one in Armstrongs hand; or the jolt when the random dice number rolls are assigned to the photos and the realisation that not all of the party come from the same house. The film then starts to get fascinatingly interwound like the immediate hostility that breaks out between the two houses and how the group start plotting to kill/blackmail their other selves and the jolt realisation that two of the people who returned from across the road are not the same ones that set out. The film makes a wonderfully wound pretzel out of the interplay between who is which self and where they come from. The final coda of the film where one of the party makes it to what they think is a house that is unaffected only to be caught out is fantastic.
Byrkit has clearly saved on budget by shooting the entire film in someones home and the street outside. This set-up follows the lead of several recent end of the world films This is The End (2013) and in particular Its a Disaster (2012), which was also focused around a group of people gathered for a dinner party in having the entire catastrophe experienced by a group of people inside a suburban home as everything happens outside their doors.
James Ward Byrkit has brought together a cast of almost knowns. Emily Foxler and Maury Sterling have played a host of tv guest roles and film bit parts. Nicholas
Brendon, who probably gives the best performance in the film, is best known as a regular on tvs Buffy the Vampire Slayer (1997-2003) he has an amusing line where he claims to have been a regular on tvs Roswell (1999-2002), one show that Brendon did not actually appear on (one wonders why they simply didnt use Buffy here). Elizabeth Gracen, a Playboy model known for taking her clothes off in various roles in the 1990s and as the lead in Highlander: The Raven (1998-9), appears as the New Age host of the party, albeit much older now than anything one saw her in previously. The bespectacled and shy member of the group is played by Lorene Scafaria, better known as the writer of Nick and Norahs Infinite Playlist (2008) and as writer/director of Seeking a Friend for the End of the World (2012).