If anyone can take brooding existentialism to a new level of divisiveness, Algerian author Boualem Sansal, with his novel “2084: The End of the World,” proves up to the task. A dark, droning fantasy, “2084” depicts a future where state-sponsored ignorance and mindless faith have created a zombie-like society run by a clergy of autocrats. In between idiosyncratic snippets of pseudo-wisdom, a moral of sorts unfolds; a moral that attaches itself to a popular narrative, but one that lends itself to predictability.