If 1991's Defending Your Life is the gold standard of its time for films dealing with the subject of existential fear, then 1951's The Day The Earth Stood Still is the gold standard of its time for the same. Both films present fear as humanity's defining challenge, but from opposite vantage points: Klaatu observes our fear from the enlightened perspective of an advanced civilization, while Brooks examines it from the all-too-human position of a man who never quite managed to overcome his. Together, they bookend a forty-year conversation about whether reason can triumph over our most primal instinct.