Realism and naturalism are two literary movements that emerged in the late 19th century, often overlapping but distinct in their approaches. Realism focuses on depicting everyday life and ordinary characters with a truthful representation, while naturalism extends this by emphasizing a more scientific and deterministic view of human behavior, often influenced by heredity and environment. Both movements sought to challenge romantic ideals by portraying life as it truly is, but naturalism often portrays a harsher, more deterministic perspective on existence.