Realism and naturalism are arguably very similar but as you take a deeper look they appear different. Realism is defined as an interest tin and emphasis on life as it is. In literature this does not mean that writers copy what they see and hear. It means that they will select from their observations the material suitable for constructing a story that faithfully represents what they have understood. Naturalism is the philosophy which tries to apply scientific reasoning to the world. In literature it extended the tradition of realism, aiming at an even more faithful, unselective representation of reality, a veritable "slice of life," presented without moral judgment. Naturalism differed from realism in its assumption of scientific determinism, which led naturalistic authors to emphasize man's accidental, physiological nature rather than his moral or rational qualities. Individual characters were seen as helpless products of heredity and environment, motivated by strong instinctual drives from within and harassed by social and economic pressures from without.
             Naturalism is a type of "realism" usually characterized by a pessimistic world view. Naturalism is different from realism in two major parts: subject matter and the concept of a naturalistic character. The subject matter deals with those raw and unpleasant experiences which reduce characters to "degrading" behavior in their struggle to survive and is usually part of the middle or lower classes in society. The subject matter of Realism is drawn from "our experience." But the naturalist discovers those qualities in such characters usually associated with the heroic or acts of violence and passion leading to desperate moments and violent death. Characters are conditioned and controlled by environment, heredity, chance, or instinct; but they have compensating humanistic values which affirm their individuality and life - their struggle for life becomes h
             ...