Elinor Dashwood represents "sense." She is the anchor of her family, possessing a "strength of understanding" and "coolness of judgment." Her restraint is most evident when she learns of Edward Ferrars’s secret engagement to Lucy Steele. Despite her private heartbreak, she maintains social decorum to protect her family and Edward’s reputation. To Elinor, emotions are internal matters; their outward expression must be regulated to preserve social harmony.
In contrast, Marianne Dashwood is the avatar of "sensibility." She is vibrant, musical, and utterly transparent with her feelings. Marianne views Elinor’s composure as coldness, believing that "to prune one’s expressions of feeling" is a form of dishonesty. Her whirlwind romance with the dashing John Willoughby is defined by an abandonment of propriety—she writes him private letters and visits his estate unchaperoned—placing her personal desires above the expectations of 18th-century society. The Consequences of Extremes Sense and Sensibility
Austen uses the sisters’ romantic failures to critique the extremes of their philosophies. Marianne’s unfiltered sensibility nearly destroys her. When Willoughby abandons her for a wealthy heiress, her grief is so indulgent that it leads to a life-threatening illness. Her refusal to exercise "sense" leaves her defenseless against the cruelties of a world driven by money and status. Elinor Dashwood represents "sense