In George Eliot's "The Mill on the Floss," the characters navigate the complex transitions from childhood to adulthood. The phrase highlights a poignant realization; once they venture into the complexities of life, the simplicity and innocence of childhood are irrevocably left behind. This metaphor of the "thorny wilderness" symbolizes the difficult and tumultuous journey ahead, contrasting sharply with the golden gates that represent the safety and comfort of their early years.

The closing of those gates signifies not just a physical departure but a significant emotional and psychological shift. The characters must confront the realities of adult life, fraught with challenges and responsibilities that test their resilience and shape their identities. Eliot effectively captures this bittersweet moment, underscoring the inevitable loss of innocence and the daunting path that lies ahead for those growing up.