Poet Percy Shelley's quote, "Man's yesterday may ne'er be like his morrow; Nought may endure but Mutability," emphasizes that change is the only constant. Written during a period of political upheaval, Shelley's words suggest human lives and circumstances are always in flux. The quote, featured in Mary Shelley's Frankenstein, offers reassurance by framing mutability as a universal law, encouraging adaptability and resilience in a world defined by constant change.