In "a defence of poetry,” shelley suggests that emotions experienced in life are constantly changing. which lines from "mutability” can also be seen as a reflection of this idea? streaking the darkness radiantly! —yet soon night closes round, and they are lost for ever we rest.—a dream has power to poison sleep; we rise.—one wandering thought pollutes the day we feel, conceive or reason, laugh or weep; embrace fond woe, or cast our cares away man’s yesterday may ne’er be like his morrow; nought may endure but mutability.