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?
O 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
O 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.