We know what we are but know not what we may be. — William Shakespeare

Shakespeare, William. "Hamlet." The Norton Shakespeare, edited by Stephen Greenblatt, et al., 3rd ed., W. W. Norton & Company, 2015, act 4, sc. 5.

Shakespeare, William. "Hamlet." Mr. William Shakespeare's Comedies, Histories, & Tragedies. London: Edward Blount and William and Isaac Jaggard, 1623, act 4, sc. 5.