«Or whether doth my mind, being crown’d with you,
Drink up the monarch’s plague, this flattery?».
Continuing the dichotomy between the eye and the mind, the poet presents two alternative possibilities — indicated by the phrase “Or whether” — for how the eye and mind work.
Or whether doth my mind, being crown’d with you,
Either the mind controls the poet’s seeing and is susceptible to flattery, or his eye is the master of his mind and makes “monsters and things indigest / Such cherubins” that resemble the youth. The poet decides on the first possibility, that his mind controls his sight; whatever the eye sees and whatever comparisons it makes, his mind transforms any object in the best light of the youth. The poet’s eye “well knows” what is agreeing to the poet’s mind “And to his [the mind’s] palate doth prepare the cup.”
Ironically, the poet acknowledges that comparing everything to the youth is unwise, for then he never truly judges either the youth or the world. However, he accepts the risk, for in the sonnet’s final two lines he says that even if his mind is deceiving itself, at least the beautiful appearance of the youth is consolation for this self-deception. In other words, the poet does not care if something is poisoned so long as it is beautiful; appearance is more important than substance.
English audio from YouTube Channel Socratica
Summary from Cliffsnotes.com