Debate
Milton uses “Il Penseroso” and "L'Allegro" to make two specific arguments, and also to explore what it means to make an argument in the first place. Together, the poems model the speeches students were taught to make at Cambridge, where they proved their ability in rhetoric by arguing both sides of a debate. By setting two arguments against each other, Milton drains both speeches of their ammunition and makes a broader statement about debate. More than his poems are trying to convince you to lead one life or the other, they’re demonstrating how a good speechmaker operates, how someone can blind you with rhetoric.
Self-Development
Scholars who argue that "L'Allegro" and "Il Penseroso" chart the story of one person progressing from youth to old age have pointed out that the speaker in “Il Penseroso” is more aware of himself than the speaker in “L’Allegro." The speaker in "L'Allegro" mentions himself so infrequently that it’s often difficult to figure out where he fits into the scenes he describes. The speaker in “Il Penseroso,” by contrast, returns to his position in the world again and again. The implication is that the life of contemplation leads you to a more concrete sense of self, a better-developed point of view.
Solitude and Companionship
Unlike the speaker in “L’Allegro,” the speaker in “Il Penseroso" is always alone. It’s only in the final lines of the poem, when music flows from a church, that he finds companions, and even then we don’t see actual people: we only know they are there from the music. If the speaker in “Il Penseroso” has relationships, they’re with the people he encounters in the books he reads every day. His poem is full of allusions to characters from literature. Where the speaker in “L’Allegro” describes meeting shepherds, the speaker in “Il Penseroso” instead alludes to stories from classical mythology and poetry. His poem is peopled by books.
