"The downhill path is easy, come with me an' it please ye,
We shall escape the uphill by never turning back."
She is tired of walking uphill, so she entreats her lover to join her on the opposite path. These two paths represent two different commitment to morality -- loose or devout. Tired of trying to be virtuous, she wants to embrace the easy way in life. Her solution to the punishment for taking the wrong path is that she'll never look back, as if denying her wrongdoing will exempt her from consequence.
"'Oh, what is that in heaven where grey cloud-flakes are seven,
Where blackest clouds hang riven just at the rainy skirt?'
'Oh, that's a meteor sent us, a message dumb, portentous, --
An undeciphered solemn signal of help or hurt.'"
In this exchange, one can see the two world views of the lovers collide. He is in awe of the beauty of the meteor, as if it were some mysterious sign. On the other hand, she dismisses his wonderment. She says it may in fact be a message, but she decides it not worth pondering. While he is contemplative and earnest, she chooses to ignore and treat the meteor as inconsequential. These attitudes are directly reflected to the lovers' positions on taking the downhill path.
"'Oh, what's that in the hollow, so pale I quake to follow?'
'Oh, that's a thin dead body which waits th' eternal term.'"
Yet again, the two lovers clash in this excerpt. He spots a corpse lying in a clearing in the woods and becomes afraid. When she sees it, she again dismisses the importance of the incident. To her, death is as inconsequential as her present life, in which she makes flippant choices. Insensitive to his alarm, she confirms his worst fear in a manner which communicates that she doesn't care whether or not he's upset by seeing a dead person.
"--nay, too late for cost-counting:
This downhill path is easy, but there's no turning back."
Upon a final entreaty by her lover to return, she commits to taking the downhill path. She has a careless attitude, not taking responsibility for her choice. Her words almost indicate that she doesn't believe she has a choice nor will be held accountable for taking the easy path. Finally, she realizes that the path is indeed easy and that probably bodes ill, but she has already made her final decision.
