Wordsworth's speaker in "To a Butterfly" is unsure whether the butterfly he has been gazing at for half an hour is asleep or feeding. His confusion arises because the butterfly is so very still. The speaker is so impressed by the butterfly's stillness that he reinforces his sense of awe by repeating twice how "motionless" the butterfly is:
How motionless! . . .
He also does this by using exclamation points to add emphasis and to convey emotion.
Wordsworth has his speaker directly address the butterfly while also engaging in some classically Wordsworthian moves. Wordsworth was fascinated by the way nature, because it is unchanging, becomes a backdrop against which humans can measure personal growth. Although he points to the butterfly's stillness, the insect's stillness is only made possible because the mature Wordsworth is capable of sitting still and observing it for a long period. He contrasts this to his boyish ways of chasing butterflies, but he also appreciates the presence of the butterfly in his garden for bringing back happy memories of bygone childhood days.