As a Romantic poet, Keats perceived the imagination as a critical authority that intuitively connects with the transcendent, or those things that are beyond the ken of humans. And, through the medium of sympathetic imagination, Keats essayed to become that which he created through his intense identification with the life of what he explains.
In "Ode to a Nightingale," for instance, Keats describes his state as one in which he is between the real world and the ideal realm of the spirit as in Stanza IV, Keats writes,
Away! away! for I will fly to thee,
Not charioted by Bacchus and his pards,
But on the viewless sings of Poesy...
Aready with thee! tender is the night
And haply, the Queen-Moon is on her throne,
Clustered around by all her starry Fays,
In similar fashion, in "Ode to a Grecian Urn," Keats expresses an imaginative interest in the beautiful urn in an emotional mode as he gives expression to the spirit that runs through all things:
O Attic shape! ....
Of marble men and maidens overwrought,...
With forest branches and the trodden weed...
When old age shall this generation waste,
Thou shalt remain, in midst of other woe
....Than ours, a friend to man....
The final message at the end of this poem is suitable only in the rare, and triumphant realm of the aesthetic in which the imagination predominates, "Beauty is truth, Truth beauty."
Likewise, in "Ode to Autumn," Keats imaginatively identifies with the "close bosom-friend of the maturing sun," Autumn:
Who hath not seen thee oft amid thy store?
Sometimes whoever seeks abroad may find
Thee sitting careless on a granary floor....
Thou watchest the last oozings hours by hours.
While Keats personifies inanimate objects, imbuing a spirit coursing through all things, there is a reality, nevertheless, to his poetry as the subjects of these odes are a part of nature or of history. The little nightingale's song does elevate the poet, but at the same time he hovers between the real world and the ideal world of the spirit. Likewise, as the poet contemplates the real Grecian urn, he feels the spirit that runs through all things and is, thus, transcended to a glorified time. And, in "To Autumn," as Keats describes the season in descriptive imagery, the reader experiences the vision of a real natural phenomenon.