The sententious statement attributed to the urn at the close of the poem is similar to a remark made by Keats in his Letters: 'What the Imagination seizes as Beauty must be truth', and the idea of the interdependence of Beauty, Truth and Imagination is something that figures repeatedly in Keats. In 'Grecian Urn', Keats arrives at the statement through the series of paradoxes of eternity and transience that he develops throughout the poem. Yet, far from being an unequivocal conclusion that resolves all the paradoxes, the closing statement creates whole new questions.
We cannot be certain, for example, on who is saying what to whom. The speech marks that enclose the Urn's statement have been placed variously by different editors. To see the alternatives, you need to look closely at the last three lines. In some versions, the inverted commas enclose just 'Beauty is truth, truth beauty'. So the possibilities are:
1 - The Urn 'speaks' the statement about Beauty and Truth; and 'that is all..' is spoken by Keats to the reader;
2 - The last two lines complete are spoken by the Urn to humankind;
3 - The last three lines complete are spoken by Keats to the Urn.
It's dizzying, but wonderful, and it makes a real difference to the way we respond to the poem, and the idea of Beauty embodied in the Urn. In the end, it seems that the Urn is beautiful, but reminds us simultaneously that true Beauty is not frozen and eternal, but subject to Time and Change.
Aspects of life are frozen on the urn in different images which chronicle a ritual of another culture in another time. It represents, for that people, an aspect of life that had meaning. It therefore contains a truth for the Greek people who are depicted, and for those who look at the urn.
The beauty of the urn draws up in, as one examines its detailed representations of nature and life gone by, it connects the observer to the past. All peoples are linked together through the urn's timeless beauty. It expresses an absolute truth, giving meaning to human existence.
"When old age shall this generation waste,
Thou shalt remain, in midst of other woe
Than ours, a friend to man, to whom thou say'st,
"Beauty is truth, truth beauty," - that is all
Ye know on earth, and all ye need to know"
Therefore, the urn will always be available, long after we are gone, to represent life, beauty and truth in its timeless images. Art, its beauty, exists in its preservation of the past in a snapshot carefully preserved for all time.
"One way of looking at the "truth and beauty" statement is to consider that the scene on the urn is true and beautiful because it is self-contained: it has no need for answers, and so it will always have found its truth,"