Final answer:
The lovers' happiness on the urn in Keats's 'Ode on a Grecian Urn' is eternal in the sense that the art will never change, but it is an idealized form of love and happiness. Cleanth Brooks interprets the final lines of the poem as a paradox involving the relationship between beauty and truth within the realm of poetry.
Step-by-step explanation:
In John Keats's poem Ode on a Grecian Urn, the love and the happiness of the lovers depicted on the urn are indeed eternal. This is because they are frozen in time; the images on the urn will always show the lovers in the same perpetual moment, never ageing or changing. The urn, as described by Keats, serves as a sylvan historian, telling a story of eternal beauty and unending happiness through its unchanging art.
However, it's important to note that the love and happiness are eternal only in the artistic sense. The figures on the urn will never consummate their love, thus their happiness is an idealized form, which also implies that they will never experience the progression or conclusion of natural human experiences.
Cleanth Brooks challenges T. S. Eliot's reading of the poem, particularly regarding the famous last lines "Beauty is truth, truth beauty." Eliot saw these words as a disruption to the poem, whereas Brooks saw them as central to the poem's paradox concerning the relationship between a poem's beauty and its truth. Keats's philosophical meditation on art and experience is encapsulated in those closing lines, which suggest that the artistic representation is itself a form of truth.