Keats' theory of "negative capability" was expressed in his letter to his brothers dated Sunday, 21 December 1817. He says 
I had not a dispute but a disquisition with Dilke, on various subjects; several things dovetailed in my mind, & at once it struck me, what quality went to form a Man of Achievement especially in literature & which Shakespeare possessed so enormously - I mean Negative Capability, that is when man is capable of being in uncertainties, Mysteries, doubts without any irritable reaching after fact & reason - Coleridge, for instance, would let go by a fine isolated verisimilitude caught from the Penetralium of mystery, from being incapable of remaining content with half knowledge. This pursued through Volumes would perhaps take us no further than this, that with a great poet the sense of Beauty overcomes every other consideration, or rather obliterates all consideration.
Keats believed that great people (especially poets) have the ability to accept that not everything can be resolved. Keats, as a Romantic, believed that the truths found in the imagination access holy authority. Such authority cannot otherwise be understood, and thus he writes of "uncertainties." This "being in uncertaint[y]" is a place between the mundane, ready reality and the multiple potentials of a more fully understood existence. It relates to his metaphor of the Mansion of Many Apartments.
It could be argued that Keats explored this idea in several of his poems
- La Belle Dame sans Merci: A Ballad (1819)
- Ode to a Nightingale (1819)
- The Fall of Hyperion: A Dream (1819)
- Ode on a Grecian Urn (1819)
positive Template:Clarify capability is a state of intentional open-mindedness paralleled in the literary and philosophic stances of other writers. In the 1930s, the American philosopher John Dewey cited Keatsian negative capability as having influenced his own philosophical pragmatism, and said of Keats' letter that it "contains more of the psychology of productive thought than many treatises."  Nathan Scott, in his book Negative capability; studies in the new literature and the religious situation, notes that negative capability has been compared to Heidegger’s concept of Gelassenheit, “the spirit of disponibilité before What-Is which permits us simply to let things be in whatever may be their uncertainty and their mystery." Walter Jackson Bate, Keats's biographer, explored the approach in detail in his 1968 work Negative Capability: The Intuitive Approach in Keats.
It is important to note, however, that Keats did not theorise upon "Negative Capability" at great length. In fact, this phrase, like many of his other famous ideas - the Chameleon Poet, the Vale of Soul-making, the Mansion of Many Apartments - appears only once in all his correspondence. The fact that these theories were never formally cemented, but emerged in the flow of single, specific letters, is highly relevant to Keats's own conception of them. However, the general meaning of Negative Capability has been fixed by its subsequent discussion.
- Jacob D. Wigod, "Negative Capability and Wise Passiveness," PMLA, vol. 67, no. 4. (June 1952), pp. 383–90.
- ↑ Romanticism: an anthology, By Duncan Wu, Duncan Wu Edition: 3, illustrated Published by Blackwell, 2005 p.1351
- ↑ Dewey, John. Art as Experience. New York: Penguin Perigree (2005):33-4.
- ↑ Kestenbaum, Victor. The Grace and the Severity of the Ideal: John Dewey and the Transcendent. Chicago: University of Chicago Press (2002): 225.
- ↑ Scott Negative capability; studies in the new literature and the religious situationYale University Press (New Haven), 1969
- ↑ Scott, Grant (ed.), Selected Letters of John Keats, Harvard University Press (2002)