“Islands are metaphors of the heart, no matter what poet says otherwise.”

[3] Metaphor, 3.12. Conclusions
Semiotics and the Philosophy of Language (1984)
Context: No algorithm exists for the metaphor, nor can a metaphor be produced by means of a computer's precise instructions, no matter what the volume of organized information to be fed in. The success of a metaphor is a function of the sociocultural format of the interpreting subjects' encyclopedia. In this perspective, metaphors are produced solely on the basis of a rich cultural framework, on the basis, that is, of a universe of content that is already organized into networks of interpretants, which decide (semiotically) the identities and differences of properties. At the same time, content universe, whose format postulates itself not as rigidly hierarchized but, rather, according to Model Q, alone derives from the metaphorical production and interpretation the opportunity to restructure itself into new nodes of similarity and dissimilarity.

New York Journal-American (11 November 1955)

"Quotes", Notebooks

We never do that, do we, being all of us too much poets. We like to talk in parables and in hints and in indirections — whether from diffidence or some other instinct.
" Education by Poetry http://www.en.utexas.edu/amlit/amlitprivate/scans/edbypo.html", speech delivered at Amherst College and subsequently revised for publication in the Amherst Graduates’ Quarterly (February 1931)
General sources

Charles Lamb Specimens of English Dramatic Poets ([1808] 1854) p. 228.
Criticism

"Taboo and Metaphor"
The Dehumanization of Art and Ideas about the Novel (1925)
Context: The metaphor is perhaps one of man's most fruitful potentialities. Its efficacy verges on magic, and it seems a tool for creation which God forgot inside one of His creatures when He made him. All our other faculties keep us within the realm of the real, of what is already there. The most we can do is to combine things or to break them up. The metaphor alone furnishes an escape; between the real things, it lets emerge imaginary reefs, a crop of floating islands. A strange thing, indeed, the existence in man of this mental activity which substitutes one thing for another — from an urge not so much to get at the first as to get rid of the second.

Notes Toward a Supreme Fiction (1942), It Must Be Abstract
Context: p>So poisonousAre the ravishments of truth, so fatal to
The truth itself, the first idea becomes
The hermit in a poet’s metaphors,Who comes and goes and comes and goes all day.</p

"In Warsaw" (1945), trans. Czesŀaw Miŀosz, Robert Hass and Madeline Levine
Rescue (1945)
Context: How can I live in this country
Where the foot knocks against
The unburied bones of kin?
I hear voices, see smiles. I cannot
Write anything; five hands
Seize my pen and order me to write
The story of their lives and deaths.
Was I born to become
a ritual mourner?
I want to sing of festivities,
The greenwood into which Shakespeare
Often took me. Leave
To poets a moment of happiness,
Otherwise your world will perish.

Source: Haunted (2005), Chapter 13, Civil Twilight