Paradox (literature)
Paradox, however, is essential to the structure and being of the poem. In "The Well Wrought Urn" Brooks shows that paradox was so essential to poetic meaning that paradox was almost identical to poetry. According to literary theorist Leroy Searle, Brooks' use of paradox emphasized the indeterminate lines between form and content. "The form of the poem uniquely embodies its meaning," and the language of the poem "affects the reconciliation of opposites or contraries." While irony functions within the poem, paradox often refers to the meaning and structure of the poem and is thus inclusive of irony. This existence of opposites or contraries and the reconciliation thereof is poetry and the meaning of the poem.
Foundations of mathematics
The name ""paradox"" should not be confused with "contradiction". A contradiction in a formal theory is a formal proof of an absurdity inside the theory (such as ), showing that this theory is inconsistent and must be rejected. But a paradox may be either a surprising but true result in a given formal theory, or an informal argument leading to a contradiction, so that a candidate theory, if it is to be formalized, must disallow at least one of its steps; in this case the problem is to find a satisfying theory without contradiction. Both meanings may apply if the formalized version of the argument forms the proof of a surprising truth. For instance, Russell's paradox may be expressed as "there is no set of all sets" (except in some marginal axiomatic set theories).