This twinning action found in metaphors, Ong asserts, points to something "at the heart" of all linguistic operations. To understand what happens in a linguistic operation, the intellect must perform its own twinning action, going over a sentence twice to join the subject and the predicate (for example, in the sentence, "This swims," the intellect must first understand what "this" is and then understand what "this" does). Through this twinning process, in which the predicate provides a limiting device for meaning, the intellect gets at the truth of the sentence, which can only be understood for a brief moment before it is lost again.
The problem, however, is that most statements (or enunciations or judgments, as Ong refers to them) do not express the twinning process the intellect goes through; a judgment comes out as a one-sided statement rather than the double-sided idea it is. But metaphors do express the double-sided nature of ideas, especially when the metaphor occurs in the subject rather than the predicate, as is "That cur should not be allowed in office" (rather than in a sentence such as "That man is a cur."). In the first sentence, both "man" and "dog" are implied in the word "cur," but in the second sentence, the impact of both meanings contained in one word is lessened because "man" is mentioned while "dog" is not. In summary, metaphors work as "condensed judgment," in which the one-sided nature of judgment is expressed but so is its two-sided nature.
In order to show how this capturing of one-sidedness and two-sidedness
occurs in literature, Ong examines Shakespeare's poem, The Phoenix and
the Turtle (1601). In this poem, the images of the phoenix and
the turtle offer multiple metaphors for abstract concepts such as birth/death
and love/devotion, the mind and the body, and the Church and Christ.
In addition to these multiple metaphors, there exists a twinning action
in the poem that unifies the images of the phoenix and the turtle and also
becomes a metaphor for metaphor itself: in the end, the human intellect
cannot capture all it wants to express in judgment; instead, it must rely
on metaphor.