Stanley Fish, in his essay "How to Recognize a Poem When You See One," is conducting an experiment in practical criticism, in the manner of I. A. Richards, to challenge standard assumption made in literary criticism concerning the nature of poetry. Fish had, in one class, written a list of names of contemporary critics on the blackboard, arranged vertically. It struck him as an interesting experiment to ask the students in his next class, one on seventeenth-century religious poetry, to interpret the list of names as though it were a poem. The students obliged, and created a "reading" of the list that much resembled their reading of the poems they had been studying in the course.
The point of this experiment was to serve as a practical demonstration of a claim that Fish makes in many other essays, that what defines a poem and creates meaning is not something inherent in the text but rather the conventions and expectations generated by interpretive communities. Rather than there being "poems" as existential entities, what constitutes poetry for Fish is a set of interpretive practices.