As Stephen listens to his legs moving through space on the beach he recalls two compound words from a work of aesthetics written in 1766 by the poet, playwright, critic, and philosopher Gotthold Lessing. Laocoon opposes the ekphrastic tradition of comparing poetry to painting, arguing instead that the two arts involve very different modes of sensory apprehension. Poetry presents things "nacheinander" (after-one-another), while painting presents them "nebeneinander" (next-to-one-another).
Gifford quotes from Edward Allen McCormick's 1962 American translation: "In the one case the action is visible and progressive, its different parts occurring one after the other (nacheinander) in a sequence of time, and in the other the action is visible and stationary, its different parts developing in co-existence (nebeneinander) in space." Poetry is an art of moving through time. Painting is an art of positioning things in space.
In some of his aesthetic theorizing in the last chapter of A Portrait of the Artist as a Young Man, Stephen had distinguished between spatial and temporal arts: "An esthetic image is presented to us either in space or in time. What is audible is presented in time, what is visible is presented in space." But rather than further differentiating the two kinds of art in that speech, he analyzed the "esthetic image" in general, applying several aesthetic terms from Aquinas to define it in general formalist terms.
In Proteus, he thinks of Lessing's two terms to conceive of two different modes of apprehension, the "ineluctable modality of the visible" and the "ineluctable modality of the audible." But he shows none of Lessing's interest in separating the two modes and assigning them to different arts. Listening to his feet drumming out a beat "Five, six: the nacheinander," he thinks also of them "at the ends of his legs, nebeneinander." He is involved in both modalities simultaneously and inextricably, traversing "A very short space of time through very short times of space."
Ulysses will explore in revolutionary ways this intersection of spatial and temporal modalities. Drawing on modes of apprehension associated with photography, cinema, statuary, music, poetry, drama, and cartography, it offers an expansive vision of the possibilities of literary art. As Stephen says in A Portrait, just after his Aquinian analysis, "Lessing . . . should not have taken a group of statues to write of. That art, being inferior, does not present the forms I spoke of distinguished clearly from one another."
The allusion to Lessing's work was first noticed by Fritz Senn in an article titled "Esthetic Theories," in JJQ 2.2: 134-36.