"Chiasm or chiasmus is an anglicization of the Greek chiasma, which designates an arrangement of two lines crossed like the letter C (chi) and which refers in particular to cross-shaped sticks, to a diagonally arranged bandage, or to a cruciform incision. As a grammatical and rhetorical device, the figure of a chiasm corresponds, basically, to inverted parallelism. In chiasm, the order of words in one of two balancing clauses or phrases is inverted in the other so as to produce its well-known crisscross effect. It is not without interest to note that this figure has received rather negative valorization from the early scholiasts on to the more recent standard handbooks of rhetoric. It is usually considered deliberately contrived and artificial, no more than a practical device. [. . . ] But chiasm, which occurs in great abundance in ancient writing, especially in Near Eastern literature, but in Greek and Latin literature as well, is a decisive ordering principle employed on all levels of complexity, that is, with respect not only to sounds but to thoughts as well. As John W. Welch notes, it "may give structure to the thought pattern and development of entire literary units, as well as to shorter sections whose compostion is more dependent on immediate tones and rhythms." Certainly, where chiasm is predominantly grammatical and rhetorical, its function may be merely ornimental and may amount to an unpretentious play on crossover effects of words and sounds. But in Hebrew and other Oriental literatures, and, as Welch has shown, in the Greek and Latin literary arena as well, chiasmic inversion also rises to much more elaborate levels when it assumes the function of a constructive principle, or structural principle of form. When used as an ordering device of thoughts, the chiasmic reversal is also called hysteron proteron (i.e., the latter first). The grammarians and rhetoricians think in particular of Homer's fondness for having his characters answer plural questions in a reverse order. Welch remarks that "hysteron proteron describes passages wlhich are constructed so that their first thought refers to some latter thought of a preceeding passage, and their latter thought, to some preceeding passage's former thought." Although the hysteron proteron is formally equivalent to the chiasm of formal rhetoric, it is functioally different, insofar as it gives order to ideas, and not merely to words or sounds. As distinct from chiasm--a distinction largely responsible for the relegation of chiasm to a secondary and merely ornamental role--the hysteron proteron is said to serve as principle for creating continuity without the use of transitory particles between multitermed and contrasting passages. The careful ligaturing undertaken by the hysteron proteron in order to achieve unbroken and continuous succession in a narrative , as Samuel E. Bassett has shown, is basically a psychological device, a function of the relation of the (Homeric) poet to his listener, "which assists the narrator to hold the attention of his listener with a minimum of effort on the paret of the latter.: But grammatical, rhetorical, or psychological explanations cannot exhaust the role of the chiasm. Indeed, when employed in order to draw together and connect juxtaposed and emphasized terms in opposition, this ordering form exceeds rhetoric and psychology, or lexis, especially where, as in Heraclitus, it becomes dependent on content. Chiasm, then, is no linger a merely ornamental form or psychological device but, rather, reveals itself as an originary form of thought, of dianoia. Originally, as a form, as the form of thought, chiasm is what allows oppostions to be bound into unity in the first place. It isa form that makes it possible to determine differences with respect to an underlying totality. The chiasm, so to speak, cross-bandages the crosswise incision by which it divided a whole not its proper differences. Emmanuel Levinas, therefore, may rightly speak, "of a pleasure of contact at the heart of the chiasm."

It is in this sense that the chiasm is one of the earliest forms of thought: it alows the drawing apart and bringing together fo opposite functions or terms and entwines them within an identity of movements. In Heraclitus, in particular, the chiasm acquires this role of establishing the unity of opposites. Thanks to the form of chiasm, "that which is in oppsition is in concert, and from thinks that differ comes the most beautiful harmony.: Nothing opposite is left standing in an isolated manner; rather, through the chiasm, opposites are linked into pairs of of parallel and inverted oppositions on the ground of an inverted unity, a tauto, which manifests itself through what is separated. Whether this unity is that of the totality of the universe or that of the singular does not concern us here. On the contrary, what concerns us is the idea that chiasmic reversals secure, by the very moment of the inversion of the link that exists between opposite poles (i.e., thorugh a back-stretched connection), the agreement of a thing at variance with itself."

Rudolphe Gasché, Introduction to Readings In Interpretation: Hölderlin, Hegel, Heidegger, by Andrzej Warminski. p. xvi.