Final answer:
Paradise Lost employs epic conventions such as invoking a muse, starting in medias res, and a formal style, but ironically merges these with a biblical narrative. Chiasmus is used as a rhetorical device, reflecting internal themes of good and evil that contrast with classical epic focus on external events.
Step-by-step explanation:
Paradise Lost adheres to various epic conventions at its start, such as invoking a muse, starting in medias res (in the middle of things), and beginning with a statement of theme. One of the ironic elements is the use of these classical conventions to tell a biblical story, thus merging pagan traditions with Christian subject matter. Additionally, the epic convention of a high and formal style is employed, but the work itself questions the very hierarchies and values typically reinforced by such a style, as shown through its complex portrayal of characters like Satan.
One particular epic convention used is the chiasmus, a rhetorical device featuring a reversal in the structure of phrases. For example, the line "The mind is its own place, and in itself can make a Heav'n of Hell, a Hell of Heav'n" illustrates this technique. The irony here is that it reflects the poem's theme of free will and the internal struggle between good and evil, while also subverting the typical outwardly-focused subject matter of classical epics.