There are more than one hundred passages which explicitly call upon astronomical learning in Dante's Commedia, from the reference to the sun's position in Aries in the first canto of the Inferno to the repeated astronomical incipits that mark out the passage of time in Purgatorio and onto the heavens and their respective planets which form the backdrop to much of the Paradiso. This wealth of material, much of it forbiddingly technical for the literary scholar, has received centuries of commentary and met with a variety of critical responses in the last 150 years. Some modern astronomers have calculated Dante's references to the heavens against known astronomical data, while several Dantists, both anglophone and Italian, have compiled handbooks in illustration of all the relevant allusions. Dante's astronomy has also received some dismissive commentary, not merely from those influenced by Benedetto Croce's distinction between poesia and non poesia, but also from readers and commentators who view Dante's recurrent recourse to astronomy as no more than erudite, and somewhat otiose, embellishment. Cornish's outstanding book places all these earlier efforts within a new dimension by constantly illuminating the moral and interpretative dynamics that underlie Dante's use of the stars. And in so doing her study emerges as the most important critical study of Dante's astronomy to date:
The task at hand is not to collect and explicate examples of Dante's use of astronomy, as the handbooks do so well, but rather to demonstrate how specific astronomical references illustrate, support, or dramatize the poetic, moral, theological, or philosophical problems at issue in the context in which they appear, and how they provide visual parallels to the strategy of representation currently at work. (3)
Within these terms, Dante's stars are viewed as a "hermeneutic challenge", as "paragons or models of reading" which call out for both interpretation and the ethical responsibility instilled into the task of reading by medieval culture. This framework underpins all of the chapters in the book as Cornish examines the date of Dante's journey and his deployment of astronomy in all three cantiche of the poem.
Chapter 1 ("The Allure of the Stars: Vita nuova, Convivio, Commedia") explores the prominent role of the celestial spheres in Dante's earlier works and the Commedia with reference to their links with erotic desire and the philosophical quest. Cornish is particularly acute in drawing out the cosmological erotics in Dante's presentation of Beatrice in the Vita nuova, showing how her identification with the heavens and celestial motion through the number nine brings with it a further linkage with love (love is the principle of movement tending towards a beloved end). In the Convivio the astronomical order becomes a template for the organization of knowledge, while both the erotic and the intellectual are foregrounded by the links between the heavens and Beatrice (both are deficient but nonetheless fundamental stages in the quest for divine truths) in the Commedia.
Chapter 2 ("The Date of the Journey") is the most accomplished in the book and the most representative of Cornish's general approach and critical method. It focuses upon the significance of the year 1300 and the apparent inconsistency between Dante's references and the actual astronomical situation of that year. Rather than indulging in a minute examination of all earlier interpretations, this chapter expands upon the elegant and incisive point that "all dates, and most especially the date of Easter with which Dante's narrative is connected, are always artful reconciliations of the apparently divergent threads of reality". (29) Setting the first time-reference against not merely astronomical data, but, more importantly, a rich background of paschal symbolism and chronometry (35-9), Cornish illustrates the "wholly fictional and conciliatory nature of Dante's skies" and the "patently false astronomical description of spring at the start of the poem". (34) Astronomy is manipulated to create a fiction that not only has the weight of popular imagination, but also participates in a rich background of religious symbolism against which fictions are seen as "an imitation of the larger fiction of Easter's sacramental commemoration". (41) There is here a rare and highly judicious awareness that we cannot simply measure what Dante is doing with astronomy (and the point applies equally well for other branches of medieval science) by the terms of reference of that science alone. In this way Cornish confirms earlier suggestions in J. D. North's Chaucer's Stars (a work which surprisingly Cornish does not cite) that Dante's astronomical periphrases do not lend themselves to methods of careful calculation of heavenly configurations.
Chapter 3 ("The Harvest of Reading: (Inferno 20, 24, 26)") provides an interesting reading of three passages where star-gazing farmers are inserted within the narrative and help to underline "the status of the Commedia's astronomy as fruitful reading material". (43) The first, a diviner from Lucan, is juxtaposed by Dante with a simple Carrarese peasant, and reveals the farmer as "a fruitful reader of stars in contrast with immoderate seekers of hidden things". (49) The next passage, the opening simile of canto 24, is read as providing a critique of Virgil, suggesting that the farmer who figures in the comparison is superior to the poet of farming (Virgil of the Georgics) because he reads the signs of nature hopefully. The final farmer, the "villano" presented in another simile from canto 26, is also interpreted as a figure of hope analogous to the "agricola" in the Epistle of James. All three figures constitute a critique of the classical world and present astronomical knowledge "under the humblest possible aspect, exalting the farmer as a fruitful reader of the stars, of which Hell's damned have totally lost sight". (60)
Chapter 4 ("Orientation: Purgatorio 9") considers the multiple time-references of Purgatorio as a utopian gesture, by which Dante invites us to see the corrective world of Purgatory within our own present state. In this vein, the chapter shows how astronomical time-references are involved in a fundamental strategy of allegorical comparison. The chapter is especially useful on the multiple chronometers of Purgatory (Dante, souls, various points on the global dial) as well as for its emphasis that time is dependent upon the relative position of observer. Once again, the point is made that astronomical time-references are not gratuitous displays of erudition but moments of heightened reader engagement where attention is called to his/her own geographical context. In this light, Cornish examines one of the most ambiguous technical passages in the entire poem, Purgatorio 9, 1- 12, noting how it is suffused with the pathos of temporal distance and reinterpreting it on the basis of double time- reference: multiple chronometers are in short "a constant reminder that the alternation of dark and light is merely the impression of an individual bound to any one particular terrestrial location in a cosmos that is in reality wholly flooded with light". (76)
Chapter 5 ("Losing the Meridian: From Purgatorio to Paradiso") starts from the premise that Dante uses different representational strategies in each cantica and examines the impact of such shifts in poetic strategy on the way in which celestial bodies and their movements are used in the Paradiso. Cornish notes the high density of astronomical comparison in the allegorical pageants of Earthly Paradise, and in the final cantica astronomical imagery becomes, she argues, detached from the setting of the story to be invoked as similitudes for an indescribable vision: "dazzling but still inadequate substitutes for invisible truths". (92) To lose the meridian (cf. Purg. XXXIII, 103-05) is to lose the fictional conventions by which we tell time. This is an interesting and well-illustrated point even though the reliance upon F. X. Newman's notion of a shift in representational strategy from one cantica to another leads to some neglect of astronomical imagery that is used literally and not by analogy.
The remaining three chapters in the book discuss the significance of three separate sequences in the Paradiso that involve astronomical imagery and concepts. Chapter 6 ("The Shadow of Ideas: Paradiso 13") examines the opening astronomical simile in Paradiso 13 and advances an important and original interpretation of its function as offering the reader a mental exercise in mnemonic reconstruction which has as its goal the pursuit of wisdom. Chapter 7 ("The Sufficient Example: Paradiso 28") illustrates, again through pertinent quotation from medieval sources, how astronomical principles govern the responses of Dante the protagonist to his vision of nine circles surrounding a point of light in this canto. Chapter 8 ("Planets and Angels: Paradiso 29") examines the paradoxes involved in the canto's opening simile, revealing how it mimics the paradox of creation and sin so as to provide "a poetic representation of the enigmatic exordium of the universe". (122) In order to contextualize the passage, there is a detailed (but in a book so notable for its concision perhaps overly extended) discussion of the creation and fall of the angels (129-36).
Throughout the volume, Cornish's arguments are supported by considerable expertise in the handling of primary source- material, not only ancient and medieval astronomical texts, but also many highly pertinent passages from an array of other authorities classical, patristic, Platonist, encyclopaedic, scholastic, and vernacular. The only authority that might have been invoked more fully is Restoro d'Arezzo, whose La composizione del mondo colle sue cascioni (only mentioned once and in an outmoded edition, p. 166, n. 40) contains much astronomical material and descriptions that would further support many of the points made by Cornish. The endnotes are rich and detailed and give the full Latin text of passages translated or alluded to in the main text. In the notes there are occasional misprints (p. 182, n. 24: Baranski; p. 189, n. 7: Barbera is not the editor of Benvenuto's Comentum) and a few inconsistencies (e.g. Macrobius also appears once as Macrobio; Croce is cited from the original 1921 edition as well as from a later reprint).
Concise, elegant, and learned, Cornish has performed a great service to students of Dante and medieval astronomy and one can only hope that her critical methodology will influence future studies of the place of medieval scientific learning in Dante's texts and that her interpretations and related contextual material will find their way into future commentaries on the Commedia.