Luminescence—the emission of light without the accompanying generation of heat—was a phenomenon familiar to both poets and natural philosophers in the seventeenth century. Although they had no means of unraveling the chemical or electrical properties that are now understood as the source of this cold light, Robert Boyle's experiments on damp, decaying wood; or Andrew Marvell's wandering Mower whose uncertain steps are illuminated by the “courteous Lights” of “living Lamps,” which we encounter in his poem “The Mower to the Glo-worms”; let alone John Milton's paradox of hellish furnaces whose flames produce “No light, but rather darkness visible” in the opening verses of Paradise Lost, testify to a fascination with the properties of both light and heat—and the possibility that one may exist without the other. Boyle, Marvell, and Milton (along with Montaigne, Francis Bacon, Henry Power, and Izaak Walton) all feature prominently in David Carroll Simon's absorbing, thoughtful, often illuminating, and occasionally infuriating account of what he terms “the observational mood” discovered in what the author himself describes as a “modest sample size” (30) of seventeenth-century (mainly English) writers.

Light without Heat is a book about the absence of energy. It is a book that has little to say about the restless demonic energy we might associate with Milton's fallen angels, say, or the explosive energy that is a product of the harnessing of natural forces (water, wind, gravity), which informed seventeenth-century technologies of power. Political energy, of the kind that erupted in the mid-seventeenth-century wars of the three kingdoms of the British archipelago, is also (by design) absent from Simon's account. Rather, he is engaged in an altogether more nebulous undertaking: the tracing of patterns of careless (an important word for Simon), indifferent, cool observation, which (he argues in a lengthy introduction that is sometimes an overly defensive account of his own literary-critical methodology) can be detected in the “observational mood” of his chosen texts. Simon's “tacking” (33) between the literary and the scientific writings that engage him is suffused with an attention to “nonchalance” (43), “unconcern” (98), “easygoingness” (169), “emotional quiet” (106), and “dreamy inattention” (113). These qualities—a kind of sprezzatura of the observational method that we don't normally seek to uncover in seventeenth-century natural philosophy—are captured by a practice that the author describes as lingering with the “moment” of the “experience of interpretation,” and of letting things “unfold without any regard for the purposes they serve” (17).

The “tacking” between texts and authors—achieving headway by seeming indirection—can produce surprising and even compelling results. The account, for example, of Henry Power's book of microscopical observations, Experimental Philosophy (1664), which is juxtaposed with a careful reading of Marvell's poem “Upon Appleton House,” isolates the philosophical and visual qualities of both texts, culminating in a brilliantly dexterous analysis of insect, animal, and human eyes (159–63). Similarly, the final chapter of the book, devoted to Adam's and Eve's (and the serpent's) “paradisial labor” (169) in Paradise Lost, gives us an intriguing exploration of Miltonic indirection. At his best, then, Simon is a wonderfully acute (and sometimes very witty) reader and interpreter—his description of Milton's serpent, who “drapes himself expansively across the garden; such is the birthright of snakes” (189), manages to convey both the sinister and the seductive quality of Milton's creation, while it also hints at the unraveling of the future (fallen) history of both humans and serpents.

Light without Heat will gain deserving accolades as an innovative study of seventeenth-century literary and scientific writing. But it will also, I suspect, prompt some less generous responses. Some will be irritated by the author's insistence on projecting himself into the forefront of the reader's experience of the book, an insistence that Simon underlines when, in his introductory essay—and drawing attention to his practice of making regular use of the first-person plural (28), a stylistic tic that isn't as unusual these days as he claims—he manages to occlude the rather more intrusive projection of the first-person singular. Others will find the immensely prolix, metatextual endnotes—one of which, a meditation on Heidegger, Derrida, de Man, and (inevitably) Frederic Jameson, manages to drift over almost two pages of text (221–23)—a source of annoyance. But, as an attempt at capturing and describing the shifting moods of reflection and observation that lie at the core of so much seventeenth-century writing, Simon has nevertheless written a deeply thought-provoking book.