Eyal Peretz is a Professor of Comparative Literature who has written books on subjects ranging from Moby Dick to Brian De Palma to Denis Diderot. This is Peretz’s first foray into Leonardo studies, and he is explicitly not writing as an art historian. Messengers of Infinity: On the Pictorial Logic of Leonardo da Vinci purports to be the “first philosophical engagement with the pictorial work of Leonardo, seen as a systematic whole” written from the viewpoint of contemporary continental philosophy and “theories of modern artistic media” (back cover). Peretz’s response to Leonardo’s paintings is a creative contribution to the literature, occasionally far-fetched, but more typically uncannily accurate. Peretz’s introduction characterizes Leonardo as the “first fully formed painter” in Western art, of the “world” understood in its modern phenomenological sense for his “atheological” approach to landscape (8–12). Later, Peretz clarifies that what he has been calling landscape is the Heideggerian “opening of the world without a determined, ordered configuration” (64). The modern [that is, “atheological”] work of art serves as the medium for a new enigma, “a new messenger of infinity” (80–82). Leonardo “trains” our gaze to perform a circular movement between the central “operator” and the other figures dispersed on the pictorial surface so that the eye “participates in the creation of the world and experiences the opening of its own power to see as an ever-renewed event” (92).

Peretz develops his thesis about the “conceptual significance” of Leonardo’s paintings through four chapters, each devoted to one or two of Leonardo’s paintings, arranged in roughly chronological order. He concludes with a short discussion of all the “exceptional figures” in Leonardo’s paintings as “pictorial logic operators” that communicate between visible phenomena and the invisible logos as “messengers of infinity” located on the pictorial surface. They are the centers “around which all the other pictorial elements revolve” as a “nonmetaphysical ground” (91). For Peretz, the demand for pictorial unity governs every aspect of the surface in Leonardo’s case and others that he associates with the condition of modern subjectivity. He is interested in “fascination,” defined as the “experience of being drawn by that which withdraws from us” (1–2). “Immanence” draws us in at the same time that the image withdraws from us. He understands Leonardo’s perspectival pictorial surfaces as geometrically guided corrections of perceptual illusionism (8–9). Leonardo’s paintings explore “the dimension of unity that opens us to a world of appearance” in a “phenomeno-logical” sense where what appears “is the unity at the background of all phenomena, which itself is invisible” (10). What is radically modern is the “a-theological medium” of appearance: Leonardo’s fundamental innovation is the “horizontal openness” of his pictorial surfaces that Peretz associates with the artist’s sfumato technique which introduces a “thorough sense of indeterminacy” in blurring forms and outlines (12).

To indicate briefly the chapter arguments that flesh out his thesis, in the early Annunciation, the spectator is drawn into the depths of the landscape without a definite horizon, “a captivating infinity, a blank indeterminacy” (18). In the Paris version of the Virgin of the Rocks painted a decade later, the angel is standing [actually she is kneeling] at the threshold of the habitable world understood as landscape (32). A decade later, Christ in The Last Supper is depicted as detached, a portal to the landscape visible through the window behind him, which is both external and internal to the viewer’s eyes, inspiring a new mode of looking at the world as an infinite landscape (45–48). In the late Virgin and Child with Saint Anne left unfinished at Leonardo’s death, the landscape and Saint Anne’s face infuse and inform each other creating an “interlace” (Peretz borrows Merleau-Ponty’s phenomenological term) that is simultaneously intimate and yet also external to us, while the symbolic sacrificial lamb becomes a real lamb in the landscape. Thus “metaphysical verticality” is “reterritorialized” (Peretz uses a term created by Deleuze and Guattari) as “the unpredictable infinity of the world,” which is “the most essential task of modern painting” (66–70). Finally, the Mona Lisa is “an enigmatic mirroring device,” an ambiguous face rendered in subtle gradations of sfumato with psychological depth that remains inaccessible, displaying “the mystery of modern subjectivity” immanent to the atmospheric landscape that takes the place of the “old [vertical] theological ground” (80).

How do Peretz’s perceptions square with the historical evidence? With the sole exception of Alexander Nagel’s nuanced meditation on Leonardo’s sfumato (1993), Peretz gives no indication that he consulted specialized studies of Leonardo’s sources and theoretical writings. So it is a credit to his considerable intuition that Peretz’s observations about the artist’s creation of pictorial unity, what he calls the “phenomeno-logical” structure of his pictorial surfaces, can be corroborated in such depth in Leonardo’s lifelong studies of pictorial perspective. Over the three decades that he recorded notes for his book on painting, Leonardo remained committed to the active role of the subject in the process of vision, even after ca. 1490 when he accepted the correct theory of vision based solely on the action of light entering the eye. Leonardo established connections between the viewer and the vanishing point on the horizon (the point at which receding parallel lines viewed in perspective appear to converge, that is, infinity). This reciprocity, which justifies on theoretical and empirical grounds what Peretz calls the “horizontal openness” of his compositions, are key to Leonardo’s reformulation of geometric optics as the nonlinear science of chiaro e scuro responsible for sfumato (a term he rarely used by the way). Leonardo indicated beyond any of his sources how the changing color of air itself over distance could be represented as a geometric progression of color fading into the distance. He called the proportional intervals “gradients” or degrees. As the basis of what Peretz calls “pictorial unity,” Leonardo’s theory of nonlinear geometric perspective supported his instructions to painters to evaluate the changing appearance of light, color, shadow, distance, position, and the other “functions of the eye” through a process of visual judgment. Geometry, that is, proportionality, what Leonardo called “gradients,” governs depictions of visible phenomena. The viewer in the act of beholding participates actively in what Peretz calls the “immanence” of his paintings. When it came to the figures, Leonardo advised paying close attention to the play of reflected colors so that the figures appear enveloped in their surroundings in ways that enhance the beauty of the coloristic composition, true to nature.

Peretz maintains that Leonardo’s paintings dismantle the divisions between the ontological realms of sacred and profane, belonging to neither one. His images serve as “messengers” of an existence beyond the division of religious and secular, and this is different from secularization (12, citing Giorgio Agamben and Jean-Luc Nancy). This is an extraordinary insight to be based on visual evidence alone, but one that can be extensively documented in Leonardo’s notes. However, Peretz’s assumption that “geometry” is universally “atheological” is contradicted by the historical record. For Leonardo and many of his contemporaries, the geometry that underlies appearances is sacred, a divine harmony that actually exists in the world. Leonardo’s understanding of geometry necessitates a slight course correction to Peretz’s powerful insights about the pictorial unity of Leonardo’s paintings. In the final analysis, as discussed below, it strengthens Peretz’s overall argument that Leonardo’s paintings are “nonsecular.” How the empirical and spiritual intersect in Leonardo’s thinking has elicited increasing interest in recent years. The revelation that he owned numerous popular devotional texts, documented in a book list that came to light with the rediscovery of an autograph notebook in 1964 (Madrid Codex II, Ms. 8936, Biblioteca Nacional de España, Madrid), has reopened discussion of Leonardo’s spirituality, pertaining to his interior experience of faith as distinct from formal doctrine. While there is a broad consensus among specialists that Leonardo initially absorbed the terminology of Neoplatonism in his sources but studied geometric optical theory on Aristotelian terms, Leonardo remained committed to the active role of the subject in the process of vision. Optical theory alone does not explain why he retained the notion that the viewing subject is actively involved in the exchange with its object of vision. Leonardo’s insistence on the beholder’s active seeing shares certain assumptions with Christian light metaphysics, especially the Augustinian idea that the act of physical vision is an analogue for spiritual vision, a purifying process leading to a state of grace.

The stakes of this book are high: Peretz’s argument addresses the history of modern painting in general. His stated aim is to understand the shift from medieval sacred images to modern painting, which he refers to Hans Belting’s thesis that there was a medieval era of sacred cult images followed by the modern era of art (2). Belting’s claim (Bild und Kunst, 1990) has been challenged on many grounds, but these controversies do not concern him (93). However, Peretz does not need to rely on Belting’s thesis to make his argument about the stylistic and syntactical differences between Leonardo’s paintings and hierarchically ordered “vertical” sacred representations. When is painting definitively modern anyway? The style of presentation might have changed significantly with the turn to optical naturalism, but sacred subjects naturalistically rendered also operated as cult and devotional images long after the modern function of art as a high-end commodity entered the picture. The history of Leonardo’s paintings and the numerous copies patrons ordered of them attest to their liturgical and devotional function. In my opinion, as important as Belting’s work has been in moving toward a cultural history of art that encompasses theological issues, Peretz’s argument would be stronger without reference to a linear conception of history and periodization based on the visual aspects of images.  Perhaps Peretz’s most original finding, which is valid independently of Belting’s scheme, is the two-pronged claim that Leonardo’s paintings are “nonsecular” even though they are naturalistic, and their naturalism is governed by an invisible geometry.