One of the more speculative tales surrounding the Shroud of Turin, which supposedly depicts the face of Jesus Christ, purports that the cloth was actually made by Leonardo da Vinci. The story goes that Leonardo passed off his own image as Christ’s, possibly as an act of hubris or to trick the Catholic Church. The theory has merits. According to traditional belief, Jesus imparted his image to his burial cloth when he was wrapped in it, but radiocarbon testing has dated the fabric to the Middle Ages. Yet dating the image’s genesis even to the 14th century is mystifying. The linen fiber is neither painted nor dyed—how was the image made?

We know that Leonardo, who made his masterpieces in the late 15th century, experimented with aged cloth. We know that he encoded his own face within the Mona Lisa and Salvator Mundi. We know he was fascinated by the anatomical effects of crucifixion. We also know that the optical science underlying photography was more or less understood in Renaissance Europe and during the Arabic Golden Age—Ibn al-Haytham’s Book of Optics had been translated into Latin by the early 13th century—and that alchemists knew its basic chemistry. And really, who other than Leonardo would have been as capable of creating such an enigmatic and technically inexplicable image?

Most art historians and critics attribute the first fixed photograph either to Nicéphore Niépce or Louis-Jacques-Mandé Daguerre, but in his book Photography and Belief, David Levi Strauss writes that if you believe the mysterious face on the cloth is really the work of Leonardo, then the Shroud of Turin is actually the world’s oldest photographic image. Interestingly, Strauss doesn’t say whether he believes the theory, but then his book isn’t a revisionist history of photography. Strauss’s unorthodox understanding of photographs has informed incisive essays on topics from Joseph Bueys’s precognition of 9/11 to torture scenes at Abu Ghraib to the feminist-Marxist Kurdish revolution in Rojava. In Photography and Belief, he sets out to develop a coherent philosophy of why we believe in photographs. Strauss proposes the Leonardo theory as a reason: “Shroud literature is every bit as conspiratorially arcane as JFK-assassination literature, which is also centered on photographic evidence,” he writes. “But both of these groups of literature—the sacred and the secular (religious faith and political power)—reveal much about the nature of image and belief.”

Photography, Strauss argues, may be a relatively new form of technology, but photographs are an ancient form of images. His theory hinges on the fact that photographs overlap with objects the Byzantines called acheiropoieta, medieval Greek for “icons made without hands.” If Leonardo did in fact impart his image onto ancient cloth and substitute his likeness for Christ’s, his proto-photograph would have been considered in Renaissance Italy a “totally magical act.” It would have involved an instance of belief. When photography was officially “invented” in the 19th century, this preexisting system of belief was transferred onto it. Photographs may be a technical form of image-making, but Strauss proposes that our thinking about them is akin to the mental process by which cultures believe in magic. By the time daguerreotypes were introduced in 1839, he writes, “belief in photography had already been around for millennia.”

It’s worth stopping to ask why, in 2021, we need another theory of photography, particularly one that finds its answers in the Middle Ages. For decades, one of the recurring debates in photographic criticism has been whether photographs participate in the “aestheticization of suffering.” Do images of suffering beautify tragedy, making us immune to, or worse, oddly attracted to it, or do they actually increase our empathetic connection? Do photojournalists expose injustice or do they pawn misfortune for money, clout, and adrenaline?

Strauss recounts the debate’s broad strokes through writings by Walter Benjamin, John Berger, Roland Barthes, Susan Sontag, Julia Kristeva, and others. Perhaps the most significant shift occurred when Sontag, who had previously argued that images of violence were “desensitizing,” revised her views in 2004. “To speak of reality becoming a spectacle is a breathtaking provincialism,” she wrote in Regarding the Pain of Others. “It universalizes the viewing habits of a small, educated population living in the rich part of the world, where news has been converted into entertainment.… It assumes that everyone is a spectator. It suggests, perversely, unseriously, that there is no real suffering in the world.”

Still, critics and photographers disagree today about whether we feel real empathy when looking at terrible images or if they make us apathetic toward misery. Strauss’s argument offers a way around these debates by stressing the question of belief. Individual images simply have less power than the systems that generate them, he maintains, and these systems have adapted themselves to take advantage of our inclination to put our trust in photographs. Strauss has long argued that the answer to our crisis of belief in images is, surprisingly, more images. The experience of 9/11 jolted his belief. The architects of the attacks, Strauss wrote in 2003, “tried to turn our extreme attraction to images of violence and catastrophe against us, but they underestimated the extent to which these images have actually supplanted reality for us.” The attacks, which were meant to be proliferated through images, are the most photographed event in history. A decade after they occurred, when Wired interviewed Strauss about the Obama administration’s decision to withhold photographs of torture at Abu Ghraib, he said, “I want more images. In that way, I guess you could say I have gotten what I want, since today’s communications environment makes more and more images available to us all the time.”

Since the start of the 21st century, in Strauss’s telling, global culture has been shifting from an essentially linguistic culture to a predominantly imagistic one—a trend exacerbated in recent years by social media. Strauss believes this move toward an image-based culture is as revolutionary as the transition away from the oral-poetic tradition to a written one that terrified Socrates. When Socrates railed against writing, he was really railing against a new mode of thinking; such a shift, after all, changes everything. Socrates was, in this way at least, a reactionary. Writing won out over the Homeric tradition of oral poetry only one generation later, when Socrates’ student Plato transcribed his dialogues. And while oral cultures remain throughout the world, most are at risk of disappearing if their offerings are not written down.

Strauss doesn’t see us retreating from an imagistic society, and because he loves images (he’s an art critic, after all), he wouldn’t want us to try. Still, he’s cautious about the power photographs have over us, and their ability to bond us to their world, so he argues it’s time to increase our general literacy in images. When Strauss says he wants more images, he means that he wants more kinds of images. He wants artists and photographers to open new pathways and expand our symbolic order, in part because our belief in photographs leaves us vulnerable to abuse, from political propaganda to corporate advertising. After a literacy of images, Strauss wants a literature of images.

Before we can get there, though, we have to go back to the origins of our belief.

A variant of the phrase “seeing is believing” first appeared in 1609, but already it was phrased as a proverb, as received wisdom. Its inspiration was probably the biblical story of doubting Thomas, the Apostle who refused to believe in Christ’s resurrection until he saw the wounds for himself. Strauss writes that the parable “asserts that believing should not be dependent on sight—that believing based on sight is an inferior belief.” When S. Harward wrote, in the 17th century, that “Seeing is leeving” (which means loving and comes from the Anglo-Saxon lief), he inverted Jesus’ counsel and stood behind Thomas’s skeptical belief.

The history that allowed for this inversion is a long one. In the fourth century, the word “image” referred to Christ as the image of God. But Neoplatonist theologians had to reconcile Christian creed with Plato, who argued that images are inferior to original forms—and the church couldn’t devalue a third of its Holy Trinity. A solution came from Saint Augustine, who believed that God’s image resided in the human mind rather than Jesus’ mortal body. The reconciliation of these two antipodal convictions permitted belief in acheiropoieta: seemingly miraculous images, whether manifested from nothing or purely imaginary, became proof of the divine presence of a Christian God. Images were understood to be emanations rather than representations. The idea took hold and is more or less how the Catholic Church reconciled devotional icons with the Ten Commandments’ prohibition of idolatry. Comparatively, Islam quickly distinguished between images in general and images of God, and consequently it continues to proscribe depictions of Allah and Muhammad, which is similar to taboos in the Jewish faith. But the root of this belief explains centuries of varied iconoclasts, from the Protestant Reformation to ISIS: Destroy the image of one’s deity, its emanations, and you destroy one’s ability to believe. Acheiropoieta were the preferred targets for Byzantine iconoclasts.

Strauss spends the last half of his book triangulating three contemporary sources who bolster his theory: Vilém Flusser, a Czech-born philosopher of media who fled the Nazis for Brazil in 1939; Ioan Couliano, a scholar of Renaissance magic who was likely assassinated by Romanian secret police in 1991 after a lecture at the University of Chicago; and Hans Belting, a German art historian known for his studies in Bildwissenschaft, or image-science. The three are united by their understanding of belief as a science of the imaginary.

Strauss draws from Flusser his conviction that the invention of photography was as influential as the invention of writing because both had the potential to fundamentally change the way we think. In Eros and Magic in the Renaissance, Couliano wrote that the Protestant Reformation was not actually the beginning of modern scientific thought but rather an assault on the imagination; using Giordano Bruno’s writing, he argued that Protestants destroyed Catholic icons because they feared worshipers were being bonded inappropriately to earthly images. Belting pushed this forward, arguing in Likeness and Presence that the entire idea of “art” was conceived basically via a dislocation of religious belief among a small entrepreneurial cadre of introspective painters who suddenly found themselves without the Catholic Church for a patron.

The invention of photography provided a useful cover story for this kind of magical thinking. “Seeing is believing” became the mantra of a new medium that claimed its roots in the scientific method. Some, like Benjamin, troubled the premise, noting that photography was associated with devilry from the start. “The human is created in the image of God and God’s image cannot be captured by any man-made machine,” he wrote in 1931. “This is how the philistine notion of ‘art’ enters the stage.” And just like that, a slippage occurred. Photography inherited the magical system of belief that surrounded icons and acheiropoieta. A camera, so it’s said, can only record the reality in front of it, and with this claim toward objectivity, a photograph came to equate total belief in the world a photograph depicts.

Since photography’s earliest days, innumerable writers and photographers have demonstrated that photographs can lie as easily as words. If you place the invention of photography in the 19th century, then one of the very first photographs, Hippolyte Bayard’s 1840 Self Portrait as a Drowned Man, was a lie and a hoax. Knowing this, why would anyone believe what they see?

Strauss revisits this history to show that the long-running debate around photography’s verisimilitude sidesteps a more pertinent point. Under cover of the debates on whether we should believe what photographs show, a kind of “optical consciousness,” to borrow a phrase from Benjamin, has settled in—and we aren’t going to return to an earlier mode of thinking. Strauss wants us to see that we don’t choose to believe in photographs. Rather, we believe in images when they “emanate” or come out of a world that we already believe in. “Belief does not arise from the object of the photograph,” he concludes. “It comes from the subject, from us.” In the end we’ve reached a second proverbial inversion: If belief comes before seeing, then the phrase could be rewritten, “Believing is seeing.”

The consequences of this reversal can’t be overstated. Last year, Strauss published a book titled Co-Illusion: Dispatches From the End of Communication, in which he argues that Donald Trump’s 2016 victory came, in part, from his ability to weaponize images in mass media. Strauss calls this new age of electioneering “iconopolitics” and illustrates that it’s predicated entirely on which side can get more people to believe in its images. The right has proven particularly savvy at this game, as they’ve tapped into an exceptionally conspiratorial subset of the US population and fed them dangerous but compelling images. The GOP traffics in conspiracies—be it voter fraud or promoting QAnon—not necessarily because it believes them but because, for its supporters, they constitute an aesthetic and an identity.

Technical images do the most damage on social media, where they circulate widely, quickly, and without sufficient context. When, in 2014, Strauss said that he wanted access to more images, he probably didn’t envision his wish coming true to this degree. If photographs and technical images are now our primary means of processing information, how does that alter the social contract of a community or even a nation? If we don’t even understand how and why we believe in photographs, how can we fully comprehend the consequences of deepfakes and social media echo chambers?

There’s a way to interpret Photography and Belief as a call to slow images down. Even as we produce more and more images every day—and our methods of communication increasingly rely on them—Strauss’s book, like all good criticism, attempts to carve out space for freedom. His method allows us to look carefully and consider the impact of the status changes on society—an ever more important task given the breakneck pace of today’s media. “Belief in images has become the test case for the social,” he writes. “If we are to believe in the world, we must have images of it.” That includes images of the world as it truly is, but also images of the world as we would like it to be. Or else, if there’s nothing to see here, there’s nothing to believe.