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  • When the Eyes Are Shut: The Strange Case of Girolamo Cardano’s Idolum in Somniorum Synesiorum Libri IIII (1562)

In his treatise on dreams Somniorum Synesiorum Libri IIII, published in 1562, the Italian Renaissance philosopher and physician Girolamo Cardano distinguishes between idola and visiones (or visa). Historians have discussed the reasons for such a distinction without taking into account Cardano’s original theory of sense-perception. In this article I shall argue that, in order to interpret the meaning of idola and visiones in Cardano’s theory of dreams, one should bear in mind his view that hearing is superior to sight and that while idola are essentially based on sound, visiones depend on images.


Girolamo Cardano, Synesius of Cyrene, Idolum, Hearing and sight, Renaissance theories of dreams


In Athens, Still Remains, a philosophical essay on a collection of photographs of contemporary Athens by Jean-François Bonhomme, the twentieth-century French philosopher Jacques Derrida describes the relationship between photographs and their subject matter as an experience of mourning, which bears the grief for what is lost between the moment of the object—or the person—in front of the camera and the snapshot: “But each one of them [the photographs] remains in its turn what it becomes: a funerary inscription with a proper name. Having to keep what it loses, namely the departed, does not every photograph act in effect through the bereaved experience of such a proper name, through the irresistible singularity of its referent, its here-now, its date? And thus through the irresistible singularity of its rapport with or relation to what it shows, its ferance or its bearing, the portée that constitutes its proper visibility?”1

A photograph, for Derrida, is always an image of absence, of the discrepancy between the reality and the representation of the photographed, [End Page 179] and finds its raison d’être in the separation and distance from what it represents. The true being of all images, after all, is their not-being. They are never one with what they offer to the human eyes; they are mere representations of the visibility of what is no longer there. This unique ontological status of images—which do not exist per se, but as a reflection of something else—inspired writers, poets and philosophers long before Derrida. In the history of Western thought, in particular, the fascination prompted by the tenuous nature of images can be traced back to the ancient Greek world, where the difference between reality and appearance had an important speculative relevance, which informed literary works and philosophical debates. The theoretical potential of images is encapsulated in the ancient Greek word eidôlon, which covered a broad conceptual domain: from representations of reality (the products of the imaginative activity and of dreams) to apparitions (especially those of the souls of the dead) to shadows and reflections.2 Eidôla was Homer’s word for the shades met by Odysseus in the underworld, outlines of the persons he used to know. In the sixth century BC, the poet Stesichorus wrote that it was the eidôlon of Helen that went to Troy with Paris while the woman herself stayed in Egypt.3 The consequences of this post-Homeric revision of the myth—furthered by other writers such as Euripides and Aristophanes—have been far-reaching, since it implied that the Trojan War was fought not for a woman, but for her ghost, her shadow or image.

Within the philosophical field, for the fifth-century atomists, eidôla were effluences given off by solid bodies and impressing the sense organs with representations of those bodies. All cognitive processes, from sense perception to the activity of the intellect, depended on such material particles flowing from the outside world to the perceiving subject. In his Letter to Herodotus, Epicurus had described eidôla as outlines or effluvia which have the same shape as solid bodies, but are much thinner than any other [End Page 180] object we see.4 The stream of thin images into the eyes and mind has a central part also in Lucretius’s discussion of the mechanism of visual perceptions and of dreams. Translating Epicurus’s eidôla as rerum simulacra (images of things), Lucretius claims that vision is possible through such simulacra, which convey to the immaterial mind a dematerialized copy of the material object. Like a “sort of skin shed from the surface of objects, from the outer layer” or “films that drift about this way and that upon the air,”5 they establish an unseen material connection between the mind and the objects of visual perception.

In Plato’s philosophy, eidôla occupied a liminal region between Being and Not-Being and supplied a metaphysical alternative to Parmenides’s radical separation of Not-Being from the class of entities that were said to have a real existence, for eidôla were forms of unreality blended with reality.6 They were illusory projections of the real being of intelligible forms. In the Sophist, Theaetetus explains to the Stranger of Elea that eidôla are not things in themselves, yet they bear the resemblance of things. Like “images in water and in mirrors, and those in paintings, too, and sculptures, and all the other things of the same sort,”7 they do not really “exist,” but are only likenesses.8 As Plato would have it, images exist in the material world, but their existence is to be considered metaphysically unreal.9 For him, an eidôlon is not an object of intellection, but of sense perception. It belongs to the realm of illusions and delusions and is an important instrument in the deceptive art of the sophistic imitation. The term itself, as Peter T. Struck has observed, “marks the conjuration of spirits, ghosts and phantoms.”10

In the context of Platonic interpretation of dreams and visions, eidôla found a special place in the treatise On Dreams written in the fifth century AD by the philosopher Synesius of Cyrene, which proved to be highly influential for later theories of dream interpretation. Synesius was the first [End Page 181] to connect eidôla and dreams, by combining the atomistic theory of effluvia with the Neoplatonic doctrine of the “vehicle of the soul.”11 The vehicle of the soul, called ochêma in Greek, was regarded as a semi-material envelope that the soul acquired in its descent through the spheres and that acted as the organ of sense perception and imagination, the pneumatic substrate on which images were impressed and retained. Synesius and his fellow Platonists believed that there was an ontological similarity between the images constantly being realized from objects and the vehicle of the soul, also called pneuma by Synesius, as both were composed of the same spiritual matter. Such similarity of nature allowed the soul to perceive the external world. Processes of perception and dreams were made possible by the existence of this intermediate dimension between the material and the intelligible worlds, in which the images conveying the accidents of external objects could meet the lower part of the soul, understood as a sort of wax tablet. For this reason, in order for the soul to be able to communicate with the gods and have prophetic dreams, it was of the utmost importance to keep the pneuma pure from material affections. Whereas during the day corporeal influences made the pneuma thick and opaque, during sleep—when sense-perception and bodily functions are less active—it was thought to become translucent and able to have visions of the future. When the pneuma is undefiled, Synesius believed, it is “no longer a stranger to the soul”12 and becomes ready to receive the gifts bestowed upon it by God, including prophetic dreams. Before learning the art of divination by dreams, it is therefore necessary to learn how to resist the enticement of material images. “This science of divination I desire to possess and bequeath to my children,” Synesius writes. A science that does not require “a painful journey, nor a long voyage, to go to Delphos or into the desert of Ammon.”13 Just as Penelope took a bath in pure water before invoking Minerva and “covered her body with a veil of dazzling whiteness,” we [End Page 182] should “make ablutions and a prayer” before going to bed.14 In this way sleep, a natural necessity, “becomes a source of enjoyment and we do not sleep merely to live, but to learn to live well.”15 Not only was the cleanliness of the pneuma fundamental to keeping the soul connected to God day and night, it was also important for the fate of the soul after death, which could be rather bizarre. The pneuma that was unable to resist the attraction of material eidôla would in the afterlife itself become an eidôlon, that is, a dematerialized version of the person it had been on earth.16 Unlike Porphyry before him, who regarded the eidôlon as a separate body dragged along by the soul,17 for Synesius the eidolôn was the soul itself in the process of being purified from all the images perceived during its embodied life.18 The closer the soul kept itself to matter, the stronger its eidolic nature became. In its theory of knowledge or of dreams, Platonic philosophy had strengthened the idea of the eidôlon as a deceptive image concealing the true nature of things: eidôla were uncanny presences that belonged to Hades or to the world of shadows and prevented men from contemplating the intelligible light.

Even beyond Platonism, though, and notwithstanding contextual differences, Western thought regarded eidôla as visual perceptions of the doubles of persons or things. In the underworld or on earth, in theories of dreams or of knowledge, eidôla were images, that is, objects of vision. However, in Girolamo Cardano’s Somniorum Synesiorum Libri IIII, published in 1562 and inspired by Synesius’s treatise, eidôla—idola in Cardano’s Latin—lose their traditional status as images and become sounds, leaving the domain of sight for that of hearing. This peculiar—and to my knowledge unique—concept of “heard vision” in the Renaissance brings together the lexical reference to the eyes nested in the word eidôlon, which derives from the verb eidein, to see, and the act of perceiving sounds. This collision of visual and auditory sensory perceptions appears even more peculiar if one considers that it is contained in an important treatise on dreams and that common sense has always identified dreams with visual contents. Moreover, for Cardano the idolum is not a source of deception, for it represents the very reality beyond the appearances of things. [End Page 183]


Girolamo Cardano began to write his Somniorum Synesiorum Libri around 1545.19 Originally the work was in ten books and then revised and enlarged until the definitive version in four books was published in Basel in 1562. It was translated the following year into German. The original Latin was included in his Opera omnia, published in Lyon in 1663.20 Dreams always served as omens of crucial moments in Cardano’s own life, such as the death of his son Giovanni Battista or the writing of important works. His decision to devote a treatise to divination through dreams may have resulted from his willingness to give a scientific account of the relationship between his own dreams and significant events in his life. Cardano’s choice to write on dreams following the treatise of Synesius, moreover, reveals that his work is concerned mainly with prophetic dreams, which are caused by divine influence and flow into the soul when it has discarded every thought and is free from corporeal affections. Dreams of divine origin, however, are not for everybody and happen only on rare occasions. Far more common are dreams of natural origin, which can be trigged by the dreamer’s psychological state, by his memories, by corporeal causes such as bodily humors and heavy meals—the less appropriate for supper being octopus heads, cabbage, onions, broad beans, and all those foods that reach the head and produce black bile.21 They are important for the physician, as they can be symptoms of a psychological and physiological imbalance, but have nothing interesting to say to the philosopher or to the wise man. Cardano’s [End Page 184] approach can therefore be defined as “Synesian” because he is interested only in those dreams that evoke the future and unveil the link between natural phenomena and intelligible realities.22

Cardano divides dreams (somnia or insomnia) into two main groups according to their level of clarity: heightened perceptions (idola) and dream-images (visa or visiones). Idola, he explains, are clear and self-evident, do not require interpretation, and provide glimpses of the divine world, invisible to human eyes. They have very little of the dreamlike nature of the images produced by the mind during sleep. Ultimately, as we shall see, they are not dreams at all. Visa or visiones, by contrast, are dreams that result from the transposition and overlapping of different images, and interpretation is necessary in order to grasp their hidden meaning: “Regarding those dreams [somnia] that inform us about hidden things, some of them show these things directly and are called heightened perceptions [idola]; others, however, require an interpretative technique and are called dreams [insomnia] or dream-images [visa].”23

Cardano uses the word insomnium only when he refers to visa or visiones. Idola are not considered insomnia in the strict sense. The word insomnium had a specific meaning in the tradition of dream interpretation, as it is calqued on the Greek enhypnion, i.e., a dream caused by the dreamer’s physical and psychological state. Cardano was well read in medieval as well as in ancient philosophy and one can safely assume that his dream theory was influenced, to a certain degree, also by medieval Latin sources. Thirteenth- and fourteenth-century authors, in particular, who turned to Aristotle’s dream theory and described dreaming as a complex experience involving both physiological processes and divine intervention, might have had a special role in the shaping of his oneiromancy.24 However, Cardano’s linguistic choices and his classification of dreams were more directly inspired by two key texts in the history of dream interpretation, namely, Artemidorus Daldianus’s Oneirocritica (second century AD) and Macrobius’s Commentary on the Dream of Scipio (fourth century AD). Artemidorus had distinguished between oneiros and enhypnion, the first being a prophetic dream and the latter being a symptom of physical or emotional distemper: [End Page 185]

Oneiros differs from enhypnion in that the first indicates a future state of affairs, while the other indicates a present state of affairs. To put it more plainly, it is the nature of certain experiences to run their course in proximity to the mind and to subordinate themselves to its dictates, and so to cause manifestations that occur in sleep, i.e., enhypnion. For example, it is natural for a lover to seem to be with his beloved in a dream and for a frightened man to see what he fears, or for a hungry man to eat and a thirsty man to drink. . . . The name itself is significant, not insofar as all those who see it are asleep (since oneiros is also the product of sleepers), but insofar as the operation of the enhypnion is limited to the duration of one’s sleep; the minute the sleeping ends, it disappears. The oneiros, being an enhypnion (something in one’s sleep), is also active during that period, calling to the dreamer’s attention a prediction of future events; but after sleep, it is the nature of the oneiros to awaken and excite the soul by inducing active undertakings.25

In his analysis of Artemidorus’s Interpretation of Dreams, Michel Foucault characterized the enhypnion as a dream with “a simple diagnostic value” and “grounded in the current state of affairs (from present to present),” capable of indicating to the sleeping subject his or her own state and of “shaping” his or her own soul.26 Peri enhypnion was the title commonly given to treatises on dreams that approached dreaming from a physiological point of view, like Aristotle’s own Peri enhypnion. Artemidorus had also distinguished between two kinds of oneiroi: contemplative (theorematikoi) and allegorical (allegorikoi). Contemplative dreams were to be interpreted literally, while allegorical dreams required interpretation, as they were symbolic representations of something other than what they directly showed.27

Two centuries later, Macrobius had distinguished between five types of dreams: somnium, an enigmatic dream which requires interpretation; visio, a prophetic display of the future exactly as it would happen; oraculum, in which a parent, a venerable person, or even a god appears to give instructions about the future; insomnium, or nightmare; and visum, an apparition.28 Even though Cardano does not refer directly to Macrobius as he [End Page 186] does to Artemidorus—in fact, the total absence of Macrobius in Somniorum Synesiorum Libri IIII comes as a surprise—the Commentary on the Dream of Scipio, widely known in medieval Europe, continued to be highly influential throughout the Renaissance.29 Cardano was certainly familiar with it and, in fact, the same Latin words he uses to refer to different kinds of dreams—insomnia, somnia, visa, visiones—are deployed by Macrobius. What is more, the etymological connection of oraculum to voice and sound may suggest a direct influence on Cardano’s concept of idolum. It is also likely, however, that idolum was Cardano’s direct translation of Artemidorus’s theorematikos oneiros, although toward the end of the book he deliberately neglected the word’s link to the sense of sight. In any case, his choice of using the word insomnia only to refer to visa and not to idola is evidence of his desire to make a clear distinction between dreams originating from psychological and physiological causes and prophetic dreams caused by heavenly influences that take on corporeal qualities as they reach the human soul.30 Resulting from the joint action of the soul and heavenly forces, idola, for Cardano, are natural manifestations of intelligible realities: “Those dreams that come from a higher cause are set in motion by an influence that comes from the heavenly bodies. This influence is so organized that, in the soul, it arranges the images suitable to produce an effect in such an order that it produces an image [species] similar to that effect. It is as if somebody had many different little stones, of different colours and sizes, and he were such a talented artist that he would be able to depict, in a picture, the outline [ichnographia] of anything [whether men, animals or plants].”31

Idola are more powerful than visa and, unlike all other kinds of dream, cause the dreamer to feel awe (idolum ergo admirationem parit).32 Visa, however, are the most common kind of dreams, those dreams that happen during ordinary nights of sleep. They depend on the sense of sight and on the faculties of the imagination and memory and are produced by the gentle [End Page 187] motion of the animal spirits. In medieval and Renaissance medicine, the animal spirits, or “spiritus,” were understood as a vaporous and warm substance, flowing throughout the body by means of the nervous system. They played a crucial role in sense perception and in the exercise of the faculty of the imagination. In his Three Books on Life, the famous fifteenth-century Platonist philosopher and physician Marsilio Ficino says that “the spiritus is defined by doctors as a vapor of blood—pure, subtle, hot and clear. After being generated by the heat of the heart out of the most subtle blood, it flies to the brain; and there the soul uses it continually for the exercise of the interior as well as the exterior senses. This is why the blood subserves the spirit; the spirit, the senses; and finally, the senses, reason.”33 When we are deeply asleep, Cardano believed, the spirits gently flowing out from the heart transmit to the imagination the images that are formed in the mind.34

Dream-images arise from the combined action of the spirits and the imagination, in a process inspired by an imaginative élan similar to the tendency of the human eye to spot clouds with the shapes of animals in the sky.35 “In the organ of the imagination,” Cardano explains, “as in a calm sea, the spirits move gently, for they are made of an aerial and fiery substance, if not of an even better one, and from them souls represent images of things.”36 Moreover, he writes, “So all the kinds of dreams share this light motion of the spirits; and all share the same material. For the material of all of them is the memory of things heard and seen, and all dreams come into being from these.”37 Visa, ultimately, rely on the physiology of the imagination which conjures up images from the past. After all, “to remember” is to imagine things which are no longer there.

When strong external stimuli act on a vivid imagination and on calm spirits, the resulting dreams are numerous and clear. This is the case, for example, with people suffering with black bile. By contrast, those who have a weak imagination and receive feeble stimuli—especially when such stimuli are located in the moister part of the brain—have only a few effete and [End Page 188] vague dreams. Drunken people and children, he believes, belong to this latter category.38 Spirits and the imagination, therefore, play a fundamental role in rousing images from the past and presenting them to the soul, which reenacts them in the process of dreaming.

Memory, however, always brings sorrow to the dreamer, and even more so when in sleep it evokes pleasant sensations from one’s past. When we wake up, we suffer as we find out that those feelings of delight, peacefulness, or excitement were just dreams. One way or another, the past, recreated in sleep, always induces emotional responses to the experience of loss and interruption. Memory-dreams—like photographs—grieve the passing of time. Idola are of a completely different nature. They do not involve emotional states of mind that distress the soul with strong joy or sorrow.39 They always inspire a noble feeling of admiration for the greatness of the perceived object; they are pure in each of their parts, lucid and beautiful, even when they signify dreadful things.40 While visa are short, composed of segments that often fade into each other, and represent the same contents over and over again, idola are never repetitive and what they say is always new. A representative example of an idolum is the dream of the Greek poet Simonides, who, as tradition has it, found a dead body on the seashore and buried it. He had planned to sail to Asia Minor the next day, but that night the dead man appeared to him in a dream, warned him, and persuaded him not to leave. Simonides tried in vain to prevent his companions from departing and they all died in a shipwreck.41 Unlike ordinary dreams, the dead man summoned up the poet’s upcoming death from the store of forthcoming events and made the future speak to Simonides directly.

The future, Cardano believes, does not make itself known through prophetic visions or enrapturing coups d’oeil. It speaks to the soul in very brief and appropriate words (voces perbreves et appositas). Idola, then, are characterized by clear and effective voices, while in memory-dreams there are [End Page 189] no words, or these are confused or jumbled and part of long speeches (voces nullae aut perturbatae vel incompositae, aut cum longis sermonibus).42 This leads to a startling claim at the beginning of book 4: “The dreams that are called idola reveal the reality of things [res ipsa] and are based for the most part on speech and hearing, not on sight.”43

This passage, which comes only toward the end of the book, is crucial to the understanding of Cardano’s view of prophetic dreams. The vigorous claim for the identification of idola with auditory experiences suggests a sudden departure from the literary and philosophical tradition that had considered eidôla as visible species. Cardano’s reasons for such a claim—which represents, no doubt, the greatest aspect of novelty of his Somniorum Synesiorum Libri III—are anything but straightforward. The idea that idola are based for the most part on sounds not only defies the dominant view that dreams, including prophetic ones, are mainly visual experiences, but also, intriguingly enough, seems to contradict even Cardano’s own position when he describes idola, for example, as having different parts that are “distinct” (distinctae) from one another and “perfect” (perfectae), which most likely refers to the composition of images rather than sounds.44 The examples of idola Cardano provides, moreover, mostly involve visual contents. An idolum is the dream of Pharaoh in which seven fat cows represented seven forthcoming years of prosperity, as interpreted by Joseph in Genesis 41:17–37; an idolum is the story of a father who beat his seven children and then died, dreamt by Cardano himself in January 1534, shortly before he was informed that his father-in-law had passed away at the end of the previous month.45 Finally, an idolum is the one described by Augustine in The City of God, where, Cardano writes, “A certain Praestantius asked a philosopher to solve a doubt, which he refused to do. The following night, though awake, Praestantius saw the philosopher coming close to him, solving the doubt and leaving shortly after.”46

What is more, in combining idola with sounds, Cardano does not hesitate to disregard the etymological connection of eidôlon with the act of [End Page 190] seeing and to refer instead to Artemidorus’s view that oneiros acquires its meaning from the participle on, “what is” or “what is true,” and from the verb eirein, “to speak.”47 Therefore, while ta enhypnia (insomnia) are mostly visual experiences, hoi oneiroi (idola) are auditory perceptions that always speak the truth. The ambiguity and apparent contradiction with which Cardano mostly describes idolum as a visual dream but at one point firmly connects it to “speech and hearing” is due to his belief that idola “are rarely pure, without something of a visio mixed to them [raro pura sunt, quin aliquid habeant visionis admistum].”48 Idola, therefore, have a complex nature, halfway between visual imagery and perceptions of sounds, sensory experience, and prophecy—the shadowy dimension of dreams and states of ecstatic wakefulness. Only in their purest form and on extraordinary occasions do they come as unmixed auditory phenomena.


Of all kinds of dreams, idola, no doubt, embody the spirit of Cardano’s account of dreaming as a natural aspect of being human within a world in which divine intelligence is hidden behind the screen of material images and sensory experience. They are manifestations of intelligible reality that, however, very rarely come to the dreamer in their purest form, that is, without being blended with ordinary dreaming experiences resulting from physiological conditions or emotional states. Thus, all idola have something missing, corrupted, or obscure.49 Cardano explains: “Just as if you see on the same plant green and yellow plums, you would not believe that they are of different kinds, but of the same kind, since they have the same origin. This is far more evident if you see different fruits, partly green and partly yellow: who would ever doubt that visiones and idola have the same nature and derive from the same cause? This is a proof that visiones are very truthful when they are connected to an idolum.”50

The reason why Cardano describes idola for the most part as visual [End Page 191] experiences is that they are almost always interwoven with other kinds of dreaming material resulting in visa and visiones. Even a quick look at the thirty-one examples of idola listed in book 4 will reveal that words, sounds, spoken warnings, or prophecies do not appear to be a main feature. In fact, in most examples, they are not at all a feature.51 However, there are extraordinary cases in which idola come free from the confusing presence of visa and instead of picturing the future by combining together images of persons and places, they announce it through powerful and impressive words. The most famous idolum of all, one so pure as to be considered a miracle, is the dream of Saint Joseph in which an angel spoke directly to him with the command “Get up, take the child and flee to Egypt, as there are some people who want to take his life.”52

In their purest form, idola are direct insights into the true nature of things and into the future, hints of divine life. They are entirely “in accordance with nature [secundum naturam],”53 “show things as they are [rem ut se habet ostendunt],”54 fill the soul with a sense of marvel for the content and provenance of the words they speak, and reveal the instantaneity of the past, the present, and the future in the hic et nunc of the auditory perception. “Also, it is proven,” Cardano notes, “that the answers perceived in sleep with the ears are purer than images [visiones], because through the ears one does not receive the simulacra of material things.”55 The prophecies given by the priestesses in Delphi are to be understood in this way, as “answers enveloped in darkness, but always true, whether it is a divine spirit [daemon] who foresees [the future] or not.”56

Idola are heard in obscurity, when the eyes are shut or blinded, but the mind is more responsive and more able to have heightened perceptions. Things being so, although Cardano classifies idola among dreams, they have little to do with sleeping: “Images are seen during sleep, while things that are heard are more suited to wakefulness, because sounds also wake us up.”57 [End Page 192]

Very intriguingly, nevertheless, idola seem to have little to do with our waking life as well. When we are awake, the soul is too susceptible to natural appearances to be able to perceive higher realities. Waking is often illusory, while idola are oneiroi, that is, essentially truthful. Since idola belong neither to sleep nor to waking life, there must be another condition in which the human mind acquires the ability to hear prophetic words. Such a condition, Cardano says, is the state of ecstasy, which is intermediate between sleep and wakefulness, although much more similar to wakefulness than to sleep: “In states of ecstasy, the sense of sight is asleep, not so the sense of hearing, except (as I said) partly. In sleep sight is more deeply asleep than hearing, for if one avoids a strong light, one can sleep (as many people are in the habit of doing) with one’s eyes open, without waking up.”58

In fact, wakefulness, sleep, and ecstasy differ according to the degree of clarity of perceived sounds: “It must be said that those who fall into states of ecstasy can hear but cannot see everything. In this, ecstasy differs from sleep: during sleep, indeed, one cannot hear a clearly articulated voice, while a sound disturbs the sleeper, otherwise it would not wake him up. By contrast, during states of ecstasy one can discern the voice itself, but the sound is airy and coming from a distance. When one is awake, voices are fully perceived, together with their sense and meaning.”59

When we are awake, the external senses are active and perceptions of sounds are strong, whereas during ecstasies the external senses are at rest and the power of the intellect is intensified. For this reason, in ecstasies sounds lack the strength of sensible perception and are perceived as “airy.” But since the intellect reaches much higher than the external senses, sounds heard during ecstasy have a transcendent nature. The idea that the sense of sight is deactivated during experiences of heightened perception was not unusual. Ecstatic states were thought to imply a complete or semi-complete emancipation from visible species coming from the outside world. The deactivation of sight was therefore considered essential to the intellectual ascent of the soul: the eyes being sightless, the intellect was thought to [End Page 193] acquire the perceptive ability to grasp the presence of God. Biblical characters who were said to have seen God had been blinded or dazzled by the intense light and during the Middle Ages waking visions were placed higher than allegorical dreams in the hierarchy of oneiric experiences.60 Mystical discourses were imbued with the idea that manifestations of the divine were experienced in darkness, where the soul would lose the external world and itself to find God. For example, in Hildegard of Bingen’s Scivias, completed around 1152, visionary experiences are described in detail as complex visions and then presented as being explicated by a voice. In the Renaissance, Ficino claimed that Moses’s encounter with God on Mount Sinai happened in a “mystical obscurity” in which the soul became more receptive to divine light and regarded it as the most sublime form of ascent to the divine.61 Likewise, Giovanni Pico della Mirandola believed that the soul can enjoy the glory of God without the veil of an image being interposed (nullo imaginis intercedente velo).62

Outside the context of the soul’s mystical experiences, though, sight was almost unanimously perceived to be superior to the other senses and was said to provide the most distinct and universal form of knowledge.63 [End Page 194] Science depended upon the observation of the visible properties of nature and was strongly associated with vision. When compared to hearing, it was claimed to be more precise and reliable because of the immediacy of the visual act, while hearing always presupposes time before an emitted sound is perceived and during which it is perceived. In his Commentary on Plato’s Symposium, Ficino explained that that sight could work from afar and do in an instant what hearing does in time. For, he concluded, “we first see the lightning and then we hear the thunder.”64 Images were definite and self-sufficient, while sound was considered evanescent and unreliable.

In Cardano’s work, however, the deactivation of sight did not imply a mystical ascent of the soul to God. He based his arguments for the superiority of hearing on the fact that simplicity was ontologically superior to mixedness. A sound is absolutely simple (sonus simplicissima res sit),65 hence hearing is superior to all other senses that have objects of a compound nature, like tastes, odors, and colors, which derive from the mixing of different primary qualities. Hearing is “more subtle and divine than sight,” he says, and “for this reason many blind people are shrewd, unlike deaf people.”66 Moreover, the purity of sound allows a harmony of opinions, which is usually absent when other sensible objects are under consideration.67 Consequently, “Hearing is subtler than sight, either because (as I said) such a noble sense is the only one that occurs with movement or because the objects of sight, such as colours, on account of their intensity, impair one another due to their contiguity. Moreover, sight refers to many sensible objects, hearing only to one, which is very simple.”68

The subtlety of hearing is also proved by the fact that supernatural phenomena, such as the interventions of demons and dead people, are more likely to be perceived through the ears than through the eyes. Perception through sight needs the object to be present and distinct in all its different qualities, such as size, form, and color. Sight, moreover, perceives many aspects at a time, working through different flows of the spirits (or spiritus), which convey the physical qualities of each object to the eyes. This is why, Cardano says, the optic nerves have deep channels: they need several currents of spirits to perform their functions. Nowadays we would say that the [End Page 195] optic nerves need a lot of bandwidth, which would also explain why we struggle much more in trying to perceive things by looking intently at them than by exercising any one of the other four senses.69 Even though it requires a more intense physical effort, sight delights the soul much more than any other sense.70 Blindness, Cardano says, is similar to death, for it prevents human beings from perceiving delightful things, like the stars and meadows.71 A person who has lost the capacity to see suffers from being aware of the great delight (voluptas) and pleasures (commodi) of which he has been deprived. On the other hand, with respect to intellectual life, blindness (like sleep) is a condition favorable to the empowerment of the higher faculties of the soul. In a nutshell, the blind, for Cardano, are unhappier than the deaf, but much more discerning, for it is hearing, not sight, that serves the intellect: “As regards those actions in which the ability of acquiring knowledge is involved, blind people are usually far superior to those who can see. For this reason, I would not consider it absurd to believe what is usually affirmed: that Homer was blind. We are convinced about this also by the fact that many men who excelled in their studies, although they were not completely blind, nevertheless had weaker eyesight than most other people usually did.”72

Like Derrida’s photographs, for Cardano, visa and visiones were representations of absence, rearrangements of the departed into a new spatiotemporal setting offered to the eyes of the dreamer. The essence of a photograph, Derrida claimed, lies in loss, because it fails to capture the present moment and is left with only a trace of the movement of time. Likewise, memory-dreams, for Cardano, always carry with them the specter of the past, which upsets the soul of the dreamer with glooming memories or with a sense of grief for what is gone. Perceptions of sound, by contrast, have an immediacy which allows the soul to hold to the “here and now” of the moment in which the auditory perception is taking place. What is more, sounds are the only forms of perception that come to the soul when this becomes emancipated from the body and all external senses—apart from hearing—are deactivated, as in ecstasy. On these occasions not only do sounds, i.e., idola, release the soul from a mournful connection to the [End Page 196] past, but also they speak the future. In this way, they give the soul access to the divine reality that lies beyond time.

In his Cardano’s Cosmos: The Worlds and Works of a Renaissance Astrologer, Anthony Grafton writes, “Cardano had lived—so he believed as his life drew to a close—not only in a world of wonders, but in one of signifiers. And he was never certain whether his ability to read some of these derived from regular natural processes which he had learned to decode or from the direct intervention of the divine being that accompanied him.”73

Cardano’s fascination with dreams derives from his unquenchable thirst for both the wonders and the signifiers of nature. Like astrology, oneiromancy gives the human mind mastery in understanding the significance of natural wonders and their intimate bonds with the supernatural. Somniorum Synesiorum Libri IIII hinges upon Cardano’s belief that limiting intellectual inquiry to the ordinary course of natural phenomena prevents the mind from discovering the rerum varietas which characterizes nature. As a physician, Cardano was, no doubt, interested in the state of humoral and emotional balance behind the production of phenomena of sense perception in sleep. However, as a master of divinatory practices and a scholar of dream interpretation, he was concerned only with those dreams which point to higher dimensions and reveal the intimate connection between the human mind and that divine intelligence which had designed the world “down to the smallest details and strewn [it] with clues to what these meant—a world that hummed with hidden but vital messages, that the scholar spent his life deciphering.”74

The unruly motion of sensible representations, Cardano believed, agitates the mind and makes the mechanisms of perception obscure. When perception is not based on material images and is free from the limits imposed on the soul by space and time, the soul becomes better able to abstract itself from the intrusive distractions of the outside world and acquire heightened perceptions through sounds (idola). The most intriguing aspect of Cardano’s idolum was precisely its not being an idolum, namely, an image, but a non-visual representation of the invisible which revealed—through enrapturing words—what was concealed behind images: the hidden nature of things. [End Page 197]

Anna Corrias
University College London.

This article is inspired by the work of Eduardo Cadava and Guido Giglioni, to whom is dedicated.


1. Jacques Derrida, Athens, Still Remains: The Photographs of Jean-François Bonhomme, trans. Pascal-Anne Brault and Michael Naas (New York: Fordham University Press, 2010), 2–3.

2. On eidôla in ancient Greek culture, see Mercedes Aguirre, “Some Ghostly Appearances in Greece: Literary and Artistic Sources,” Gerión 27 (2009): 179–89; Ruth Bardel, “Eidôla in Epic, Tragedy and Vase-Painting,” in Word and Image in Ancient Greece, ed. N. Keith Rutter and Brian A. Sparkes (Edinburgh: Edinburgh University Press, 2000), 140–60.

3. See Norman Austin, Helen of Troy and her Shameless Phantom (Ithaca, NY: Cornell University Press, 2008); Hilda Doolittle, Helen in Egypt (New York: New Directions Books, 1974); Ingrid E. Holmberg, “Euripides’ Helen: Most Noble and Most Chaste,” The American Journal of Philology 116 (1995): 19–42; Michelle C. Jansen, “Exchange and the Eidolon,” Comparative Literature Studies 49 (2012): 327–47; Anne Newton Pippin, “Euripides’s Helen: A Comedy of Ideas,” Classical Philology 55 (1960): 151–63.

4. Epicurus, Letter to Herodotus, 47.9.

5. Lucretius, On the Nature of Things, 4.30, trans. Alicia E. Stallings (London: Penguin Books, 2007).

6. See the account of eidôla in Plato’s philosophy given by Francis M. Cornford in Plato, Plato’s Theory of Knowledge: The Theaetetus and the Sophist, trans. and comm. Cornford (London: Routledge, 2013; repr. of the 1935, 2000, and 2001 editions), 209–11.

7. Plato, The Sophist, 239D, trans. Harold North Fowler (Cambridge, MA: Harvard University Press, 1928), 346.

8. Plato, The Sophist, 240E, 353.

9. See Linda. M. Napolitano Valditara, Platone e le “ragioni” dell’immagine: Percorsi filo-sofici e deviazioni tra metafore e miti (Milan: Vita & Pensiero, 2007).

10. Peter T. Struck, The Birth of the Symbol: Ancient Readers at the Limits of Their Texts (Princeton, NJ: Princeton University Press, 2004), 54.

11. On the ochêma in ancient Platonism see E. R. Dodds, “Appendix II. The Astral Body in Neoplatonism,” in Proclus, The Elements of Theology, ed. Dodds, 2nd ed. (Oxford: Oxford University Press, 1963), 213–21; Robert Christian Kissling, “The ochêma-pneuma of the Neoplatonists and the De Insomniis of Synesius of Cyrene,” American Journal of Philology 43 (1922): 318–30; Andrew Smith, Porphyry’s Place in the Neoplatonic Tradition: A Study in Post-Plotinian Neoplatonism (The Hague: Nijhoff, 1974); Joseph Bidez, Vie de Porphyre (Ghent: Van Goethem, 1913), 89ff.; John F. Finamore, Iamblichus and the Theory of the Vehicle of the Soul (Chico, CA: Scholars Press, 1985); Maria Di Pasquale Barbanti, Ochêma-pneuma e phantasia nel Neoplatonismo: Aspetti psicologici e prospettive religiose (Catania: CUECM, 1998).

12. Synesius, On Dreams, 7.10, trans. Isaac Myer (Philadelphia: Isaac Myer, 1888), 10.

13. Synesius, 20.

14. Synesius, 20. See Homer, Odyssey, 7.48.

15. Synesius, 21.

16. See Jay Bregman, Synesius of Cyrene, Philosopher-Bishop (Berkeley: University of California Press, 1982), 150.

17. Porphyry, Sententiae ad intelligibilia ducentes, 29.

18. See Bregman, Synesius of Cyrene, 148.

19. On Somniorum Synesiorum Libri IIII, see Alice Browne, “Girolamo Cardano’s Somniorum Synesiorum Libri IIII,” Bibliothèque d’Humanism et Renaissance 40 (1979): 123–35; Guido Giglioni, “Synesian Dreams: Girolamo Cardano on Dreams as Means of Prophetic Communication,” Bruniana & Campanelliana 16 (2010/2): 575–84; Anthony Grafton, Cardano’s Cosmos: The Worlds and Works of a Renaissance Astrologer (Cambridge, MA: Harvard University Press, 1999), 165–69; Nancy Siraisi, The Clock and the Mirror: Girolamo Cardano and Renaissance Medicine (Princeton, NJ: Princeton University Press, 1997), 174–94; Jacques Le Brun, “Jérôme Cardan et l’interpretation des songes,” in Girolamo Cardano: Philosoph, Naturforscher, Arzt, ed. Eckhard Kessler (Wiesbaden: Harrassowitz, 1994), 185–206; Markus Fierz, Girolamo Cardano 1501–1576: Physician, Natural Philosopher, Mathematician, Astrologer, and Interpreter of Dreams, trans. Helga Niman (Boston: Birkha¨user, 1983), 125–56.

20. See Ian Maclean, “A Chronology of the Composition of Cardano’s Works,” in Girolamo Cardano, De libris propriis: The editions of 1544, 1550, 1557, 1562, with supplementary material, ed. Maclean (Milan: Franco Angeli, 2004), 43–111; Cardano, Somniorum Synesiorum Libri IIII, ed. and trans. Jean-Yves Boriaud, 2 vols. (Florence: Olschki, 2008), 2:1, v–x (hereafter cited as SS).

21. SS, 2:1, 26: “caput polypi, caules, coepe, fabae, et quaecumque caput petunt, et praecipue atram bilem generantia.”

22. See Giglioni, “Synesian Dreams,” 576.

23. SS, 2:1, 64: “Somnia quidem quae abdita nos docent, alia quidem simpliciter ea ostendunt, vocanturque idola; alia autem artificiosa coniectura opus habent, vocanturque insomnia, seu visa.”

24. On the influence of Aristotle on late-medieval dream theory, see Steven F. Kruger, Dreaming in the Middle Ages (Cambridge: Cambridge University Press, 1992), 83–89.

25. Artemidorus, The Interpretation of Dreams, trans. Robert J. White (Park Ridge, NJ: Noyes, 1975), 15.

26. Michel Foucault, The Care of the Self, vol. 3, The History of Sexuality, trans. Robert Hurley (New York: Vintage Books, 1988–90), 10–11.

27. Artemidorus, The Interpretation of Dreams, 15.

28. Macrobius, Commentary on the Dream of Scipio, trans. William Harris Stahl (New York: Columbia University Press, 1952), 3.2.

29. See Stéphanie Lecompte, La chaîne d’or des poètes: Présence de Macrobe dans l’Europe humaniste (Geneva: Librairie Droz S.A., 2009); Christopher Ligota, “L’influence de Macrobe pendant la Renaissance,” in Le Soleil à la Renaissance: Sciences et mythes (Bruxelles: Presses universitaires de Bruxelles / Paris: Presses universitaires de France, 1965), 463–82.

30. SS, 2:1, 34–36.

31. SS, 2:1, 34: “Quae ergo a superiore causa contingunt, moventur ab influxu qui a corporibus contingit coelestibus; atque hic adeo ordinatus est ut species in anima convenientes effectui procreando eo ordine moveat, ut similem speciem effectui illi conficiat, velut si quis lapillos plurimos habeat diversorum colorum ac magnitudinis, sitque adeo peritus artifex, ut quarumcunque rerum imaginem seu hominum seu animalium, aut plantarum in tabula ichnographiam repraesentare norit.”

32. SS, 2:2, 482.

33. Marsilio Ficino, Three Books on Life, ed. and trans. Carol V. Kaske and John R. Clark (Binghamton, NY: MRTS, 1989), 1.2, 111. On the spirits in Renaissance medicine see especially Daniel P. Walker, “The Astral Body in Renaissance Medicine,” Journal of the Warburg and Courtauld Institute 21 (1958): 119–33.

34. Cardano, De immortalitate animorum, ed. José Manuel García Valverde (Milan: Franco Angeli, 2006), 323–24 (hereafter cited as DI).

35. DI, 324.

36. DI: “In instrumento igitur imaginationis, ut in tranquillitate maris spiritus leviter moventur, sunt enim ex aëria, igneaque substantia, vel etiam siqua melior est, unde animae repraesentant rerum imagines.”

37. SS, 2:1, 28: “Omnia igitur genera insomniorum in hoc uno levi motu spirituum conveniunt; conveniunt et omnia in materia; est enim singulorum materia, recordatio visorum et auditorum; namque nulla fiunt insomnia, nisi de illis.”

38. SS, 1:1, 323.

39. SS, 2:2: “Idolum ergo admirationem parit, ἀναμνηστικóν autem terrorem atque dolorem, quia hi affectus, aut si de re laeta sit somnium, contrarii cum memoria eius rei necessario coniuncti sunt.”

40. SS, 2:2, 482: “Praeterea in idolo partes sunt distinctae admodum, et perfectae, et est prolixum sine revolutione; anamnesticum autem est cum motu concitato, cum partibus parum bene distinctis, et breve, vel cum reditu ad eadem.”

41. SS, 2:2, 562–64: “Simonides poëta cum ignotum quendam proiectum mortuum vidisset eumque humavisset, haberetque in animo navem conscendere, moneri visus est ne id fac-eret, ab eo quem sepultura affecerat, si navigavisset, eum naufragio esse periturum; itaque Simonidem redisse, perisse caeteros qui tum navigassent.” See Cicero, On Divination, 1.56.

42. SS, 2:2.18, 482.

43. SS, 2:2, 550: “Duorum cum sint generum somnia, alia quidem quae rem ipsam declar-ant, idola vocata, quorum maxima pars oratione et auditu, non visu constat.”

44. SS, 2:2.18, 482.

45. See SS, 2:2, 479 and 1:1, 91.

46. SS, 2:4, 569: “Praestantius, vir quidam, a Philosopho petierat dubitationem quandam solvi; quod ille pernegavit. Nocte sequente, tametsi vigilaret Praestantius, videt sibi Philosophum assistere, ac dubitationem solvere, moxque abire.” See Augustine, The City of God, 18.18. However, it was not Praestantius who reported the dream, but somebody else.

47. SS, 2:1, 42. See Artemidorus, The Interpretation of Dreams, 15: “This is how it originally got its name, if it does not come from ‘telling’ (eirein) what is real (to on).”

48. SS, 2:2, 480.

49. SS, 2:2, 478: “In omnibus [idolis] aliquid desit; aut perversum est, aut obscurum.”

50. SS, 2:2, 480: “Velut ergo si videas in planta eadem pruna viridia, alia colossena, non diversarum specierum illa existimabis, sed unius, quod eandem habeant originem; longe vero evidentius, si plures spectes fructus, partim viridies, partim colossenos; quis dubitat visiones atque idola non unius esse naturae, et ab eadem causa proficisci? Visionum itaque verissimarum argumentum est, cum idolo iunctae sunt.”

51. SS, 2:4, 558–71.

52. SS, 2:2, 481: “Surge, et tolle puerum, et vade in Aegyptum; sunt enim qui animam pueri quaerant.” See Matthew 2:13.

53. SS, 2:2, 482.

54. SS, 2:2, 477.

55. SS, 2:2, 558: “Liquet autem quod responsa auribus per somnum percepta puriora sunt visis, quod auris non excipiat simulachra rerum materialium.”

56. SS, 2:4, 558: “Responsa caligine involuta, vera tamen semper, seu daemon sit qui praevideat, seu non.”

57. Cardano, Contradicentium medicorum libri duo, in Opera Omnia, 10 vols. (Lyon: Ioannes Antonius Huguetan and Marius Antonius Ravaud, 1663; repr. Stuttgart-Bad Cannstatt: Friedrich Frommann, 1966), 10:6, 486: “visa in somnio, audita vero vigiliae magis conveniunt, quod sonus etiam expergisci nos cogat.”

58. SS, 2:2, 432: “In ecstasi ipsa sopitur visus, non auditus, nisi (ut dixi) ex parte. Plenius etiam in somno visus quam auditus; nam delato lumine magno, tametsi apertis (ut multi facere solent) dormiat oculis, non expergiscitur.”

59. SS, 2:2, 431–32: “Dicendum est ergo eos qui ecstasim patiuntur omnia audire, non autem videre, atque in hoc a somno differt; nam in somno discreta vox non intelligitur, sonus autem dormientem movet, aliter non excitaretur; in ecstasi autem etiam vox ipsa intelligitur sed quasi sonus aurae et procul veniens; in vigilia autem tota vox percipitur, cum sensu atque significato vocis.”

60. See Kruger, Dreaming in the Middle Ages, 120.

61. See Michael J. B. Allen, “Dove le ombre non hanno ombre: Marsilio Ficino e l’ascesa al Sinai,” Rinascimento 49 (2009): 15–26.

62. Giovanni Pico della Mirandola, “Oratio,” in Opera omnia (Venice: H. Scotus, 1557), 57.

63. Another Renaissance philosopher to rank hearing over sight was Charles de Bovelles. See T. Frangenberg, “Auditus visu prestantior: Comparison of Hearing and Vision in Charles de Bovelles’s Liber de sensibus,” in The Second Sense: Studies in Hearing and Musical Judgement from Antiquity to the Seventeenth Century, ed. Charles Burnett, Michael Fend, and Penelope Gouk (London: Warburg Institute, 1991), 71–89. On the hierarchy of the senses in the Renaissance, see Alastair C. Crombie, “The Study of the Senses in Renaissance Science,” in Proceedings of the Tenth International Congress of the History of Science, ed. Henry Guerlac, 2 vols. (Paris: Hermann, 1964), 2:1, 93–117; Giglioni, “Phantasms of Reason and Shadows of Matter: Averroes’s Notion of the Imagination and Its Renaissance Interpreters,” in Renaissance Averroism and Its After-math: Arabic Philosophy in Early Modern Europe, ed. Anna Akasoy and Giglioni (Dordrecht: Springer 2013), 173–93; and Giglioni, “Sense,” in Renaissance Keywords, ed. Ita Mac Carthy (Oxford: Legenda, 2013), 11–26; Ernst H. Gombrich, “Botticelli’s Mythologies: A Study in the Neoplatonic Symbolism of His Circle,” Journal of the Warburg and Courtauld Institutes 8 (1945): 7–60; Frank Kermode, “The Banquet of Sense,” Bulletin of the John Rylands Library 44 (1961): 68–99. On the sense of sight in early modern Europe, see Stuart Clarke, Vanities of the Eye: Vision in Early Modern European Culture (Oxford: Oxford University Press, 2007); David C. Lindberg and Nicholas H. Steneck, “The Sense of Vision and the Origins of Modern Science,” in Science, Medicine and Society in the Renaissance: Essays to Honor Walter Pagel, ed. Allen G. Debus, 2 vols. (New York: Science History Publications, 1972), 2:1, 29–45. On the sense of hearing, see Hearing History: A Reader, ed. Mark Michael Smith (Athens and London: University of Georgia Press, 2004).

64. See Ficino, El libro dell’amore, ed. Sandra Niccoli (Florence: Olschki, 1987), 78: “Prima si vede el baleno che s’oda el tuono.”

65. Cardano, De subtilitate, in Opera omnia, 10:3, 572.

66. SS, 2:2.8, 432: “Auditus ergo tenuior est, et magis divinus, quam visus. Ob id etiam caeci multi, prudentes, non ita surdi.”

67. SS, 432.

68. SS, 573: “Subtilior igitur auditus visu, vel quia (ut dixi) illius sensus solus fit cum motu, aut quia visus obiecta, scilicet colores, ob vehementiam contiguitate vitiant se mutuo, aut quia visus sit multorum, auditus autem simplicissimi atque unici obiecti.”

69. SS, 652.

70. DI, 324.

71. Cardano, De utilitate, in Opera omnia, 10:2, 71.

72. Cardano, De utilitate, 72: “quae ad cognitionem pertinent, caeci videntibus longe praestare solent. Quo fit, ut, absurdum non existimem credere, quod affirmari consuevit, Homerum caecum fuisse. Etenim id et hoc suadet, quod multi in disciplinis egregii viri, tametsi non penitus caeci fuerint, visu tamen valuerint minus quam communiter alii.”

73. Grafton, Cardano’s Cosmos, 169.

74. Grafton, “Introduction,” in Cardano, The Book of My Life, trans. Jean Stoner (New York: New York Review of Books, 2002), xiii.

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