NB: I just discovered this image so this post will be brief and very tentative. I hope to follow it up with more extensive research soon and will post a more expansive discussion of this image at a later time.

Last week, while I was working on revising a post on vision in Hobbes’ Leviathan (1651) and his earlier “Short Tract on First Principles,” I noticed a shocking detail in the striking image of ocular anatomy in another Hobbes manuscript, “A Minute or First Draft on Optiques,” that I wanted to share immediately (Harley MS 3360 at the British Library).1 When I discovered “A Minute or First Draft of the Optiques” several months ago while fleshing out some preliminary research on Hobbes’ optics, I found the following image of the way in which the eye connected to the brain rather impressive, but simply saved a copy to return to when I was ready to work more extensively on Hobbes and did not, at that time, give it the attention it deserves.

The brain and the eye in Thomas Hobbes’ “A Minute or First Draft of the Optiques” (BL Harley MS 3360), f. 6r.

The fascinating illustration not only shows the ocular anatomy, but also shows the way in which the optic nerves enter and join within the brain. What I did not notice before, however, was that the image contained a secret that peered through a correction that its author and/ or illustrator had attempted to conceal. I discovered that this image contained a double vision within its representation of the eye and ocular anatomy.

In my earlier digital essay on ocular anatomy, I defined three types of early modern eyes common from the mid-sixteenth century to the early seventeenth century. The first, which I call the “Galenic eye,” which placed the “crystalline humor” or lens at the very center of the eye, and its influence continued at least until the publication of Andreas Vesalius’ De Humani Corporis Fabrica in 1543. The second type of early modern eye, which I call the “mediate early modern eye,” is, by far, the most common representation of ocular anatomy from roughly the 1550s to at least the 1620s, and places the crystalline humor somewhere between the very center of the eye and the front of the eye. The third type of eye, which I call the “modern eye,” roughly corresponds to the ocular anatomy that we know of today, which places the lens towards the front of the eye.2

When I first saw the illustration of the eye in Hobbes’ “A Minute,” I merely saw it as a mid-seventeenth-century illustration of the “modern eye” which, although the orb of the eye was perfectly spherical, looks very similar to the optical anatomy accepted today. What I did not realize then was that this illustration was far more remarkable than it initially appeared. Here is a close-up of the same image:

Detail of the ocular anatomy in Thomas Hobbes’ “A Minute or First Draft of the Optiques” (BL Harley MS 3360), f. 6r.

While I have only seen the wonderful digitization of BL Harley MS 3360 available on the British Library’s online manuscript collection and not in person, what we have here is a pasted-in correction to the ocular anatomy that conceals a second original illustration.3 But, like an afterimage one sees after staring at the sun, the original illustration persists and remains visible. This original illustration has slowly bled through the pasted-in correction, revealing a very different ocular anatomy lying just beneath the modern eye.

Beneath this illustration of the “modern eye,” one can clearly discern in the bleed-through, that a “Galenic eye” lies beneath. This Galenic eye, with its central placement of the crystalline humor or lens, persisted at least as far as Andreas Vesalius. For comparison, see Vesalius’ eye:

The eye as Vesalius represents it in his De Fabrica. This image from a Venetian 1568 edition, page 495.

It is clear from the text of the manuscript that Hobbes was familiar with Kepler’s discovery of the retinal image and the retinal inversion, but, in the illustration at least, the original manuscript illustration did not even follow the model of the “mediate early modern eye” that was the standard representation from around the 1550s to the 1620s. Instead, the illustrator represented the older model which placed the crystalline humor directly in the center of the eye’s orb.4 In the descriptive key to the image of the way the eye connects to the brain through the optic nerve, Hobbes’ description separates the Christalline humor (I) from the center of the eye (K). He notes that

I is the Christalline humor, which is a cleere glacie & clammie humor of the colour of Christall, enclosed with a thin coate, and hung to the sides of the Eye round about with a coate like a band or collar full of black fibres which they call processus ciliares, expressed by AG & BH.
K is the center of the Eye, and the space within the inner circle GCH, is filled with a liquor, which they call humor vitreus, The colour whereof is not so cleere as of the ether two liquors, The consistence between that of the Christalline humor, and that of the watry humor. (A Minute Fol. 6v).

Hobbes clearly describes two different reference points with the vitreous humor filling the center of the eye, and a lens suspended by “processus ciliares” towards its front, but the illustrator presented a very different picture in the original illustration. But, at the same time, the manuscript reveals a double vision of ocular anatomy that reveals the lasting power of that older model–even if only shown through an illustrator’s error.

As we can see in what has bled through the pasted-in correction, the original illustration placed I and K in the space occupied by the crystalline humor or lens. This follows a model of ocular anatomy that can be found in Vesalius, but that model had been discounted nearly a century before.5 What we have here is a double vision of the eye. One, the modern view of ocular anatomy, and another, a model that had been outdated for nearly a century but which had persisted for over a millennium, coexisting within the same image. Discovering this image reminds me to be cautious in the way I present and address broad sweeping historical change. Even though the “Galenic eye” had been dismissed nearly a century before and even in a text that describes the mechanics of a modern eye, it bleeds through and affects the image of the eye and the understanding of vision for much longer. While it is clear that Hobbes understood and grappled with the new ocular anatomy, it is not clear that his illustrator did initially.6 This newer model, for whatever radical historical changes it may have contributed to, still, for some time and to some extent depended upon the theoretical systems developed centuries before. Rather than seeing a Foucaultian radical shift in episteme, we see the refusal of that older model to disappear completely or quickly. The illustrator, whose skill in anatomical illustration can be seen in the way he represents the brain and who must have been familiar with human anatomy to some degree, errs by falling back to the “Galenic eye,” even though it had been dismissed nearly a century before in elite discourse.

It is even clearer later in the manuscript that Hobbes and the illustrator follow the conventions of the “modern eye.” In the following image, which depicts the retinal inversion, clearly shows an eye that is closer to the eye of modern optical anatomy.

The modern eye in Thomas Hobbes’ “A Minute or First Draft of the Optiques” (BL Harley MS 3360), f. 51r.

In the text itself, Hobbes manifests a familiarity with Kepler’s optical discovery, discussing the retinal inversion directly when he says,

Insomuch as every point of the object designes it selfe orderly there, and makes an image of it selfe inverted; And though no man can bee so well assured of the quantity of refraction which the severall humors make, nor of the figure of the foremost coate, nor of the hinmost coate, of which one is called cornea, the other retina, nor of the figure of the Christalline humor so as to demonstrate that all beames from one point without, must of necessity come to one point within, yet experience maketh manifest that the Image in that part, to one yet shall have an eye in his hand, and looke on the hinderpart of it (having first taken away that part of both the utter coates, that the Retina may bee seene) shall bee seene as distinctly as the object itself. And because this cannot bee, unless all the beames that fall on … one point of it, come also, from one point of the object without, It may with ground enough bee concluded, that the eye, if it bee perfect, hath the figure & substance required to produce that effect. But here againe I must admonish the Reader, not to mistake this image for that which wee have in our mind upon sight of the object with our owne eyes. For no man can see the image described in the bottome of his owne eye, because hee cannot see the Eye in his owne head, or if hee could, hee should see a double image, unless hee bee single-eyed, the object working on both eyes equally; besides the image wee see in the bottome of the eye is inverted, butt when wee behold the object, the image wee have of it is nott inverted.

In this passage and through most of Hobbes’ “A Minute,” Hobbes and his illustrator recognize the retinal inversion and depicts an eye that functions through a lens as an agent for focusing light on the retinal screen rather than as ascribing the power of sight to the centralized power of the crystalline humor. His illustrator, in this later image and in the correction to the first, depicts eyes that are more in line with the more accurate representations of ocular anatomy found following Christoph Scheiner’s first anatomically correct eye in his Oculus hoc est: Fundamentum opticum of 1619.

Despite this double vision in the first image of ocular anatomy in “A Minute,” Hobbes does reflect a radical and revolutionary change in the theory of optics occurring in the seventeenth century.7 Not only does he register Kepler’s discovery of the retinal image and its inversion, but also declares that the experience of visual phenomena has more to do with the fantasy or Fancy than with the image within the physical eye itself. In his Epistle to the Marquise of Newcastle, Hobbes writes,

That which I have written of it, is grounded especially upon that which about 16 years since I affirmed to your Lordship at We[s]b[o]ck, that Light is a Fancy in the minde, caused by motion in the braine, which motion againe is caused by the motion of the parts of such bodies, as wee call lucid, such as are the Sune and the Fixed stars, and such as here on earth if fire. (Fol. 3r)

Here, Hobbes declares light as well as the experience of perception to “motion[s] in the braine,” which is one he reiterates at the beginning of his Leviathan where he states that “Sense in all cases, is nothing els but original fancy” (Hobbes 4). Even if those motions have their origins in the “motion” of external things upon the sense, the motions in the body do not directly correspond to phenomenal reality. Instead, phenomenal reality is constructed by the Fancy from the motions of the brain and body. This stance, that all perception occurs in the fantasy is supported and builds upon, in part, Kepler’s radical revolution in optical anatomy. As I discussed in my previous digital essay, though, Kepler refused to speculate beyond the opaque wall of the retinal screen, leaving it to others to determine how this image rights itself and finds its way into the brain. Kepler left it to successors like Descartes, Hobbes, Berkeley and others to argue and speculate about that transmission.8 Here and in Leviathan, Hobbes offers that the image in the eye matters very little since what we experience as “sight” is constructed within the fantasy.

The splitting of the image within the eye and the motions of the brain from phenomenal experience and reality takes part in a broader shift towards the mechanization of nature and the body. Once applied to the eye, to optics, and to vision, this mechanization created a greater divide between sensation and perception. Sensation was what occurred in the materiality of the body while perception was what occurred in a more immaterial mind. For Hobbes, of course, the opposite was true. In contrast to Descartes who emphasized an immaterial mind, Hobbes declares the mind, spirit, and soul as profoundly material. At the same time, however, he, like Descartes, voided the sensory system of its dependence on mimesis. Perception itself becomes the phenomena experienced by the mind in a fantasy that no longer has theoretical links to the external senses where quasi-material or paramaterial objects remain in a chain of mimesis from the objects of the external world, through the external senses, and into the spirits of the brain itself. In seventeenth century theories like those of Descartes and Hobbes, sensation, as well as its associated movements in the substance of the brain, shifts towards being represented along the lines of a mechanized pressure model that further separates sensation and the body from perception.9 At a fundamental level, such theories of the sensorium abandon the need for similitude altogether, interposing between the image projected upon the rear surface of the eye and its translation into perceived phenomena within the fantasy “motions” of the body’s substance that preclude any semblance of similitude and mimesis.10

Though my own sense of historical changes has never been one that pushed towards a totalizing master narrative as I try to avoid the pitfalls of Foucaultian episteme shifts or Kuhnian revolutions that overemphasize clear and radical historical breaks with the past, this image reminds me of the competing and often contradictory understandings of vision, the senses, the mind, and the self that complicate even the most tentative of claims about broad, radical, and quick historical and cultural changes. Even as this pressure model which further separated sensation from perception developed, however, the older model continued exerting its influence. No matter what types of broad historical shifts I hope and plan to map out concerning the restructuring, mechanization, and dematerializing of the human mind that I see as developing through the seventeenth century towards a modern liberal self by radically restructuring the early modern sensorium, the image in BL Harley MS 3360 reminds me that even in texts where newer models are offered, much older models may lie just beneath the surface, waiting to bleed through to obscure and blur any lines that might clearly determine a clean separation between the early modern and the modern.

Works Cited

Hobbes, Thomas. “A minute or first Draught of the Optique.” 1646. MS. British Library Harley MS 3360. (Digitization available here).

Hobbes, Thomas. The Leviathan. Prometheus Books, 1988.

Vesalius, Andreas. De Humani Corporis Fabrica. Venice: Apud Franciscum Franciscium & Joannem Criegher, 1568.

1. I will discuss this in my later post, but it should be noted here that there is a lot of debate as to whether or not Hobbes actually wrote the “Short Tract.”  (back)
2. See the first part of my earlier digital essay for a more substantial description of these three types of eyes, and the second part for a discussion of ocular anatomy and its representation as a microcosm.  (back)
3. This is clearly NOT a flap anatomy since the image that bleeds through represents an entirely different type of ocular anatomy  (back)
4. See my earlier post on info about how even the illustrations of optical anatomy in Kepler follow the conventions of the “mediate early modern eye” despite his recognition of the retinal image and its inversion.  (back)
5. Again, see part one of my earlier digital essay to learn more about how Vesalius’ optical anatomy was soon corrected by his successors.  (back)
6. Thus far, I have yet to find anything out about Harley 3360’s illustrator or find anything written specifically about this illustration, I will post an update when I do.  (back)
7. I am not suggesting Hobbes personally is creating a radical and revolutionary change, but rather that he takes part in a larger historical and cultural shift.  (back)
8. See my forthcoming essay on Hobbes and vision, and another on later developments in the thought of George Berkeley. I will add a links here when they are available.  (back)
9. For a brief explanation of what I mean by my own theoretical term “paramaterial,” please see this post.  (back)
10. I do not wish to suggest that this development was entirely new to post-Keplerian theories of the senses. While I have yet to post anything on the subject, the debates between the Stoics and the Skeptics depended upon the skeptics challenging the stoic notion that there was any way to determine between cataleptic and acataleptic perceptual objects. For Stoics, cataleptic phantasms were those caused by an object immediately before the external senses while acataleptic phantasms were those that were not caused by objects immediately before the external senses. For skeptics like Sextus Empiricus, there was no way to determine the cataleptic from acataleptic phantasms. See also my earlier post on Joseph Mede and his late sixteenth century crisis of sense which describes how the English Mede suffered a skeptical crisis in which he began to believe all of his perceptions were “mere phantasms.” While I will post more on this later, I will say here that these earlier questions about the relationship of external objects, the external senses, and the internal senses, still often depended upon a process and a sensorium that represented mental objects as objects rather than as “motions” in a brain that generate phenomenal experience within the mind—even if one could not determine the difference between cataleptic and acataleptic phantasms. This point requires more development, and, quite frankly, more research before I will state it entirely without reservation or hesitation.  (back)

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