The connections between Hooke, who presented several models of the camera obscura to the Royal Society, and Locke, who may have witnessed one or more of them there, may be strengthened, for they shared a mentor.21 This was Thomas Willis. Willis was a founding member of the Royal Society, but even before his days in London, he was part of the critical Christ Church group of scholars and natural philosophers that at different times included Hooke and Locke. Willis knew the slippery wetware of the brain better than anyone; he had pioneered the difficult surgical techniques making it possible, for the first time, to lay aside the lobes of the brain and penetrate to its delicate, ringlike vascular core. But despite the mess of fat and nerves with which he was left, he clung still to a chamber theory of mentation.22 Embedded in the brain, he surmised, is a “callous body” like a “white Wall.” In his Discourses Concerning the Souls of Brutes, Willis puts the matter this way: “Sent or intromitted by the Passages of the Nerves,” Willis writes, are the “Images or Pictures of all sensible things,” which are made to fall on this callous body.23 For each philosopher, it is as though the optic nerves from retina to ventral cortex carried perfect images, fiber-optic-like, and cast them upon a cartilaginous membrane. This specially textured reception surface, receiving impressions from without, produces “Perception[s],” that is, “Imagination[s] of the thing felt.” Willis, in his own poetic turn of phrase, calls this interior space the “Chamber of the Soul, glased with dioptric Looking-Glasses.”24 With allowances for Willis’s tradecraft, the brain surgeon has here anticipated the poetic image that would turn up in Akenside’s Pleasures of Imagination (Exhibit 3); Akenside surmises a “wide palace” of the brain, where images are staged and rearranged. And, through the mediation of more discrete metaphors—or are they more material gadgets?—Willis’s thoughts would descend directly to a series of similar spaces: Locke’s “dark room,” for instance, or what would become Hooke’s strikingly realized “Repository” of the mind (see Exhibit 11).
Were the drawing of Hooke’s camera obscura more rigorously exact, then, were it to have bisected the man just as neatly as it bisects the beak-like gadget in which he stands, we might have seen a second camera obscura, impossibly miniaturized, at work behind the large eye of the viewer.25 The first is made of ground glass, deal board, and oiled paper; the second is made of a strangely glass-like eye, curved bone, and sensitive membranes. In the first case, the camera obscura is an optical model; in the second, it is a model for mental work. Reproduced on the other side of the eye, invisibly, the camera obscura becomes a figure for judgment or awareness; indeed it becomes a figure that splits judgment from the objects it contemplates, producing consciousness as a tiny eye presiding over images from which it is half-screened. Like Descartes26 and Willis before them, Hooke and Locke differently offer versions of what has more recently been called the “homunculus fallacy”; it is as though a little person were sitting in front of a screen inside the head, watching a picture show on display. Just as the eye offers, in Hooke’s words, a “microcosm, or a little World” of the field of view that confronts it, so, too, this microcosm is put on display for the delectation of the understanding, the “Eye of the Soul” within.27 The homunculus thesis seeks to solve the problems introduced by a dualist epistemology, especially the critical problem of how sensory perceptions might cross the gap from matter to ineffable mind (and how, in turn, desire may be put into action); it solves these problems by shifting them up one level, to a mystical relationship between the mind and its ideas. The difficult conception of how ideas are received by the eye is shifted into the difficult question of how ideas are received by an internal eye. The critical question is not solved, however (see Locke’s remarks in Exhibit 19); it is merely kicked down the road, deferred perhaps until more precise instruments are available to unpack the mind’s strange commerce.
The homunculus thesis is typically understood as a fallacy. But we might look at the problem slightly differently; rather than looking at Locke or Hooke’s claims as profound dualisms, it makes sense to think about the networks that produce them, the patterns of modeling that express more profound entanglements. The mind finds itself in its environment through a heuristic twist. Experience models a mind through a readily available technical object, one that, as the engraving of Hooke’s gadget makes clear, swallows up and enwraps even the work of the hand. The value of models is not their exhaustive explanatory power; their value lies precisely in the thinking they make possible, an excess potential arising out of an initial metaphorical conjunction.28 The analogical hunch takes on a life of its own, giving way to a whole host of possibilities and realizations; this is precisely why models are good to think with.29 It is not that the eye of the understanding merely contemplates images; the work of the hand to design, to cut the world back to recognizable objects, distinctions, and lines is shifted into the process of witnessing. In this sense, the homunculus fallacy is not a fallacy at all; it is the natural extension of a mind being crafted in its environment. It is the proof that thinking is an ecological product—even when that product slashes an ecology into subject/object, viewer/view, mind/matter, but also understanding/memory, conscious mind/ materials of thinking.
Gadgets like the camera obscura, as metaphors and analogies, helped shape and make sense of the texture of experience. Locke remained skeptical, however, of the extent to which the materiality of the metaphor could be extended. When one thinks of the cathedral church at Worcester, Locke elsewhere remarks, no actual cathedral church pops into one’s head, nor any material similitude; when one thinks of a dark room, no actual dark room carves its way into the stuff of the brain. “When our ideas are said to be in our memories,” Locke remarks, “indeed they are actually nowhere.”30 But, precisely because it organizes a way of speaking, of what can be “said to be in our memories,” Hooke’s design or Willis’s “chamber” with its dioptric glasses offers a neurophysiology of epistemic dualism: “in” versus “out.” It offers a vocabulary, a way of speaking. How else would the mind speak of itself, other than through images that it had experienced? How else to speak about what is “in” the mind or “in” the senses, other than through a figure that was incorporated there? And so Locke can comfortably speak of contemplation as “bring[ing] in sight,” or ideas as “objects … imprinted” in memory, despite his suspicion that there are no materially isomorphic changes in the brain.31 In this sense at least, Locke is like Willis, characteristic of the mainstream epistemology of his moment. Like Willis, Locke adapts a physical space as the basis for reimagining the mind as an entity within and depending upon the “crankling … superfices” of the brain—with (in Willis’s words) its many “Cells” or “Store-houses.”32 Locke’s contribution is to gain control of the metaphor, insisting that it must be learned in the same way as anything else; it is acquired through the senses—by “experience,” which stocks the mind with its vast store—though no actual space seems to be present there.
This is how the camera obscura reigns as a metaphor, once for the eye, and again for the understanding. It is a metaphor for metaphor, metaphor’s model. But just as metaphor was important to poets, authors, and artists for the way it enabled a reverse flow, returning ideas to their haptic ground, so, too, Hooke’s camera obscura was clearly less intended to model a mental process than to enable a certain kind of practical activity. It was a device designed to allow the capturing of ideas in images, of, in other words, designs. This is to say that it was built less as a model of the mind (this in some ways was merely an accidental effect of the object), than it