We have always encountered the paradox between the imperfect human eye and the epistemic attempt to see perfectly, never ceasing to question the relationship between what we see and what is seen. In The Curious Eye, Erin Webster traces this paradox back to seventeenth-century England, where a group of natural philosophers, inspired by the compelling current of mechanical philosophy, compared naked eyes to and equipped them with optical lenses in order to overcome ocular flaws and reach inerrant observational objectivity. By studying scientific and figurative literature of the era, Webster questions the mechanistic claim that optics saves human vision from being distorted by misrepresentative analogy and subjective imagination. She argues that optics did not abolish the agency of metaphors and similes or the sensory affects they evoked in seventeenth-century English intellectuals’ observations. Instead, metaphorical implications served as “literary lenses” (7), cohering with human eyes and optical instruments to channel the way these observers thought of the universe and their positions in it.

Webster opens The Curious Eye by investigating the changing notion of sight revealed in seventeenth-century English poetry under the influence of the optical eye model. Navigating an array of renowned contemporary poets from Philip Sidney to Thomas Hobbes, Webster notes their emphasis on a quite nostalgic conception of true vision as unmediated transfer of information between matter and mind. In line with this definition, poetry was praised as a direct conduit between pictures material and mental, while artificial optical instruments were blamed for causing visual distortion. Nevertheless, it was often by comparing poetry to a flawless perspectival lens that these poets expressed their appreciation of its objective virtue.

In chapters 2 and 3, Webster discusses the nuanced interaction between similitude and optics in writings of contemporary experimental philosophers. She depicts the epistemic atmosphere in which members of the nascent Royal Society tried to cultivate a realistic look at nature by inventing more precise lenses and narrating observations in a plain style—and how they actually failed to achieve that. When exhausting their vision to chase the invisible, these virtuosos did not resist introducing imaginative analogy to complement their limited naked eyes and microscopic images. Metaphors were indeed incorporated into the repertoire of their visual technologies, collaborating with bodily and instrumental lenses. Like the ostensibly neutral “literary technology” that Steven Shapin in his article ‘Pump and Circumstance’ (1984) pinpoints to have comprised crucial fact-making strategies in Robert Boyle's laboratory, metaphors as explorative visual technology also carried certain values. Webster elaborates the imagery of lenses in Francis Bacon's “New Atlantis” (1626) and Margaret Cavendish's “Blazing World” (1666), where optics is used to create an experimental gaze at the exotica and manipulate surveillance and “visual control” (80) over it. By highlighting the imperialist and absolutist implications of the metaphorical lenses, she challenges the virtuosos’ claim of the ideological objectivity of their scopes.

In chapters 4 and 5, Webster looks at optical devices as imaginative access for seventeenth-century English philosophers to probing their spiritual world. She astutely observes that Kepler and Descartes's mechanical eye model, by defining the intrinsic fabric of the human eye as a camera obscura, divided the process of seeing into two phases. While the transfer of visual information of observed objects upon the retina was believed to be identical to projecting images onto a screen through a perspectival lens, the information processing behind the retina and in the brain remained mysteriously marvelous, implying the supreme and ineffable Godly knowing. In examining John Milton's experience of blindness, Webster further points out the essential role of religion in mapping his understanding of light and vision in the framework of eye structure resembling camera obscura. With light as the epiphany of God's grace, Milton and Isaac Newton pondered the infinity of the cosmos, his magnificent design. Milton's theological perspective led his conviction that God is omniscient since he possesses the highest perspective to look down to the whole celestial and terrestrial landscape. Newton's perspective was infinitesimal calculus. As with mathematicians exercising infinitesimal calculation to approach exact areas and slopes, God has his divine eye present at every smallest temporal-spatial unit, for which his knowledge is incomparable.

In chapter 6, Webster examines the seventeenth-century debate on the morality of vision aided by optical tools. While virtuosos spared no effort to distinguish their virtuous viewership from shameful voyeurism and their noble intellectual pursuit from superficial visual pleasure, critics like Aphra Behn denounced their practices as masculine invasions into the feminine Nature and its subjectivity. Through Behn, Webster casts light on the gendered anxiety in the early modern period about the phallic mechanical vision, in which lenses disguised the male observer's confinement of the observed woman through monitoring and assessing her chastity.

Anyone interested in early modern seeing can find delightful details in The Curious Eye. It is regrettable that, although engaging profoundly in the critical dialogue about observational subjectivity and objectivity in early modern science, Webster does not consult essential and recent studies in the field of history of science in much detail. For example, Lorraine Daston and Peter Galison's Objectivity (2007) and Daston and Elizabeth Lunbeck's Histories of Scientific Observation (2011) should not be disregarded. Besides, concentrating on a small community of intellectual elites inevitably leads to a lack of consideration of the pluralism of seeing. The curious eyes of individuals less literate and philosophical are also worth researching, especially the ways that they interacted with observations and corresponding visual inquiries of sophisticated eyes and ambitious lenses. However, Webster's thorough interpretation of these texts is convincing enough to argue that the absolutely objective seeing is itself an illusion. This is not exclusive to seventeenth-century English observers; the modern curious eye still embodies abundant analogy and imagination, and absorbs and impresses values from and upon what is seen.