Mirrors and Mirroring. From Antiquity to the Early Modern Period. 6.-7. October 2017 Program and Abstracts (original) (raw)

Claudius Ptolemy (ca. AD 100 – ca. 170) and Giambattista Della Porta (ca. 1535 –1615): Two Contrasting Conceptions of Optics.

We address the phenomenon of reflection in concave spherical mirror in two contrasting approaches to optics. In his Optics (ca.165) Ptolemy applied the cathetus principle as a regulative means for explaining qualitatively effects related to visual perception in concave spherical mirror. By contrast, Della Porta's study of reflection in concave spherical mirror in Bk. 17, Ch. 4 of his Magia naturalis (1589) and De refractione (1593), was based on the assumption that there is a reciprocal relation between reflection in concave spherical mirror and refraction in glass sphere. We juxtapose these two studies and draw several philosophical lessons from the comparison between these two practices with a view to throwing into relief the fundamental differences in their respective conceptions of optics.

Christoph Scheiner's The Eye, that is, The Foundation of Optics (1619): The Role of Contrived Experience at the Intersection of Psychology and Mathematics

Elusive Phenomena, Unwieldy Things: Historical Perspectives on Experimental Control, 2024

Accounts of the development of experimental methods (including controls, broadly understood) in the seventeenth century generally overlook Aristotelians. Until recently the consensus was that, because of the art-nature distinction and a focus on final causes, Aristotelianism had significant issues incorporating experiments and contrived experiences into the natural sciences, including “middle” sciences such as optics. I argue that this picture relies, in part, on a misreading of Aristotle’s Posterior Analytics a treatise on epistemology. In particular, book 2 chapter 19 has been seen as an account of how Aristotle justified grasping the principles of a science based on so-called “common sense” experience. Recent Aristotle scholars have challenged this, instead arguing that this notorious chapter on “Aristotelian induction” is, instead, just a general psychological description of how sensation leads to memory, from memory to experience, and from there to the grasping the universal first principles of either an art or a science. The epistemic justification for those principles, for any particular art or science, is rather more complex and domain-specific. What, then, did early modern Aristotelians in fact present as an account of how to actually grasp the first principles of any particular science? This contribution examines the Jesuit polymath Christoph Scheiner’s 1619 work, The Eye, that is, The Foundation of Optics, in which he argues for the revolutionary position that the retina, not the crystalline lens, is the seat of visual sensation. Scheiner relies on first-hand anatomy, contrived experiences, and experiments to establish at the axioms of optics, but I argue that his Aristotelianism presented no special obstacles to this. What Scheiner means by sensation, memory, and experience in this treatise are complex, and Scheiner’s implementation of control practices is rather sophisticated for the time. In this he was part of a general trend in the seventeenth century, most noticed in anti-Aristotelians such as Francis Bacon, in which we see scientific methodology being examined critically and experimental precepts, including control strategies, developed explicitly.

The Visual Process: Immediate or Successive? Approaches to the Extramission Postulate in 13th-Century Theories of Vision (2020)

In: Medieval Perceptual Puzzles: Theories of Sense-Perception in the 13th and 14th Centuries, ed. by E. Baltuta (Brill), 2020

Is vision merely a state of the beholder’s sensory organ which can be explained as an immediate effect caused by external sensible objects? Or is it rather a successive process in which the observer actively scanning the surrounding environment plays a major part? These two general attitudes towards visual perception were both developed already by ancient thinkers. The former is embraced by natural philosophers (e.g., atomists and Aristotelians) and is often labelled “intromissionist”, based on their assumption that vision is an outcome of the causal influence exerted by an external object upon a sensory organ receiving an entity from the object. The latter attitude to vision as a successive process is rather linked to the “extramissionist” theories of the proponents of geometrical optics (such as Euclid or Ptolemy) who suggest that an entity – a visual ray – is sent forth from the eyes to the object. The present paper focuses on the contributions to this ancient controversy proposed by some 13th-century Latin thinkers. [...]

Attention, Perceptual Content, and Mirrors: Two Medieval Models of Active Perception in Peter Olivi and Peter Auriol (2017)

Filosofický časopis (Special Issue: Perception in Scholastics and Their Interlocutors), 2017

In the paper I argue that medieval philosophers proposed several notions of the senses’ activity in perception. I illustrate the point using the example of two Franciscan thinkers – Peter Olivi (ca. 1248–1298) and Peter Auriol (ca. 1280–1322). Olivi’s notion of active perception assumes that every perceptual act demands a prior focusing of the mind’s attention. Furthermore, Olivi is partially inspired by the extramissionist theories of vision and reinterprets the notion of a visual ray postulated by them as a useful model for explaining attention and attentional shifts. In Auriol’s view, perception is active because it participates in producing a perceptual content. The senses not only receive information from the environment, they also actively process it and, in Auriol’s words, put the external object into apparent being. The peculiar feature of Auriol’s account is his obvious tendency to conceive perceptual content as both dependent on our perceptual activity and external to the senses. Finally, I consider the two theories in the context of mirror perception – while Olivi focused on the ability of mirrors to switch attention’s direction, Auriol investigated the metaphysical nature of mirror images.

Optical Illusion: A Perspective on the Sense of Sight in Early Modern Philosophical Thinking

On account of the 17 th century optics, the Scholastic theory of the unity of senses has been viewed in a critical manner. A true revolution was engaged by the new theory of vision initiated by Johannes Kepler who had a great influence on the philosophical thinking of that time, especially on Descartes' and Hobbes' works. Being the first who applied the camera obscura principle to reveal the mechanisms of sight, Kepler emphasized the importance of the subject in the process of imaging, ultimately leading to the idea of an external reality that subjectivized itself. The new theory of vision has been speculated by Early Modern philosophers in support of the idea that the senses are deceptive. From science and philosophy, the idea of deceiving senses penetrated into Baroque painting and architecture, performing the illusory effect of trompe l'oeil in which two-dimensional images would be perceived as three-dimensional ones. Thus, science, philosophy and especially art devel...

Adam's Spectacles: Nature, Mind and Body in the Age of Mechanism

This thesis explores the ways in which the mind-body relationship was problematized after Descartes, in the context of the scientific revolution in the second half of the seventeenth century, both in France and in England. It is an attempt to historicize ongoing debates within the cognitive sciences and the philosophy of mind about the problem of consciousness. By reconstructing a history of the status of the self-aware, human mind through the history of scientific explanation, I address the question of whether or not a complete, scientific explanation of higher consciousness is possible. Adopting a conceptual, rather than chronological framework, I concentrate on figures who played a role in the scientific, theological and philosophical debates of their day, rather than on the subjects studied in modern philosophy curricula, although Descartes, Locke and Malebranche are present throughout. Part I focuses mainly on post-Cartesian views on dualism. Part II relates these theoretical debates to discussions about the nature of scientific enquiry. The thesis begins with Fellows of the Royal Society, including William Holder and George Dalgarno, who discussed the possibility of devising a language for the deaf, as well as the nature of language, ideas and perception. Orthodox followers and later interpreters of Descartes like Gérauld de Cordemoy, François Fenelon and Louis de La Forge also wrote about these issues. Debates over the Cartesian 'beast-machine' thesis and over definitions of reason and instinct, are considered next, by looking at the works of Ignace-Gaston Pardies, Antoine Dilly and Pierre Bayle. These discussions were a manifestation of the need to define human nature apart from its physical embodiment. Part II begins with a consideration of the various ways that sceptical traditions informed programmes of scientific enquiry on both sides of the Channel, through the writings of Joseph Glanvill and Bernard de Fontenelle, among others. Arguments about teleology and about the relation between anatomical form and physiological function by thinkers and natural philosophers such as Robert Boyle, Nicolaus Steno and Thomas Willis are treated in the next chapter. These enquiries prepare the ground for the final chapter, which considers texts by physicians and anatomists, including Claude Perrault and Guillaume Lamy, on the physiology of the 'corporeal soul'. 3

Perception and its Objects.

Perception and the Inhuman Gaze: Perspectives from Philosophy, Phenomenology, and the Sciences Ed. A. Daly, F. Cummins, J. Jardine, D. Moran. New York: Routledge, 109-127, 2020

'The Gaze' as a dimension of visual perception focuses attention on the perceived rather than the per-ceiver, and underlines the idea that the 'object' of perception must be understood relationally, and as primarily affective. This contrasts with the Cartesian-derived view based on an underlying separation of subject and object which makes it possible to adopt a 'spectator' view of knowledge. This paper explores aspects of the origins and consequences of these contrasting views showing the importance of Merleau-Ponty's Umweltian-inspired notion of embodied and enactive intentionality in reconceptu-alising the view of nature and of science that is dictated by the spectator view.