Philosophers and psychologists often assume that mirror reflections are optical illusions. According to many authors, what we see in a mirror appears to be behind it. I discuss two strategies to resist this piece of dogma. As I will show, the conviction that mirror reflections are illusions is rooted in a confused conception of the relations between location, direction, and visibility. This conception is unacceptable to those who take seriously the way in which mirrors contribute to our experience of the (...) world. My argument may be read as an advertisement of the neglected field of philosophical catoptrics, the philosophical study of the optical properties of mirrors. It enables us to recast familiar issues in the philosophy of perception. (shrink)

This paper approaches some aspects concerning 16th century optics, particularly, the studies on lenses by Giambattista della Porta in Magiae naturalis libri XX, De refractione optices parte libri novem and De telescopio. An analysis of these works shows that Della Porta sought to explain how lenses work within the traditional theoretical frameworks. Since optics was one of the fields of knowledge that a magician should take into account in his practice, in this paper we point out to the relationship between (...) experiment and mathematics in Della Porta’s natural magic. (shrink)

Summary When dealing with philosophical questions such as the choice of a world system or the substance of heaven, some sixteenth-century astronomers, including Tycho Brahe and Christophe Rothmann, devised more accurate experimental setups so that they could refine their celestial observations. With this desire to listen to nature arose new questions, in particular that of atmospheric refractions, the understanding and resolution of which became decisive to guarantee the best accuracy. However, to solve such practical problems, it was necessary to consider (...) their philosophical and theological background, as well as the knowledge of optics inherited from the medieval period. We examine this heritage and its transmissions through the works of Peter Ramus's assistants, especially Jean Pena and Friedrich Risner. From this first survey, we try to analyse the lively debate on atmospheric refractions in the late sixteenth and early seventeenth centuries by exploring the argumentative structure, the philosophical background, and the epistemological grounds of the discourse of authors such as Tycho Brahe, Christoph Rothmann, and Johannes Kepler. (shrink)

This paper argues that Kepler considered his work in optics as part of natural philosophy and that, consequently, he aimed at change within natural philosophy. Back-to-back with John Schuster’s claim that Descartes’ optics should be considered as a natural philosophical appropriation of innovative results in the tradition of practical and mixed mathematics the central claim of my paper is that Kepler’s theory of optical imagery, developed in his Paralipomena ad Vitellionem (1604), was the result of a move similar to Descartes’ (...) by Kepler. My argument consists of three parts. First, Kepler borrowed a geometrical model and experiment of optical imagery from the mélange of mixed and practical mathematics provided in the works of the sixteenth-century mathematicians Ettore Ausonio and Giovanni Battista Della Porta. Second, Kepler criticized the Aristotelian theory of light and he developed his own alternative metaphysics. Third, Kepler used his natural philosophical assumptions about the nature of light to re-interpret the model of image formation taken from Della Porta’s work. Taken together, I portray Kepler’s theory of optical imagery as a natural philosophical appropriation of an innovative model of image formation developed in a sixteenth-century practical and mixed mathematical tradition which was not interested in questioning philosophical assumptions on the nature of light. (shrink)