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)

The eighth-century Latin manuscript Milan, Veneranda Biblioteca Ambrosiana, L 99 Sup. contains fifteen palimpsest leaves previously used for three Greek scientific texts: a text of unknown authorship on mathematical mechanics and catoptrics, known as the Fragmentum Mathematicum Bobiense (three leaves), Ptolemy's Analemma (six leaves), and an astronomical text that has hitherto remained unidentified and almost entirely unread (six leaves). We report here on the current state of our research on this last text, based on multispectral images. The text, incompletely (...) preserved, is a treatise on the construction and uses of a nine-ringed armillary instrument, identifiable as the “meteoroscope” invented by Ptolemy and known to us from passages in Ptolemy's Geography and in writings of Pappus and Proclus. We further argue that the author of our text was Ptolemy himself. (shrink)

ArgumentA Catoptrica attributed to Euclid appears in manuscripts amongst treatises dealing with elementary astronomy. Despite this textual background, the treatise has always been read literally as a theory of mirrors, and its astronomical significance has gone unnoticed. However, optics, catoptrics, and astronomy appear strongly intermingled in sources such as, amongst others, Geminus, Theon of Smyrna, Plutarch and Cleomedes. If one compares the optical reasoning put forward in these sources to account for the formation of moonlight with arguments of Catoptrica, (...) one is able to shed new light on several principles and propositions of Catoptrica, some of which had been deemed corrupt, meaningless, and obscure. Moreover, the present analysis offers a glimpse at the context of a specific stage in the evolution of ancient catoptrics: Whether literally or by analogy, several of its results appear to have been set against a wider astronomical background, which explains the inclusion of Catoptrica in the group of texts loosely defined as “little astronomy.”. (shrink)

This publication of al-Kindī's Optics and Catoptrics provides editio princeps and the first translation of three books including the Rectification of Euclid's Optics hitherto unknown. In this book, the reader will find genuine and new information about Greek and Arabic optics and catoptics.

Among the writings devoted to the reflection of “visual” and solar rays on various mirrors, there are two that preceded many others and that occupy a central position in the history of catoptrics: one is attributed to Euclid, the other to Ptolemy. To these two names, we add a third, hitherto unknown, Thiasos. In this article, we take up the textual and conceptual history of this catoptric research tradition.