No one before Platter and Kepler proposed retinal reception of an inverted visual image. The dominant tradition in visual theory, especially that of Alhazen and his Western followers, subordinated the intra-ocular geometry of visual rays to the requirement for an upright image and to preconceptions about the precise nature of the visual spirit and its part in vision. Henry of Langenstein and an anonymous glossator in the late Middle Ages proposed alternatives to Alhazen, including the suggestion of double (...) inversion of the image. Leonardo da Vinci was aware of both Alhazen's theory and Henry's contradiction, but perhaps not of the anonymous hypothesis of double inversion. Leonardo's visual ‘theory’ has more the character of a critique than of a theoretical alternative, and he did not transcend the medieval concept of visual spirit. (shrink)

“Although up to now the [visual] image has been [understood as] a construct of reason,” Kepler observes in the fifth chapter of his Ad Vitellionem Paralipomena, “henceforth the [visible] representations of objects should be considered as paintings [ picturae ] that are actual[ly projected] on paper or some other screen.” While not intended as a historical generalization, this claim nonetheless reflects historical reality. Virtually all visual theorists before Kepler did, in fact, conceive of optical images as subjective, not objective constructs (...) – or, to put it in modern terms, as virtual rather than real entities. By current lights, of course, the distinction between virtual and real images is both obvious and common-place: whereas the latter can be physically projected upon a screen, the former cannot. (shrink)

In the fifth book of his De aspectibus, the medieval Latin version of Ibn al-Haythamb al-Manir, Alhacen undertakes to determine precisely where a given ray of light will reflect to a given center of sight from a variety of convex and concave mirrors based on circular sections. As applied specifically to convex and concave spherical mirrors, this problem exercised several seventeenth-century thinkers, Christiaan Huygens foremost among them, and in that context it soon became known as Alhazens solution (or solutions) of (...) this problem is deficient in comparison to that of Huygens and later mathematicians. It is my purpose in this paper to show by reconstruction that in fact, far from deficient in any absolute sense, Alhacen’s approach to this problem was remarkably ingenious and elegant in its conceptual simplicity. (shrink)

Although numerous studies have been conducted on the Optics of Alhazen, and on its reception, assimilation and maturation within the course of development of the perspectivae traditions in the history of science and art, ambiguities do hitherto still surround the epistemological and ontological entailments of his theory of visual perception. In addressing this question, our inquiry herein is principally philosophical in scope and our textual reading combines exegesis with hermeneutics. While we observe the delicate procedures of historiography and philology, (...) we do not unguardedly assume that they are exhaustive of all rigorous methods of thoughtful investigation. Moreover, in heeding the internal coherence of Alhazen's text, we do not simply lock his views within reductive contextual chronologies, or readily confine them to epochal matters of textual transmission. Our endeavour is therefore not exclusively set in view of serving the purposes of archival documentation, even if we preserve a thorough and sound sense of historicity. We ultimately recognize the philosophical pertinence of numerous subtle leitmotifs within Alhazen's thinking that speak to us in an effective timely manner, which is significantly relevant in its attuned bearings to the thrust of phenomenological theories of perception. (shrink)

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This article seeks the origin, in the theories of Ibn al-Haytham (Alhazen), Descartes, and Berkeley, of two-stage theories of spatial perception, which hold that visual perception involves both an immediate representation of the proximal stimulus in a two-dimensional ‘‘sensory core’’ and also a subsequent perception of the three dimensional world. The works of Ibn al-Haytham, Descartes, and Berkeley already frame the major theoretical options that guided visual theory into the twentieth century. The field of visual perception was the first (...) area of what we now call psychology to apply mathematics, through geometrical models as used by Euclid, Ptolemy, Ibn al-Haytham, and Descartes (among others). The article shows that Kepler’s discovery of the retinal image, which revolutionized visual anatomy and entailed fundamental changes in visual physiology, did not alter the basic structure of theories of spatial vision. These changes in visual physiology are advanced especially in Descartes' Dioptrics and his L'Homme. Berkeley develops a radically empirist theory vision, according to which visual perception of depth is learned through associative processes that rely on the sense of touch. But Descartes and Berkeley share the assertion that there is a two-dimensional sensory core that is in principle available to consciousness. They also share the observation that we don't usually perceived this core, but find depth and distance to be phenomenally immediate, a point they struggle to accommodate theoretically. If our interpretation is correct, it was not a change in the theory of the psychology of vision that engendered the idea of a sensory core, but rather the introduction of the theory into a new metaphysical context. (shrink)

Contents Acknowledgements vii Illustrations ix Preface xi Further Bibliography of A.C. Crombie xiii 1 Designed in the Mind: Western visions of Science, Nature and Humankind 1 2 The Western Experience of Scientific Objectivity 13 3 Historical Perceptions of Medieval Science 31 4 Robert Grosseteste 39 5 Roger Bacon [with J.D. North] 51 6 Infinite Power and the Laws of Nature: A Medieval Speculation 67 7 Experimental Science and the Rational Artist in Early Modern Europe 89 8 Mathematics and Platonism in (...) the Sixteenth-Century Italian Universities and in Jesuit Educational Policy 115 9 Sources of Galileo Galilei’s Early Natural Philosophy 149 10 The Jesuits and Galileo’s Ideas of Science and of Nature [with A. Carugo] 165 11 Galileo and the Art of Rhetoric [with A. Carugo] 231 12 Galileo Galilei: A Philosophical Symbol 257 13 Alexandre Koyré and Great Britain: Galileo and Mersenne 263 14 Marin Mersenne and the Origins of Language 275 15 Le Corps à la Renaissance: Theories of Perceiver and Perceived in Hearing 291 16 Expectation, Modelling and Assent in the History of Optics: i, Alhazen and the Medieval Tradition; ii, Kepler and Descartes 301 17 Contingent Expectation and Uncertain Choice: Historical Contexts of Arguments from Probabilities 357 18 P.-L. Moreau de Maupertuis, F.R.S. : Précurseur du Transformisme 407 19 The Public and Private Faces of Charles Darwin 429 20 The Language of Science 439 21 Some Historical Questions about Disease 443 22 Historians and the Scientific Revolution 451 23 The Origins of Western Science 465 Appendix to Chapter 10: 479 Sources and Dates of Galileos Writings [with A. Carugo] Pietro Redondi, Galileo eretico [with A. Carugo] Mario Biagioli, Galileo, Courtier Corrections to Science, Optics and Music in Medieval and Early Modern Thought 495 Index 497. (shrink)

The Age of Enlightenment is more global and complex than the standard Eurocentric Colonial Canon narrative presents. For example, before the advent of unscientific racism and the systematic negligence of the contributions of Others outside of “White Europe,” Raphael centered Ibn Rushd (Averroes) in his Vatican fresco “Causarum Cognitio” (1511); the astronomer Edmund Halley taught himself Arabic to be more enlightened; The Royal Society of London acknowledged the scientific method developed by Ibn Al-Haytham (Alhazen). In addition, if we study (...) the Transatlantic texts of the late 18th century, it is not Kant, but instead enlightened thinkers like Anton Wilhelm Amo (born in present-day’s Ghana), Phillis Wheatley (Senegal region), and Toussaint L’Ouverture (Haiti), who mostly live up to the ideals of reason, humanism, universalism, and human rights. One obstacle to developing a more balanced presentation of the Age of the Enlightenment is the influence of colonialism, Eurocentrism, and methodological nationalism. Consequently, this paper, part II of two, will also deal with the European Enlightenment’s unscientific heritage of scholarly racism from the 1750s. It will be demonstrated how Linnaeus, Hume, Kant, and Hegel were among the Founding Fathers of intellectual white supremacy within the Academy. Hence, the Age of Enlightenment is not what we are taught to believe. This paper will demonstrate how the lights from different “Global Enlightenments” can illuminate paths forward to more dialogue and universalism in the 21st century. (shrink)

In lieu of an abstract, here is a brief excerpt of the content:110 HISTORY OF PHILOSOPHY History of Aesthetics, Vol. I. Ancient Aesthetics. By Wladyslaw Tatarkiewicz. Ed. J. Harrell. Trans. Adam and Ann Czerniawski. (The Hague-Paris: Mouton and Warszawa: PWN-Polish Scientific Publishers, 1970. Pp. vii-352.) History of Aesthetics, Vol. II. Medieval Aesthetics. By WladySlaw Tatarkiewicz. Ed. C. Barrett. Trans. R. M. Montgomery. (The Hague-Paris: Mouton and Warszawa: PWN-Polish Scientific Publishers, 1970. Pp. vii-315.) These two volumes of Tatarkiewicz' monumental history of (...) aesthetics, the third volume (to 1700) of which is now being prepared for press, have been reviewed already in the major aesthetic journals in Europe and America following their publication in Polish. Since Polish is not one of my languages, I can say nothing about the adequacy of the (rather obscured) translators and their work. The editors of both volumes have done their difficult work thoroughly, though the usual inconsistencies of spelling and such creep in. British spellings of judgement, centre, and colour, for example, appear in one part of a volume, while center, color, and judgment appear in another part. These are rare and not at all irksome details. On p. 220 of volume I, Aristotle has become a Stagiryte (sic). If the editors and translators actually re-checked all of those Greek, Polish and English texts--to say nothing of the Latin--they have earned a very large debt indeed. Again, my selective ignorance eliminates me from assessment. Tatarkiewicz' historical writing is surgical and Lacon-like. His major achievement lies in refraining from philosophical animadversions and for sticking strictly to his topic, no matter how tempting the theoretic distractions. Actually one expects a history of aesthetics to find the locus of aesthetic theory in the usual systematic frameworks of outstanding philosophers, but again Tatarkiewicz knows better than to try to provide these settings. His device is to stay exactly with the texts of authors, and to provide as much evidence for his statements as a printed work will allow. His scholarship is truly prodigious, and the work will live as reference for a long time to come. But it is more than a reference. There are some remarkable novelties included that bear mention. First of all, Tatarkiewicz' opening analysis of what must be included in a history of aesthetics is penetrating and convincing. In addition to the major "dualities" of aesthetics (beauty-art, subjective-objective aesthetics, psychological-sociological aesthetics, descriptive-prescriptive aesthetics, etc.) he simply accepts the necessity to find evidence of aesthetic history among statements by artists, among the inexplicit and inarticulate art works, in the vox populi and cultural actions of people. Thus the "evidence" he adduces will often displease the theoretical purist. Next, one is impressed by the great antiquity of some key issues that are being avidly pursued today. What is impressive is not that they are being repeated now, but that modern writers so rarely recognize (or acknowledge) their historical sources---or seem to care to. A careful study of this history might do much to reduce the growing volume in aesthetics----or at least to change the direction of emphasis significantly. One is surprised to note which figures emerge as of first rate importance in the history of aesthetics, important for different reasons. These figures stand out: Democritus, Plotinus, Aristotle, Vitruvius, the Pseudo-Dionysius, Johannes Scotus Erigena, to select only a few. The first Polish philosopher, Vitelo, anticipates much modern psychologizing in advancing the work of Alhazen. Ockham, not so surprising, contributes major advances, as do Augustine and Aquinas. BOOK REVIEWS 111 One fascinating item is the author's extensive account of the most violent and extended controversy in the history of aesthetics---the veneration of images and the disputes between the Iconoclasts and the Iconophiles. This sometimes physical battle raged for over 100 years! The Byzantine society, obviously, took art seriously. Tatarkiewicz' great labor is an object lesson in historiography and bibliographic technique. At one and the same time it demonstrates how much of value remains to be discovered by careful adherence to the detail of scholarship, while it also displays how much fruitful scholarship depends upon a brilliant and profoundly informed mind. Such a work, in short, could only have descended from a fully mature... (shrink)

The subject of "Seeing Physics" is our understanding of the physical universe as organized into 51 one thousand-word essays each anchored in a drawing that conveys a key idea. Each essay expands on the science of the drawing and places it in a broader human context. Many people have an interest in the latest in science and technology. But many, even among this group, do not understand basic principles from the 2600-year old intellectual tradition of physics. The old ideas are (...) still new to those who don't understand them. Some of the classic discoveries and theories Lemons discusses include Archimedes' Principle, Alhazen's early theory on the optics of vision and refracted rays, Oresme's Triangle, how Copernicus was able to discover heliocentricism, and Rontgen's accidental discovery of X-rays. (shrink)

In Aesthetics in Arabic Thought from Pre-Islamic Arabia through al-Andalus José Miguel Puerta Vílchez analyzes the discourses about beauty, the arts, and sense perception that arose within classical Arab culture from pre-Islamic poetry and the Quran (sixth-seventh centuries CE) to the Alhambra palace in Granada (fourteenth century CE). He focuses on the contributions of such great thinkers as Ibn Ḥazm, Avempace, Ibn Ṭufayl, Averroes, Ibn ʻArabī, and Ibn Khaldūn in al-Andalus, and the Brethren of Purity, al-Tawḥīdī, al-Fārābī, Avicenna, Alhazen, (...) and al-Ghazālī in the East. The work also explores literary criticism, calligraphy, music, belles-lettres (adab), and erotic literature, and highlights the contribution of Arab humanism to shaping the field of Aesthetics in the West. (shrink)

La theorie ockhamienne de la connaissance evidente porte sur certains aspects causaux qui ont lieu dans l'intellect et produisent l'assentiment a certaines propositions. Les propositions connues de facon evidente sont les propositions connues par les sens, celles dont la connaissance depend de la seule apprehension des concepts et, de facon indirecte, les conclusions des raisonnements. Dans tous ces cas, l'assentiment a la proposition est cause naturellement par l'apprehension des termes. Si le Venerabilis Inceptor suit une certaine tradition dans la reconnaissance (...) des traits communs a ces situations, l'assentiment immediat et universel, il en offre une explication qui lui est propre, par la causalite naturelle. Cette explication se deploie dans une theorie de la scientia. Par scientia, il faut entendre a la fois le savoir et la science. Il s'agit, d'une part, d'une theorie sur un discours organise en syllogismes, ayant une certaine dynamique cognitive et constitue par des qualites mentales singulieres et, d'autre part, d'une theorie de la rationalite, construite autour des processus causaux naturels. Ce livre presente ce complexe theorique ockhamien et ses rapports avec les theories de Robert Grosseteste, Alhazen, Jean Duns Scot et Jean Buridan. (shrink)

In this chapter I examine past and recent theories of unconscious inference. Most theorists have ascribed inferences to perception literally, not analogically, and I focus on the literal approach. I examine three problems faced by such theories if their commitment to unconscious inferences is taken seriously. Two problems concern the cognitive resources that must be available to the visual system (or a more central system) to support the inferences in question. The third problem focuses on how the conclusions of inferences (...) are supposed to explain the phenomenal aspects of visual experience, the looks of things. Finally, in comparing past and recent responses to these problems, I provide an assessment of the current prospects for inferential theories. (This paper is reprinted in Hatfield 2009, Perception and Cognition: Essays in the Philosophy of Psychology, Clarendon Press, 124-152.). (shrink)

In this expository article, a presentation is given of A.C. Crombie's life work in the history of science, Styles of Scientific Thinking in the European Tradition. The History of Argument and Explanation in the Mathematical and Biomedical Sciences and Arts (1994). The importance of this work for the philosophy of science and epistemology is comparable to the more renowned work of the 1960's and '70s, but threatens to be paradoxically overlooked because of its gigantic proportions. (No thorough study of the (...) book appeared up to now.) Crombie's earlier work started from a provocative version of continuism in the debate about the rise of modern science, ascribing the origin of the experimental tradition to methodological forebears in the thirteenth century (Grosseteste). Rather than revivifying this quarrel now, Crombie has offered us an emergentist picture of the rise of six subsequent major styles of science (using grand units of analysis) from the Greeks up to Darwin. These styles of thinking are superimposed upon another in that the definite breakthrough of each next style is consequent upon the recognition of the proper limits of the full grown previous style. In a first group, Crombie assembles three major styles for revealing regularities in individual phenomena, i.e. where the consideration of the collective to which the phenomenon belongs is not required for recognizing the regularity. Here we have (S1) the ancient style of postulating principles and entities according to a more or less apriorical evidence type or in axiomatic fashion; (S2) the experimental tradition from Alhazen up to Newton, and (S3) the style of hypothetical modelling, combining the former two in the vein of the rational artist as an (ultimately, also cognitive) engineer. In a second group the styles dealing with regularities discoverable only in a collectivity of phenomena are dealt with. Here we have the (S4) probabilistic style superimposed on the classical picture of rationality made up by the achieved styles in the first group. Then (S5) the taxonomic style is ready to be combined, finally, with S4, in order to discover the statistical economy of living nature in (S6), the 'genetic' style, culminating in Darwin's history of nature (which was to be expected). On the other hand, the latter style is traced back to the 16th and 17th century project of a history of languages and culture, of knowledge, and of mankind (which is a more surprising connection made by Crombie). In a final section some philosophical remarks are made regarding Crombie's project; mainly with respect to the larger perspective, in Crombie's terms, of an 'intellectual anthropology', or alternatively, in terms of a 'comparative epistemology'. Also the absence of a real analysis of the very concept of style is noted. (shrink)

This paper focuses on the methodological issues related to the obstacles and potential horizons of approaching the philosophical traditions in Islam from the standpoint of comparative studies in philosophy, while also presenting selected case-studies that may potentially illustrate some of the possibilities of renewing the impetus of a philosophical thought that is inspired by Islamic intellectual history. This line of inquiry is divided into two parts: the first deals with questions of methodology, and the second focuses on ontology and phenomenology (...) of perception, by way of offering pathways in investigating the history of philosophical and scientific ideas in Islam from the viewpoint of contemporary debates in philosophy. A special emphasis will be placed on: (a) interpreting the ontology of the eleventh century metaphysician Ibn Sīnā (known in Latin as: Avicenna; d. 1037 CE) in terms of rethinking Heidegger’s critique of the history of metaphysics, and (b) analyzing the philosophical implications of the theory of vision of the eleventh century polymath Ibn al-Haytham (known in Latin as Alhazen; d. ca. 1041 CE) in terms of reflecting on Merleau-Ponty’s phenomenology of perception. (shrink)

The somewhat deflating conclusion of Simon A. Gilson's meticulous examination of Dante's incorporation of the science of optics and theories of light is that the poet was considerably less well read than we have been giving him credit for.Gilson's book is divided into two parts: the first, dealing with the science of optics, contains four chapters; the second, dealing with theories of light, contains three. Each of these parts is devoted to debunking a tendency in Dante scholarship to attribute to (...) a particular scientific or philosophical movement a marked influence on his work. In the first part Gilson maintains that Dante's use of the science of optics does not—as others, most forcefully and influentially Alessandro Parronchi, have argued—rely specifically on knowledge of the authors of the perspectivae—detailed treatises on optics that placed the influence of light rays at the origin of terrestrial phenomena—that is, on such thinkers as Alhazen, Roger Bacon, and Robert Grosseteste. Rather, Gilson contends that Dante could easily have come by the requisite expertise concerning this science through contact with the more popular and widely known doctrines of such Arab interpreters of Aristotle as Avicenna and Averroës and the commentaries of Albert the Great and Thomas Aquinas. He demonstrates the plausibility of this contention by way of a comparative analysis of the doctrines of the perspectivists and the Arab interpreters. This analysis is followed by a chapter devoted to optics and vision in Dante's earlier poetry.The two following chapters cover, respectively, topics such as blinding, optical illusions, and visual error in Dante's Commedia and the themes of reflection, mirrors, and meteorological optics, also in the Commedia, a work that Gilson specifies as having nevertheless gone beyond the more limited sources of the earlier poetry. In the third chapter Gilson's analysis achieves a welcome degree of insight into the poet's originality: here Gilson shows how Dante incorporates the scientific knowledge of his day in order to establish a set of limits that circumscribe human action in the physical world but that must be overcome in the course of the pilgrim's journey through his imaginative world. Such moments provide a refreshing alternative to an otherwise rather positivistic view of scientific knowledge as a compendium of facts and sources one either has or has not read. One cannot help but think that researchers in the field of the history of science might be most interested in the imaginative contributions of a specifically poetic knowledge, especially in an age in which the distinction between “hard” and “soft” science was not accorded the kind of unquestioned respect it currently receives.In the second part Gilson, continuing his debunking analysis, argues that the scholarship on Dante and his use of theories of light has remained captivated by the notion of “the metaphysics of light.” This term, Gilson claims, has been used to unify and oversimplify a rather diverse group of doctrines concerning the nature of light and its relation to knowledge, vision, God, and being. Against the grain of the traditional critical trend, Gilson maintains that Dante's thought has nothing in common with the proper metaphysics of light of a Grosseteste—who identifies light as the primary element of being—and that Dante would have had relatively little contact with Neoplatonic theories of emanation. Again, according to Gilson, in applying the imagery of light to his poetic themes, Dante would have had readily available models in the popular theological light imagery of his time; his use of light in the description of the Empyrean is, Gilson states, perhaps the best example of Dante's relative independence from any limited set of sources.Whether Gilson's informative examination of Dante's relative dependence on sources should be understood as liberating the poet from the anxiety of scientific influence remains, however, an open question. Whatever the extent or depth of any enumeration of those sources, it is the moment of creation that astonishes. (shrink)