Własność duszy, ciała czy światła? Od średniowiecznych rozważań do nowożytnych koncepcji widzenia

Abstract

Vision is the faculty by which the visible external world is perceived. The primary task of all theories of vision was to explain how useful information about external world was recovered from the changing retinal image. Theorists of vision had proposed various accounts of the nature of the processing responsible for our perception of external objects. The Latin world considered visual process issues generally based on Greek philosophers theories of vision. Saint Augustin of Hippo maintained that spiritual light was the internal illuminant of the ideal forms and physical light was considered to be analogous to this. The XI and XII centuries conceptions of nature did not radical transformed solution of vision problem. Albertus Magnus (Albert the Great) elaborated extensively on the traditional brain localization theory and believed that a close correlation existed between brain function and the various psychological abilities: the signals generated by a given object corresponded to a different sensory system species and reached the respective sense organs (contained a specific spiritus sensibilis) by means of a medium located in the extra-personal space. The spiritus visibilis found in the eye was instrumental in transforming the signals produced by material object species into a physiological process. The next centuries theories of vision were molded both by scientific work and artistic discoveries. In Robert Bacon’s theory species (first natural effect of any agent) issued in all direction from every point on the visible object and reach all point on the surface of eye. Witelo regarded light as one special case of natural action that reveals the mode of all other natural sections. Blasius of Parma and Henry of Langenstein did not doubt that vision was produced by interior rays, which could be geometrical analyzed. Nicolas Oresme proved that vision occurred through the reception of rays emitted from the visible object. Leonardo da Vinci draw the ventricular system and created the sophisticated model of vision. In William of Ockham’s theory the vision occurred because it was the nature of the object to act on the visual power and of the visual power to perceive the object. Optic theorists (especially in the seventeenth century) created the geometric models of vision and construe visual processing as a species of mathematical calculation or questioned the psychological reality of these models. Rene Descartes postulated that light acted on the retina by a direct mechanical effect leading to ‘vibration’ of the optic nerve fibers. Johannes Kepler formulated the basic principle of photometry. According to Felix Plater suggestion, that retina was the sensitive organ of vision, Kepler created the correct description of image formation on it. He considered, that refracted rays could not be ignored, visual theory had to be continued with anatomical facts and he added some detail concerning the structure and properties of the retina. The vision occurred through the picture of the visible things formed on concave surface of retina. The discovery of the visual cortex researched by Herman Munk and Sigmund Exner sketch’s of human visual areas moved the theories of vision to the level of cognition and psychological aspects of perception.