Encyclopedia of the History of Arabic Science - Vol. 2

By Roshdi Rashed; Régis Morelon | Go to book overview

20

The emergence of physiological optics

GÜL A.RUSSELL

'There is more to seeing than meets the eyeball'

N.R. Hanson


INTRODUCTION

In the history of physiological optics, the correct identification of the site of the projections from the retina in the striate cortex by Munk (1839-1912) marked the end of an era. Subsequently the task changed from searching for the location of perception to determining the nature of its central mechanisms, or from 'where' in the brain to 'what' occurred in the visual cortex that enabled us to perceive the world. 1

Intellectually, the concept of point to point organization of visual centres in the cerebral cortex had its historical antecedents. Descartes (1596-1650) was credited with a punctate remapping of the retinal image along the central pathways. Underlying his belief that the optic tract projected to the pineal gland, was the notion of central re-projection. 2 Prior to Descartes, Kepler (1571-1630) had established that an inverted image was formed in the eye by means of the lens focusing the rays of light from each point on the surface of the object to a corresponding point on the retina. Diverging from previous theories, based on the work of such anatomists as Felix Platter (1536-1614), Kepler shifted the emphasis from the lens onto the retina as the light-sensitive surface in the eye. He dissociated the analysis of its optical mechanism from the problematic issue of how an inverted retinal image could be reconciled with a veridical perception of the world. 3

Historically the very formulation of the notion of a projected image is of crucial significance. It provided a radical solution to the persistent ancient problem of how the external world was perceived through the sense of sight. By bringing together the physics of light and the anatomy of the eye, such

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Encyclopedia of the History of Arabic Science - Vol. 2
Table of contents

Table of contents

  • Title Page iii
  • Contents v
  • 10 - Numeration and Arithmetic 331
  • 11 - Algebra 349
  • Notes 370
  • 12 - Combinatorial Analysis, Numerical Analysis, Diophantine Analysis and Number Theory 376
  • 13 - Infinitesimal Determinations, Quadrature of Lunules and Isoperimetric Problems 418
  • 14 - Geometry 447
  • Notes 494
  • 15 - Trigonometry 495
  • 16 - The Influence of Arabic Mathematics in the Medieval West 539
  • 17 - Musical Science 581
  • 18 - Statics 614
  • 19 - Geometrical Optics 643
  • 20 - The Emergence of Physiological Optics 672
  • 21 - The Western Reception of Arabic Optics 716
  • Notes 728
  • Bibliography 730
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