Cover -- Half-title -- Title -- Copyright -- Dedication -- Contents -- Acknowledgements -- 1 Introduction -- 1.1 Roots of the duplicity theory of vision: Ancient Greeks -- 1.2 Further development of the duplicity theory -- Part I The development of the basic ideas of the duplicity theory from Newton to G. E. Müller -- 2 The Newton tradition -- 2.1 Newtons universal colour theory -- 2.2 An alternative to Newtons theories of light and colour -- 2.3 Phototransduction in the retina and signal transmission to the brain:Newtons speculations -- 2.4 Newton's gravitation principle applied to colour mixture data -- 2.5 Conclusions -- 2.6 Young's colour theory: three instead of seven primaries -- 2.7 Maxwell: triplicity of colour vision proved -- 2.8 Helmholtz: the Young-Helmholtz colour theory -- 3 The Schultze tradition -- 3.1 The duplicity theory of Max Schultze -- 3.2 Evidence in favour of the theory -- 3.3 One or several types of cone? -- 3.4 Phototransduction is photochemical in nature: Boll and Khne -- 3.5 Boll: discovery of rhodopsin as a visual photopigment -- 3.6 Kuhne: several photochemical substances in the retina -- 3.7 Phototransduction of rhodopsin -- 3.8 Parinaud and Konig: early reformulations of the duplicity theory -- 3.9 The duplicity theory of Parinaud -- 3.10 Konig: rhodopsin is the mediator of night vision - a conclusive proof -- 3.11 The duplicity theory of Konig -- 3.12 The duplicity theory of von Kries -- 1. Lights that match in day vision may differ in twilight vision: the Purkinjephenomenon. -- 2. Anatomical interpretation of the theory. Cones and Rods. Uniquenessof the fovea. Rhodopsin. -- 3. Isolation of twilight vision. Congenital, total colour-blindness.Nyctalopia. On comparative anatomy. -- 3.13 An attempt to unify the theories of Schultze and Young-Helmholtz -- 4 The Goethe tradition: the phenomenological approach.

4.1 Phenomenological analysis may reveal underlying material processes -- 4.2 The colour theory of J..W. von Goethe -- 4.3 Goethe's contribution -- 4.4 The colour theory of Ewald Hering -- 4.5 Experiments in support of Hering's colour theory -- 4.6 Contributions of Hering -- 5 The colour theories of Armin Tschermak and George Elias Mller -- 5.1 The colour theory of Tschermak -- 5.2 The duplicity theory of G..E. Muller -- 5.2.1 G..E. Muller's speculation on the phototransduction in rods -- 5.2.2 Cones may inhibit regeneration of rhodopsin -- 5.2.3 Rods subserving chromatic colour vision -- 5.2.4 Three types of cones and five pairs of opponent processes -- 5.2.5 Activation of opponent processes by P1, P2 and P3 -- 5.2.6 The P1 system -- 5.2.7 The P2 system -- 5.2.8 The P3 system -- 5.3 Evaluation of G..E. Muller's colour theory -- Part II The development of the duplicity theory from 1930-1966 -- 6 The duplicity theory of Polyak -- 6.1 Trichromacy of colour vision explained by three types of bipolar cell -- 6.2 Midget ganglion cells as synthesizers -- 6.3 The specific fibre-energy doctrine questioned -- 6.4 Applications of Polyak's colour theory -- 6.5 Common pathways of rods and cones -- 6.6 Explanations of acuity and sensitivity differences between rods and cones -- 6.7 The functional potentials of the synaptic arrangement -- 7 Investigations of H..K. Hartline and S..W. Kuffler -- 7.1 The electrical responses to light stimuli in single optic nerve fibres -- 7.2 The electrical responses in single optic nerve fibres of Limulus -- 7.3 The electrical responses in single optic nerve fibres of the frog -- 7.4 Receptive field organization of rods and cones: Kuffler's investigation -- 8 The duplicity theory of R. Granit -- 8.1 Supporting evidence for the duplicity theory from the ERG technique -- 8.2 The dominator-modulator theory.

8.2.1. The trichromatic colour theory challenged -- 8.3 Schultze's duplicity theory challenged -- 9 Contributions of E..N. Willmer, P. Saugstad & A. Saugstad, and I. Lie -- 9.1 The duplicity theory of Willmer -- 9.1.1 Colour vision explained by two types of rod and one type of cone -- 9.1.2 Evidence supporting Willmer's duplicity theory -- 9.1.3 Reformulation of Willmer's duplicity theory -- 9.1.4 Evidence supporting rods as 'blue' primaries -- 9.1.5 Evidence opposing rods as 'blue' primaries -- 9.2 Saugstad and Saugstad: Evaluation of Schultzes duplicity theory -- 9.2.1 Reformulation of Schultze's duplicity theory -- 9.2.2 Evidence in support of Schultze's duplicity theory -- 9.2.3 Evidence against Schultze's duplicity theory -- 9.3 Ivar Lie: interactions between rod and cone functions at mesopic intensity -- 9.3.1 Psychophysical experiments -- 9.3.2 The colour-mixing hypothesis -- 9.3.3 An alternative explanatory model -- 10 Status of the duplicity theory in the mid 1960s and its further development -- 10.1 Elaboration and revision of the two most basic assumptions of Schultze's duplicity theory -- Part III Chromatic rod vision: a historical account -- 11 Night vision may appear bluish -- 12 Mechanisms of chromatic rod vision in scotopic illumination -- 12.1 All principle hues may be observed in scotopic vision -- 12.2 Scotopic contrast colours are triggered by rod signals -- 12.3 Scotopic contrast colours depend on selective chromatic adaptation of cones -- 12.4 Scotopic hues explained -- 12.5 Modifications of Hering's opponent colour theory -- 13 Rod-cone interactions in mesopic vision -- 13.1 Rod-cone interactions under mesopic conditions in a chromatically neutral state of adaptation -- 13.2 Rod-cone interactions under mesopic conditions in a chromatic state of adaptation -- 14 Further exploration of chromatic rod vision.

14.1 Contribution of J..J. McCann and J..L. Benton -- 14.2 Contribution of P..W. Trezona -- 14.3 Contribution of C..F. Stromeyer III -- 14.4 Contribution of S. Buck and co-workers -- 14.5. Contribution of J..L. Nerger and co-workers -- Part IV Theories of sensitivity regulation of the rod and cone systems: a historical account -- 15 Introduction -- 16 Early photochemical explanations -- 17 Contribution of S. Hecht -- 17.1 Hecht's photochemical theory -- 17.2 Supporting evidence obtained from invertebrates -- 17.3 Supporting evidence obtained from psychophysical experiments -- 18 Contribution of G. Wald: photochemical sensitivity regulation mechanisms of rods and cones -- 18.1 Molecular basis of bleaching and regeneration of photopigments in rods and cones -- 18.2 Serious challenges to the photochemical theory -- 18.3 The neural factor refuted -- 19 Relationship between amount of rhodopsin and sensitivity during dark adaptation -- 19.1 Results of Tansley -- 19.2 Results of Granit -- 19.3 Granit' s explanation -- 19.4 Wald' s explanation: compartment theory -- 19.5 A logarithmic relationship between sensitivity and amount of bleached photopigment -- 19.6 Contribution of J.E. Dowling -- 19.7 Contribution of W.A.H. Rushton: relationship between sensitivity and amount of bleached rhodopsin in humans -- 20 Post-receptor sensitivity regulation mechanisms -- 20.1 Psychophysical evidence -- 20.2 Anatomical and electrophysiological evidence -- 21 Rushton' s AGC model -- 21.1 Each receptor type has a separate and independent adaptation pool -- 21.2 Are light and dark adaptation really equivalent? -- 21.3 A decisive experiment -- 21.4 The adaptation mechanisms explored by the after-flash technique -- 21.5 Limitations of Rushton' s photochemical theory -- 22 Contribution of H..B. Barlow -- 22.1 Dark and Light adaptation based on similar mechanisms.

22.2 Both noise and neural mechanisms involved -- 22.3 Evidence in support of the noise theory -- 22.4 Opposing evidence -- 22.5 Sensitivity difference between rods and cones explained -- 23 Rushton and Barlow compared -- 24 The Dowling-Rushton equation refuted -- 24.1 Contribution of T.D. Lamb -- 24.2 The search for a new formula -- 24.3 Differences between rod and cone dark adaptation -- 24.4 Light and dark adaptation are not equivalent -- 24.5 Allosteric regulation of dark adaptation -- 24.6 A search for the allosteric adaptation mechanisms -- 25 Several mechanisms involved in sensitivity regulation -- 26 Sensitivity regulation due to rod-cone interaction -- 27 Modern conceptions of sensitivity regulation -- Part V Factors that triggered the paradigm shifts in the development of the duplicity theory -- 28 Summary of K..R. Poppers and T..S. Kuhns models of scientific development -- 29 The development of the duplicity theory as a test of Poppers and Kuhns models -- References -- Index.