He warns against doing that in his concluding remarks (Dodwell 20-22) by saying that any attempts at over-simplification of the problem will not solve it. Understanding perceptions, he maintains, is a great challenge (Dodwell 22). He attempts, therefore, to give a general overview of the different subjects, ranging from the study of visual illusions to understanding binocular vision and depth perception that can aid us in understanding the complexity of the visual system. He, too, has used various illustrations to clarify his arguments. The success and effectiveness, relative and absolute, of the illustrations used by these authors will now be discussed in detail. .
Gregory, throughout his book, has used numerous illustrations to accompany the text. He has also taken the aid of various plates, added at the end of the book, to qualify his claims. At most occasions, the illustrations used by him are accompanied by comprehensive prose explaining them. Generally, The images and the prose have reinforced each other to add to the palatability of Gregory's argument. Figure 10.11 (210) and plate 3, at the end of the book, aid in the explanation of his "hollow face" example of ambiguities of illusions (207-8). The diagram about constancy scaling, figure 10.18 (Gregory 223), along with the explanation on page 222, does a good job at explaining constancy scaling. His explanation of "paradox illusions" (235-8) is wonderfully aided by the three figures, 10.27-9 (238-40), of the impossible object and gets Gregory's point across remarkably well. At some occasions, the smart comparison of illustrations with each other has conveyed the argument very well. This can be seen in the account of Ponzo and Muller-Lyer illusions (218-22), figures 10.15-7, where Gregory explains the perspective theories regarding distortion illusions. .
One illustration that Gregory has used to particularly good effect is his speculative diagram of the mind-design for vision (251).
