The phenomenology of the invisible: From visual syntax to "shape from shapes"

Here, we address the phenomenology of visual objects, using verbal reports, spontaneous descriptions, answers to questions and responses to suggestions, as well as free associations. We occasionally ask for simple sketches. Such methods allow probing of the deep structure of visual awareness. This is above all revealed by what is not spontaneously mentioned, or is only mentioned by way of incidental properties. It is also disclosed by changes induced by minor variations or additions. We find remarkable agreement over a large number of participants. Thus verbal reports are a powerful probe of visual structure. Similarly to language, "simple visual objects" have deep roots in subsidiary awareness. These "invisible" foundations serve to define simple figures, like a "square", as unique, prototypical objects. The nature of "visual objects" thus involves an extensive "invisible" realm. Without taking this into account, a proper understanding of the nature of the visual object is not possible. Finally, this should lead to a formal syntactical theory of basic visual shapes.