Consider for a moment the spatial and chromatic dimensions of your visual expe- rience. Suppose that as you gaze about the room you see a table, some books, and papers. Ignore for now the fact that you immediately recognize these objects to be a table with books and papers on it. Concentrate on how the table looks to you: its top spreads out in front of you, stopping at edges beyond which lies un?lled space, leading to more or less distant (...) chairs, shelves, or expanses of ?oor. The books and paper on the table top create shaped visual boundaries between areas of different color, within which there may be further variation of color or visual texture. Propelled by a slight breeze, a sheet of paper slides across the table, and you experience its smooth motion before it ?oats out of sight. (shrink)

How are we able to perceive the world veridically? If we ask this question as a part of the scientific investigation of perception, then we are not asking for a transcendental guarantee that our perceptions are by and large veridical; we presuppose that they are. Unless we assumed that we perceived the world for the most part veridically, we would not be in a position to investigate our perceptual abilities empirically. We are interested, then, not in how it is possible (...) in general for us to perceive the world veridically, but instead in what the relation is between our environment and its properties, of which we have knowledge, on the one hand, and our perceptual mechanisms, on the other, that results in very many, even most of our perceptions being veridical in everyday life. (shrink)

'Epistemological constructivism' holds that vision is mediated by background preconceptions and is theory-laden. Hence, two persons with differing theoretical commitments see the world differently and they could agree on what they see only if they both espoused the same conceptual framework. This, in its turn, undermines the possibility of theory testing and choice on a common theory-neutral empirical basis. In this paper, I claim that the cognitive sciences suggest that a part of vision may be only indirectly penetrated by cognition (...) in a way that does not threaten retrieval of information from a visual scene in a bottom-up way. That blocks the constructivist epistemological thesis. However, since spatial attention, which can be cognitively driven, seems to permeate all stages of visual processes, one is led to conclude that there is no part of vision immune to direct cognitive interference. Against this, I elaborate on the role of spatial attention and argue that it does influence vision in a top-down manner, but it does so only in an indirect way. I then argue that the existence of visual processes that are only indirectly penetrated by cognition undermines the epistemological conclusions of constructivism. (shrink)

v. 1. Classical roots and medieval discussions -- v. 2. Renaissance controversis, later scholasticism, and the elimination of the intelligible species in modern philosophy.