Although the study of visual perception has made more progress in the past 40 years than any other area of cognitive science, there remain major disagreements as to how closely vision is tied to general cognition. This paper sets out some of the arguments for both sides and defends the position that an important part of visual perception, which may be called early vision or just vision, is prohibited from accessing relevant expectations, knowledge and utilities - in other words it (...) is cognitively impenetrable. That part of vision is complex and articulated and provides a representation of the 3-D surfaces of objects sufficient to serve as an index into memory, with somewhat different outputs being made available to other systems such as those dealing with motor control. The paper also addresses certain conceptual and methodological issues, including the use of signal detection theory and event-related potentials to assess cognitive penetration of vision. A distinction is made among several stages in visual processing. These include, in addition to the inflexible early-vision stage, a pre-perceptual attention allocation stage and a post-perceptual evaluation, memory-accessing, and inference stage which provide several different highly constrained ways in which cognition can affect the outcome of visual perception. The paper discusses arguments that have been presented in both computer vision and psychology showing that vision is "intelligent" and involves elements of problem solving". It is suggested that these cases do not show cognitive penetration, but rather they show that certain natural constraints on interpretation, concerned primarily with optical and geometrical properties of the world, have been compiled into the visual system. The paper also examines a number of examples where instructions and "hints" are alleged to affect. (shrink)

Most people, including philosophers, tend to classify human motives as falling into one of two categories: the egoistic or the altruistic, the self-interested or the moral. According to Susan Wolf, however, much of what motivates us does not comfortably fit into this scheme. Often we act neither for our own sake nor out of duty or an impersonal concern for the world. Rather, we act out of love for objects that we rightly perceive as worthy of love--and it is these (...) actions that give meaning to our lives. Wolf makes a compelling case that, along with happiness and morality, this kind of meaningfulness constitutes a distinctive dimension of a good life. Written in a lively and engaging style, and full of provocative examples, Meaning in Life and Why It Matters is a profound and original reflection on a subject of permanent human concern. (shrink)