Debunking arguments typically attempt to show that a set of beliefs or other intensional mental states bear no appropriate explanatory connection to the facts they purport to be about. That is, a debunking argument will attempt to show that beliefs about p are not held because of the facts about p. Such beliefs, if true, would then only be accidentally so. Thus, their causal origins constitute an undermining defeater. Debunking arguments arise in various philosophical domains, targeting beliefs about morality, the (...) existence of God, logic, and others. They have also arisen in material-object metaphysics, often aimed at debunking common-sense ontology. And while most of these arguments feature appeals to ‘biological and cultural contingencies’ that are ostensibly responsible for our beliefs about which kinds of objects exist, few of them take a serious look at what those contingencies might actually be. The purpose of this paper is twofold. First, to remedy this by providing empirical substantiation for a key premise in these debunking arguments by examining data from cognitive science, evolutionary biology, and developmental psychology that support a ‘debunking explanation’ of our common-sense beliefs and intuitions about which objects exist. Second, to argue that such data also undermines a particular kind of rationalist defense of common-sense ontology, sometimes employed as a response to the debunking threat. (shrink)

Adults and infants display a robust ability to perceive the unity of a center-occluded object when the visible ends of the object undergo common motion (e.g. Kellman, P.J., Spelke, E.S., 1983. Perception of partly occluded objects in infancy. Cognitive Psychology 15, 483±524). Ecologically oriented accounts of this ability focus on the primacy of motion in the perception of segregated objects, but Gestalt theory suggests a broader possibility: observers may perceive object unity by detecting patterns of synchronous change, of which common (...) motion is a special case. We investigated this possibility with observations of adults and 4-month-old infants. Participants viewed a center-occluded object whose visible surfaces were either misaligned or aligned, stationary or moving, and unchanging or synchronously changing in color or bright- ness in various temporal patterns (e.g. ¯ashing). Both alignment and common motion con- tributed to adults' perception of object unity, but synchronous color changes did not. For infants, motion was an important determinant of object unity, but other synchronous changes and edge alignment were not. When a stationary object with aligned edges underwent syn- chronous changes in color or brightness, infants showed high levels of attention to the object, but their perception of its unity appeared to be indeterminate. An inherent preference for fast over slow ¯ash rates, and a novelty preference elicited by a change in rate, both indicated that infants detected the synchronous changes, although they failed to use them as information for object unity. These ®ndings favor ecologically oriented accounts of object perception in which surface motion plays a privileged role. Ó 1999 Elsevier Science B.V. All rights reserved. (shrink)