Abstract

The theory-ladenness of perception argument is not an argument at all. It is two clusters of arguments. The first cluster is empirical. These arguments typically begin with a discussion of one or more of the following psychological phenomena: (a) the conceptual penetrability of the visual system, (b) voluntary perceptual reversal of ambiguous figures, (c) adaptation to distorting lenses, or (d) expectation effects. From this evidence, proponents of theory-ladenness typically conclude that perception is in some sense "laden" with theory. The second cluster attempts to extract deep epistemological lessons from this putative fact. Some philosophers conclude that science is not (in any traditional sense) a rational activity, while others conclude that we must radically reconceptualize what scientific rationality involves. Once we understand the structure of these arguments, much conventional wisdom about the significance of the psychological data turns out to be false.