Visual modules can be viewed as expressions of a marked analytic attitude in the study of vision. In vision psychology, this attitude is accompanied by hypotheses that characterize how visual modules are thought to operate in perceptual processes. Our thesis here is that there are what we call “intrinsic reasons” for the presence of such hypotheses in a vision theory, that is, reasons of a deductive kind, which are imposed by the partiality of the basic terms in the definition of (...) a module, and by peculiar characteristics of those terms. Specifically, we discuss three hypotheses of functional attributes: successive stages in the action of modules, residual indeterminacy of their effects, and the role of prior constraints. For each of the three, we indicate its occurrence in perceptual psychology, explain corresponding intrinsic reasons, and illustrate such reasons with examples. (shrink)

(2013). On the meaning of statements in psychophysics characterizing conditional indeterminacy of percepts. Philosophical Psychology: Vol. 26, No. 2, pp. 234-262. doi: 10.1080/09515089.2012.663715.

Summary By introducing the concept of “invariants”, Koffka endowed perceptual psychology with a flexible theoretical tool, which is suitable for representing vision situations in which a definite part of the stimulus pattern is relevant but not sufficient to determine a corresponding part of the perceived scene. He characterised his “invariance principle” as a principle conclusively breaking free from the “old constancy hypothesis”, which rigidly surmised point-to-point relations between stimulus and perceptual properties. In this paper, we explain the basic terms and (...) assumptions implicit in Koffka’s concept, by representing them in a set-theoretic framework. Then, we highlight various aspects and implications of the concept in terms of answers to six separate questions: forms of invariants, heuristic paths to them, what is invariant in an invariant, roots of conditional indeterminacy, variability vs. indeterminacy, and overcoming of the indeterminacy. Lastly, we illustrate the lasting value and theoretical power of the concept, by showing that Koffka’s insights relating to it do occur in modern perceptual psychology and by highlighting its role in a model of perceptual transparency. (shrink)