The much larger appearance of the moon near horizon than the perceived size of the moon at zenith has motivated many scientists to develop theories that aim at explaining this puzzling phenomenon. Considering that the size of retinal images of the moon in these positions are very similar, the explanation of difference in their apparent sizes has relied on perceptual cues of distance embedded in the retinal image of their respective contexts. Although this account of the moon illusion is quite (...) popular, it does not explain all aspects of this phenomenon. The theoretical formulation of the moon illusion based on other factors such as size contrast later may have had some advantages but has also created some new problems. Although the moon is perceived in a three-dimensional (3D) environment, the present analysis proposes that an explanation of the moon illusion based on two-dimensional (2D) cues can remove some of the unnecessary problems. The empty space and size contrast that have already been considered in explaining classic geometric-optical illusions play a parallel role in explaining the moon illusion. In other words, the role of open space in interaction with the image of the moon and different objects near horizon, all reflected on the retina, are considered as the main explaining factors. The advantages of this approach will be discussed and some of the facts pertaining to the moon illusion will be explained within this theoretical framework. (shrink)

George Berkeley argues that vision is a language of God, that the immediate objects of vision are arbitrary signs for tactile objects and that there is no necessary connection between what we see and what we touch. Thomas Reid, on the other hand, aims to establish a geometrical connection between visible and tactile figures. Consequently, although Reid and Berkeley's theories of vision share important elements, Reid explicitly rejects Berkeley's idea that visible figures are merely arbitrary signs for tangible bodies. But (...) is he right in doing so? I show that many passages in Berkeley's work on vision suggest that he acknowledges a geometrical connection between visibles and tangibles. So the opposition between the arbitrariness Berkeley defends and a geometrical connection cannot be as universal as Reid thinks. This paper seeks to offer a plausible reading of Berkeley's theory of vision in this regard and an explanation of why Reid interprets Berkeley differently. (shrink)

Berkeley desarrolla su teoría de la visión en la obra de juventud Ensayo para una nueva teoría de la visión, que por lo general ha sido leída atendiendo sólo a sus aspectos científicos o perceptuales. En este artículo propongo una lectura distinta, que busca mostrar que el Ensayo no sólo atiende aspectos científicos sino, por el contrario, anticipa el inmaterialismo de obras posteriores. Esto lo hace porque Dios cumple un importante papel en él, lo cual se debe, entre otras cosas, (...) a que la teoría de la visión es desarrollada en función de Dios, pues de Él depende tanto la vista y los objetos visibles como el argumento del lenguaje visual. (shrink)

Ever since Berkeley discussed the problem at length in his Essay Toward a New Theory of Vision, theorists of vision have attempted to explain why the moon appears larger on the horizon than it does at the zenith. Prevailing opinion has it that the contemporary perceptual psychologists Kaufman and Rock have finally explained the illusion. This paper argues that Kaufman and Rock have not refuted a Berkeleyan account of the illusion, and have over-interpreted their own experimental results. The moon illusion (...) remains unexplained, and a Berkeleyan account is still a contender. (shrink)

There are two related points at which J.J. Gibson’s ecological theory of visual perception remains remarkably underspecified: Firstly, the notion of information for perception is not explicated in much detail beyond the claim that it “specifies” the environment for perception, and, thus being an objective affair, enables an organism to perceive action possibilities or “affordances.” Secondly, misperceptions of affordances and perceptual illusions are not clearly distinguished from each other. Although the first claim seems to suggest that any perceptual illusion amounts (...) to the misperception of affordances, there might be some relevant differences between various ways of getting things wrong. In this essay, Gibson’s notion of “specifying” information shall be reconstructed along the lines of Fred Dretske’s relational theory of information. This refined notion of information for perception will then be used to carve out the distinction between perceptual illusions and the misperception of affordances, with some help from the “Empirical Strategy” (developed by Purves et al.). It will be maintained that there are cases where perceptual illusions actually help an organism to correctly perceive an affordance. In such cases, the prima facie misrendered informational relations involved are kept intact by a set of appropriate transformation rules. Two of Gibson’s intuitions shall thus be preserved: the objectivity of informational relations and the empowerment of the organism as an active perceiver who uses those objective relations to his specific ends. (shrink)

Ein Homunkulus im philosophischen Sprachgebrauch ist eine postulierte menschenähnliche Instanz, die ausdrücklich oder unausdrücklich zur Erklärung der Arbeitsweise des menschlichen Geistes herangezogen wird. Als Homunkulus-Fehlschluß wird die Praxis bezeichnet, Prädikate, die auf kognitive oder perzeptive Leistungen einer ganzen Person zutreffen, auch auf Teile von Personen oder auf subpersonale Vorgänge anzuwenden, was typischerweise zu einem Regreß führt. Der vorliegende Beitrag erörtert den Homunkulus-Fehlschluß zunächst in argumentationstheoretischer Hinsicht und stellt dabei ein Diagnoseschema auf. Dann werden zwei Anwendungsfelder erörtert: Instanzenmodelle der Psyche (Platon, (...) Freud) sind ihrer Natur nach homunkulusgefährdet, denn es ist aufgrund der holistischen Zuschreibungsbedingungen mentaler Fähigkeiten schwer plausibel zu machen, wie eine innerpsychische Instanz den ihr zugedachten Beitrag leisten soll, ohne über eine eigene Psyche zu verfügen. Der zweite Anwendungsfall ist das Problem des invertierten Netzhautbildes in der Philosophie der Wahrnehmung, das wissenschafts- und philosophiegeschichtlich eingebettet und unter besonderer Berücksichtigung von Descartes diskutiert wird. Schließlich werden offensive Rechtfertigungen homunkularer Redeweisen erörtert und größtenteils zurückgewiesen. (shrink)