From inference to affordance : the problem of visual depth-perception in the optical writings of Descartes, Berkeley, and Gibson

This thesis explores the debate and issues regarding the status of visual ;,iferellces in the optical writings of Rene Descartes, George Berkeley and James 1. Gibson. It gathers arguments from across their works and synthesizes an account of visual depthperception that accurately reflects the larger, metaphysical implications of their philosophical theories. Chapters 1 and 2 address the Cartesian and Berkelean theories of depth-perception, respectively. For Descartes and Berkeley the debate can be put in the following way: How is it possible that we experience objects as appearing outside of us, at various distances, if objects appear inside of us, in the representations of the individual's mind? Thus, the Descartes-Berkeley component of the debate takes place exclusively within a representationalist setting. Representational theories of depthperception are rooted in the scientific discovery that objects project a merely twodimensional patchwork of forms on the retina. I call this the "flat image" problem. This poses the problem of depth in terms of a difference between two- and three-dimensional orders (i.e., a gap to be bridged by one inferential procedure or another). Chapter 3 addresses Gibson's ecological response to the debate. Gibson argues that the perceiver cannot be flattened out into a passive, two-dimensional sensory surface. Perception is possible precisely because the body and the environment already have depth. Accordingly, the problem cannot be reduced to a gap between two- and threedimensional givens, a gap crossed with a projective geometry. The crucial difference is not one of a dimensional degree. Chapter 3 explores this theme and attempts to excavate the empirical and philosophical suppositions that lead Descartes and Berkeley to their respective theories of indirect perception. Gibson argues that the notion of visual inference, which is necessary to substantiate representational theories of indirect perception, is highly problematic. To elucidate this point, the thesis steps into the representationalist tradition, in order to show that problems that arise within it demand a tum toward Gibson's information-based doctrine of ecological specificity (which is to say, the theory of direct perception). Chapter 3 concludes with a careful examination of Gibsonian affordallces as the sole objects of direct perceptual experience. The final section provides an account of affordances that locates the moving, perceiving body at the heart of the experience of depth; an experience which emerges in the dynamical structures that cross the body and the world.

Inspiration and mimesis in Plato's criticism of poetry

Plato criticizes poetry in several of his dialogues, beginning with Apology, his first work, and ending with Laws, his last. In these dialogues, his criticism of poetry can be divided into two streams: poetry is criticized for either being divinely inspired, or because it is mimetic or imitative of reality. However, of the dialogues which criticize poetry in these ways, it is not until Laws that Plato mentions both inspiration and mimesis together, and then it is only in a few sentences. Furthermore, nowhere in the dialogues does Plato discuss their relationship. This situation has a parallel in the secondary literature. While much work has been done on inspiration or mimesis in Plato’s criticism of poetry, very little work exists which discusses the connection between them. This study examines Plato’s treatment - in the six relevant dialogues - of these two poetic elements, inspiration and mimesis, and shows that a relationship exists between them. Both can be seen to relate to two important Socratic-Platonic concerns: the care of the soul and the welfare of the state. These concerns represent a synthesis of Socratic moral philosophy with Platonic political beliefs. In the ‘inspiration’ dialogues, Ion, Apology, Meno, Phaedrus and Laws, poetic inspiration can affect the Socratic exhortation which considers the care of the individual soul. Further, as we are told in Apology, Crito and Gorgias, it is the good man, the virtuous man - the one who cares for his soul - who also cares for the welfare of the state. Therefore, in its effect on the individual soul, poetic inspiration can also indirectly affect the state. In the ‘mimesis’ dialogues, Republic and Laws, this same exhortation, on the care of the soul, is posed, but it is has now been rendered into a more Platonic form - as either the principle of specialization - the ‘one man, one job’ creed of Republic, which advances the harmony between the three elements of the soul, or as the concord between reason and emotion in Laws. While in Republic, mimesis can damage the tripartite soul's delicate balance, in Laws, mimesis in poetry is used to promote the concord. Further, in both these dialogues, poetic mimesis can affect the welfare of the state. In Republic, Socrates notes that states arc but a product of the individuals of which they are composed Therefore, by affecting the harmony of the individual soul, mimesis can then undermine the harmony of the state, and an imperfect political system, such as a timarchy, an oligarchy, a democracy, or a tyranny, can result. However, in Laws, when it is harnessed by the philosophical lawgivers, mimesis can assist in the concord between the rulers and the ruled, thus serving the welfare of the state. Inspiration and mimesis can thus be seen to be related in their effect on the education of both the individual, in the care of the soul, and the state, in its welfare. Plato's criticism of poetry, therefore, which is centred on these two features, addresses common Platonic concerns: in education, politics, ethics, epistemology and psychology.

O legado de Descartes

The criticism of Cartesian philosophy is correlated on four pillars: the fragmentation of knowledge, the separation between mind and body, the impossibility of the reductionist method for explanation of natural phenomena, and in the superiority of the reason as the only valid form of knowledge. These last two pillars, as many environmentalists claim, contributed decisively to the devaluation of the res extensa over the res cogitans. To check this we used as a theoretical framework the following texts: Discourse on Method, Rules for Conduct of the Spirit and Metaphysical Meditations. By reading these works it was found that the first two pillars (the fragmentation of knowledge and the separation between mind and body) there are no theoretical basis in texts. The failure of the reductionist method to explain the ecological and atomic phenomena and the overcoming of reason as the only valid form of knowledge are supported in their philosophy.

The biomechanics of the hip joint using new diagnostic aspects in the field of hip joint dysplasia. Constructive criticism of hip dysplasia diagnosis and present marketable breeding methods with an outlook on future perspectives and possibilities. Part I

In absence of basic canine hip biomechanics, a specific, consequent three dimensional concept to evaluate the coxofemoral joint was developed for the dog. With the help of a new method to radiologically demonstrate the hip in a physiological standing position several new clinically relevant aspects could be further investigated. For example the breed specific anatomical differences in the hip, and dynamics and the background on "iatrogenic luxations" in HD diagnostics could be shown. The caudal luxation and the growth abnormalities of the hip and their consequences on the whole leg (antetorsion syndrome) as a consequence of inadequate breeding could be demonstrated.

Web Classroom Application. Digital technologies to study theory, history and criticism of architecture at Escuela Superior de Arquitectura UPMadrid. The search for some guides to direct the inquiry learning

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