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.

The landscape of work engagement in brain injury rehabilitation /

This study examined work engagement among brain injury rehabilitation professionals with specific attention to how they engage with their work (the extent to which they experience vigor, dedication, and absorption while working) and how they engage with people (the degree to which they are welcoming towards others and demonstrate integrity, responsibility, transparency). This study also tested a theoretical model of work engagement that predicted a relationship between engagement and personal, interpersonal, and organizational capacity. Eighty-one staff employed in a hospital-based brain injury program participated in the study. A quantitative self-report survey was used to measure participants' levels of capacity and engagement and a qualitative question was included to identify initiatives that could be introduced to enhance job performance. As predicted by the model, there were statistically significant positive correlations among all three capacity variables and engagement with work and statistically significant positive correlations between ethical engagement and personal and interpersonal capacity. The results of the qualitative data analysis revealed three broad categories of recommendations for improving job performance (more learning opportunities, more resources to support professional development, and the need to build greater team cohesion). These findings provide initial support for a theoretical model that emphasizes the link between capacity and engagement, which could be used to guide theory-driven interventions aimed at improving the work environment.

Assessing evaluative measures for Internet-based courseware

Although there is a consensus in th~ literature on the many uses of the Internet in education, as well as the unique features of the Internet for presenting facts and information, there is no consensus on a standardized method for evaluating Internetbased courseware. Educators rarely have the opportunity to participate in the development of Internet-based courseware, yet they are encouraged to use the technology in their learning environments. This creates a need for summative evaluation methods for Internet-based health courseware. The purpose ofthis study was to assess evaluative measures for Internet-based courseware. Specifically, two entities were evaluated within the study: a) the outcome of the Internet-based courseware, and b) the Internet-based courseware itself. To this end, the Web site www.bodymatters.com was evaluated using two different approaches by two different cohorts. The first approach was a performance appraisal by a group of endusers. A positive, statistically significant change in the students performance was observed due to the intervention ofthe Web site. The second approach was a productoriented evaluation ofthe Web site with the use of a criterion-based checklist and an open-ended comments section. The findings indicate that a summative, criterion-based evaluation is best completed by a multidisciplinary team. The findi~gs also indicated that the two different cohorts reported different product-oriented appraisals of the Web site. The current research confirmed previous research that found that experts returning a poor evaluation of a Web site did not have a relationship to whether or not the end-users performance improved due to the intervention of the Web site.

An appeal to the people ; being a review of the late correspondence and documents, relating to the rejection of the British Minister : including an examination of the "arrangement" of April last /

Introduction "To the people of the United States" signed Wm. Coleman.

The Princeps Optimus : towards a new reading of Velleius Paterculus' history

Abstract This thesis works towards a new reading ofVelleius Paterculus' survey of Roman history, published in AD 29 or 30. Modem scholarship has tended to condemn Velleius as historian and stylist. Though opinions have started to change in the last few decades, even the most recent works generally treat him as a passive and perhaps unconscious conveyor of Roman cultural ideals and Augustan ideology. This thesis argues that the historian is, in fact, manipulating these themes to make definite political points. It focuses on the negativity of the history's conclusion as it stands in stark contrast to the preceding narrative celebrating the principates of Augustus and Tiberius. The thesis tentatively concludes that Velleius was trying to express concern over Rome's future, and specifically to influence Tiberius to return to Rome from his retreat on the island of Capri and curb the power of his "assistant," Sejanus.

Remarks and criticism on the Hon. John Quincy Adams's letter to the Hon. Harrison Gray Otis

Printed by Joshua Cushing