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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
21

Reliability and Validity of Experiment in the Neurobiology of Learning and Memory

Sullivan, Jacqueline A. 27 September 2007 (has links)
The concept of reliability has been defined traditionally by philosophers of science as a feature that an experiment has when it can be used to arrive at true descriptive or explanatory claims about phenomena. In contrast, philosophers of science typically take the concept of validity to correspond roughly to that of generalizability, which is defined as a feature that a descriptive or explanatory claim has when it is based on laboratory data but is applicable to phenomena beyond those effectsunder study in the laboratory. Philosophical accounts of experiment typically treat of the reliability of scientific experiment and the validity of descriptive or explanatory claims independently. On my account of experiment, however, these two issues are intimately linked. I show by appeal to case studies from the contemporary neurobiology of learning and memory that measures taken to guarantee the reliability of experiment often result in a decrease in the validity of those scientific claims that are made on the basis of such experiments and, furthermore, that strategies employed to increase validity often decrease reliability. Yet, since reliability and validity are both desirable goals of scientific experiments, and, on my account, competing aims, a tension ensues. I focus on two types of neurobiological experiments as case studies to illustrate this tension: (1) organism-level learning experiments and (2) synaptic-level plasticity experiments. I argue that the express commitment to the reliability of experimental processes in neurobiology has resulted in the invalidity of mechanistic claims about learning and plasticity made on the basis of data obtained from such experiments. The positive component of the dissertation consists in specific proposals that I offer as guidelines for resolving this tension in the context of experimental design.
22

The Unity of Science in Early-Modern Philosophy: Subalternation, Metaphysics and the Geometrical Manner in Scholasticism, Galileo and Descartes

Biener, Zvi 10 June 2008 (has links)
The project of constructing a complete system of knowledge---a system capable of integrating all that is and could possibly be known---was common to many early-modern philosophers and was championed with particular alacrity by René Descartes. The inspiration for this project often came from mathematics in general and from geometry in particular: Just as propositions were ordered in a geometrical demonstration, the argument went, so should propositions be ordered in an overall system of knowledge. Science, it was thought, had to proceed `more geometrico'. I offer a new interpretation of `science emph{more geometrico}' based on an analysis of the explanatory forms used in certain branches of geometry. These branches were optics, astronomy, and mechanics; the so-called subalternate, subordinate, or mixed-mathematical sciences. In Part I, I investigate the nature of the mixed-mathematical sciences according to Aristotle and some `liberal Jesuit' scholastic-Aristotelians. In Part II, the heart of the work, I analyze the metaphysics and physics of Descartes' "Principles of Philosophy" (1644, 1647) in light of the findings of Part I and an example from Galileo. I conclude by arguing that we must broaden our understanding of the early-modern conception of `science more geometrico' to include concepts taken from the mixed-mathematical sciences. These render the geometrical manner more flexible than previously thought.
23

God's Dice: A Dramatic Exploration of Quantum Metaphysics

Tamler, Cory 30 April 2009 (has links)
I have already written one play, Not Eureka, which explores one way in which theatre can give a voice to science. While not a traditional science history play, Not Eureka concerns, and I hope illuminates, several scientific experiments of historical significance. In my current research, I have continued to explore ways to incorporate science into theatre. My project is similar to Not Eureka in that I am engaged in writing a new, full-length play (City Lights, Receding), based on research and scientific in focus. However, the project is not a repeat of my previous work. Instead of recounting and clarifying already fairly well-established scientific concepts, City Lights, Receding is philosophical, speculative, in nature. My focus as a History and Philosophy of Science (HPS) major is in the philosophy of quantum physics. I find this particular area of physical-philosophical inquiry both appealing and dramatic. My play explores, in a dramatic, speculative way, the philosophical problems presented by modern physics, and the conflict between the classical and modern worlds. I completed a graduate seminar in the philosophy of quantum mechanics in fall 2007. Since then, I have pursued research independently into the philosophy of quantum mechanics, identifying specific areas within the topic useful to the development of my script. I have focused on theories of interpretation such as GRW, many-worlds and many-minds theories. I have also been reading as many science-based plays as I can get my hands on. Fall 2008 began my writing period. By the beginning of spring semester 2009, I had a draft in reading-ready form; a seated reading through the Theatre Arts department, directed by Regina Connolly and featuring Charlie Brown (Verdenmacher), Parag S. Gohel (Armin), Mary Heyne (Marian), Lily Junker (Brody), and Joe McGranaghan (Albert Albert), was performed from April 9-11, 2009. Based on the reading and the response of audience and theatre/HPS faculty to it, I plan to revise the script with the goal of eventually pursuing full production opportunities.
24

Darwinism and Lamarckism before and after Weismann: A Historical, Philosophical, and Methodological Analysis.

Cartieri, Francis J 19 May 2009 (has links)
When exploring the relationship between two reputedly competitive scientific concepts that have persisted, with modification, through time, there are three main features to consider. First, there are historical features of an evolving relationship. Just as a causal story can be reconstructed concerning adaptations in a complex system, an analogous story can be supplied for the historical contingencies that have shaped the organization and development of Lamarckian and Darwinian biological thought, and their interactions, over time. Second, there are philosophical and conceptual features to the relationship-- what is shared, what is not, whether two ideas inherently conflict or conditionally conflict, etc. Third, there are methodological features to the relationshiphow do the theoretical concepts interact when in realistic operation? What are the benefits and constraints regarding their co-application? This project will explore the historical, philosophical, and methodological characteristics of the infamous Darwinian-Lamarckian dichotomy as characterized through Lakatos Methodology for Scientific Research Programs, with the hypothesis that, once the respective evolutionary philosophies are generalized and the clutter of stigma removed, there is a large degree of compatibility to be found among them. The justification for this project derives from the recent resurgence of interest in Lamarckian phenomena and the stern, often vehement backlash that has greeted that interest. If biologists and philosophers both resist, or worse dismiss, Lamarckian suggestions on the grounds that they perceive them to undermine and conflict with Darwinian lines of thought, then that resistance may be unconstructive and misguided, should it be the case that, just as it was with Darwins original conception of evolution, a more flexible, pluralistic view is plausible.
25

Practices, Perception, and Normative States

Zahle, Julie 25 June 2009 (has links)
Theories of practice are widespread within the humanities and the social sciences. They reflect the view that the study of, and theorizing about, social practices hold the key to a proper understanding of social life or aspects thereof. An important subset of theories of practice is ability theories of practice. These theories focus on the manner in which individuals draw on their abilities, skills, know-how, or practical knowledge when participating in social practices. In this dissertation, I concentrate on ability theories of practice as advanced within the social sciences and the philosophy of the social sciences. Ability theorists within these two fields stress individuals ability to act appropriately in situations of social interaction. But how, more precisely, is this ability to be understood? The thesis I develop and defend provides a partial answer to this important question: In situations of social interaction, individuals ability to act appropriately sometimes depends on their exercise of the ability directly to perceive normative states specified as the appropriateness of actions. In the first part of the dissertation, I introduce and motivate this thesis. I provide an overview of ability theories of practice and, against that background, I present my thesis. Though generally unexplored, influential ability theorists have toyed with the thesis. Or, their theories invite an extension in this direction. For this reason, I argue, the thesis constitutes a natural way in which further to develop their approach. In the second part of the dissertation, I develop and defend my thesis. First, I present a plausible way in which to make ontological sense of the claim that normative states are sometimes directly perceptible. Next, I offer an account of perception and argue that, by its lights, individuals sometimes have the ability directly to perceive normative states. Finally, I briefly show that individuals ability to act appropriately sometimes depends on their exercise of this ability directly to perceive normative states. From both a practical and a theoretical perspective, the development and defense of this thesis constitutes a valuable elaboration of the basic approach associated with ability theories of practice.
26

A Causal Interpretation of Selection Theory

Gildenhuys, Peter Avery 30 September 2009 (has links)
The following dissertation is an inferentialist account of classical population genetics. I present the theory as a definite body of interconnected inferential rules for generating mathematical models of population dynamics. To state those rules, I use the notion of causation as a primitive. First, I put forward a rule stating the circumstances of application of the theory, one that uses causal language to pick out the types of entities over which the theory may be deployed. Next, I offer a rule for grouping such entities into populations based on their competitive causal relationships. Then I offer a general algorithm for generating classical population genetics models for such populations on the basis of what causal influences operate within them. Dynamical models in population genetics are designed to demystify natural phenomena, chiefly to show how adaptation, altruism, and genetic polymorphism can be explained in terms of natural rather than supernatural processes. In order for the theory to serve this purpose, it must be possible to understand, in a principled fashion, when and how to deploy the theory. By presenting the theory as a system of ordered inferential rules that takes causal information as its critical input and yields dynamical models as its outputs, I show explicitly how classical population genetics functions as a non-circular theoretical apparatus for generating explanations. The generalization of the theory achieved by presenting it using causal vocabulary shows how the scope of the theory of natural selection extends beyond its traditional domain of systems distinguished by genetic variations.
27

The Causal Structure of Conscious Agency

Andersen, Holly Kristine 26 January 2010 (has links)
This dissertation presents a new approach to modeling the causal structure of conscious agency, with a foundation in the metaphysics of causation and empirical tools for incorporating scientific results into an enriched causal model of agency. I use an interventionist causal analysis and experimental evidence from cognitive science to demonstrate that conscious awareness plays several significant causal roles in action. I then consider metaphysical challenges to this approach, and demonstrate that higher level causes such as awareness are legitimately causal. I expose the flawed understanding of causation required for inferring the causal inertness of awareness from experimental evidence. This leads to a differentiation between metaphysical causal questions, about the nature of causation itself, from empirical questions, which apply causal analysis to actual systems in the world. I challenge the practice of focusing on the awareness of agency in order to address the causal role of awareness in agency on the grounds that it inappropriately internalizes conscious agency. To demonstrate how we ought to incorporate scientific results into philosophical theories of agency, I offer an empirically enriched view of conscious agency. I rely on an interventionist approach to develop an evidentiary framework to ascertain the extent to which conscious awareness is a causal factor in action. Based on results from automatism research, I demonstrate at least three important ways in which awareness is a major causal contributor to human action: conscious intentions or goals; conscious perceptual information relevant to the goal; and conscious execution. I then address the problematic assumption that 'higher level' causes are derivative from lower level ones. I introduce the notion of counterfactual robustness to show how, for single tokens of causation, microphysical explanations are often explanatorily inferior to macrophysical ones, and distort the explanandum. I allay concerns about my variable choice by showing that we cannot, even in principle, replace higher level variables such as awareness with lower level variables such as neuronal processing. I introduce the notion of causal articulation in complex systems as the means by which higher level causes have lower level effects, while avoiding problems encountered by other theories of downward causation.
28

Seeing Sound: Hans Jenny and the Cymatic Atlas

Lewis, Stephen 13 May 2010 (has links)
I argue that cymatic imaging processes are methods of artifactual data production rather than data collection and that the production of sonorous figures can be shown to be scientifically valuable when compared to other artifactual data production methods used in the past, particularly Alphonse Bertillons use of anthropometrics to organize police catalogues in the 19th century. By artifactual, I mean that the data produced through a cymatic regime are the result of the imaging practice, and do not exist in the world before they are manufactured through a contrived process. Cymatics, a mediating imaging practice, permits an enhanced visual access to acoustical phenomena that are typically only experienced through our senses of hearing and touch. Furthermore, the production of cymatic images allows both hobbyists and scientists to create atlases, visual data repositories, of sound, wave displacements, and other modal phenomena. Without the artifactual visual data produced by a process like cymatics, it is impossible to create image-based atlases of invisible phenomena like sound that show more than idealized graphics of a particular wave. In order for scientific cymatic atlases to be created, the methods of production of a cymatic image, especially the frequency of the wave displacement and the media through which that wave displacement is being propagated, must be faithfully recorded and measured in order for viewers of the atlas to know what particular phenomenon they are observing.. Though cymatics has been studied in detail since the Enlightenment, Dr. Hans Jenny was the first person to accurately record this auxiliary data, which allowed him to create the first cymatic atlas that was useful to scientists.
29

Assessing the Use of Follow-up Skeletal Surveys in Children with Suspected Physical Abuse

Singh, Ranjodh 14 May 2010 (has links)
Background: A follow-up SS (FSS) can provide additional clinical data in a subset of children that undergo an initial skeletal survey (ISS) for the evaluation of physical abuse. Three studies suggested that 33-57% of FSS identify additional fractures, but the study populations were small and highly selective. Objective: To assess a consecutive study sample of children who underwent an ISS and FSS, to evaluate the results of the ISS and FSS, and to calculate the proportion in whom clinical diagnosis depended on the FSS results. Methods: This was a retrospective, descriptive study of children who had an ISS and FSS at Children's Hospital of Pittsburgh of UPMC from 4/1/02 to 3/31/09. Data were collected about demographics, reason for and results of ISS and FSS, the interval in days between ISS and FSS, and whether the FSS affected clinical diagnosis. Results: During the 7-yr study period, 1470 children underwent an ISS. Eleven percent (169/1470) of these children also underwent a FSS. These 169 children made up the subjects of the study. The FSS identified 39 fractures in 16% (27/169) of the study subjects. All 39 fractures were rib, metaphyseal or metacarpal. The identification of new fractures on FSS led a definite diagnosis of abuse in 7.6% (7/92) of the subjects who did not have a previous diagnosis. These 7 subjects were all less than a year of age. The ISS identified no fractures in 43% (3/7) of these subjects. A total of 29 fractures that were felt to be equivocal of ISS were confirmed as normal variants on FSS. Conclusions: This is the largest study to evaluate the use of FSS. The proportion of subjects with additional fractures identified on FSS was lower than in previous studies. The FSS made a definite diagnosis of abuse in ~8% of subjects. A large number of equivocal fractures on ISS were felt to be normal variants on FSS. Future studies will compare children who only receive an ISS with those who receive an ISS and FSS to identify characteristics that, when present in a child undergoing an ISS, also warrant a FSS.
30

PHENOMENAL CONSCIOUSNESS AS SCIENTIFIC PHENOMENON? A CRITICAL INVESTIGATION OF THE NEW SCIENCE OF CONSCIOUSNESS

Sytsma, Justin 01 October 2010 (has links)
Phenomenal consciousness poses something of a puzzle for philosophy of science. This puzzle arises from two facts: It is common for philosophers (and some scientists) to take its existence to be phenomenologically obvious and yet modern science arguably has little (if anything) to tell us about it. And, this is despite over 20 years of work targeting phenomenal consciousness in what I call the new science of consciousness. What is it about this supposedly evident phenomenon that has kept it beyond the reach of our scientific understanding? I argue that phenomenal consciousness has resisted scientific explanation because there is no such phenomenon: What is in fact phenomenologically obvious has not resisted scientific explanation, exposing phenomenal consciousness as an unneeded and unwarranted theoretical construct that is not supported by the scientific evidence. I show this through an investigation of the new science. I detail how these researchers understand phenomenal consciousness, tie this understanding to the recent philosophical debates, and critically assess the reasons given for believing that such a scientific phenomenon exists.

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