UMD Theses and Dissertations
Permanent URI for this collectionhttp://hdl.handle.net/1903/3
New submissions to the thesis/dissertation collections are added automatically as they are received from the Graduate School. Currently, the Graduate School deposits all theses and dissertations from a given semester after the official graduation date. This means that there may be up to a 4 month delay in the appearance of a given thesis/dissertation in DRUM.
More information is available at Theses and Dissertations at University of Maryland Libraries.
Browse
3 results
Search Results
Item Structuralism and Natural Philosophy: Method, Metaphysics and Explanation(2009) Cifone, Michael Christian; Bub, Jeffrey; Philosophy; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)This dissertation is an examination of the foundations of what I call a "fourth" tradition of analytical-scientific philosophy, the tradition of "structuralism". It is a disavowal of a metaphysics of substances and/or entities in the pursuit of scientific theory and truth. We look, in particular, at the current manifestation of this tradition, which advances the thesis of "structural realism"; we ask how tenable this thesis is, and whether we can weaken it. I argue that we should focus on methodology--a program for the formulation of scientific hypotheses about the sorts of things there are--rather than on metaphysics per se. We replace "substance" with "relation" as the basic ontic posit, and hold that substances or entities are metaphysically derivative from relational structure. Thus, the thesis is not that "there are no things" (or that "everything must go", as Ladyman et al. suppose); rather, the thesis is that the things (entities or substances) are relational structure, and there is no complete specification of an independent entity that is not itself more relational structure (so a metaphysics of substances is merely secondary to that of relational structure). I also suggest that there is no complete, unitary or monistic theory of what `structure' itself is. That is, I hold that there is no "total" structure of which everything that is relational structure is a "part", on the grounds that this would constitute an "illegitimate totality" in Russell's sense (the claim that "everything is structural" does not mean that there is a single structure which everything has--what a monistic theory of structure seems to demand). We then turn to the question of scientific explanation in light of structural realism: can there be explanation without a metaphysics of substances? I answer affirmatively. I then turn to two cases where, I argue, structuralism (and the specific thesis of structural realism) is in play regarding scientific explanation: quantum information theory, and the recent attempt to render quantum mechanics local by re-interpreting physical law time symmetrically. I conclude with a consideration of some objections to structuralism, and an articulation of the general view of metaphysics that structuralism seems to presuppose.Item Quantum Mechanics and Quantum Information Theory(2009) Van Camp, Wesley W.; Bub, Jeffrey; Philosophy; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)The principle aim of this dissertation is to investigate the philosophical application of quantum information theory to interpretational issues regarding the theory of quantum mechanics. Recently, quantum information theory has emerged as a potential source for such an interpretation. The main question with which this dissertation will be concerned is whether or not an information-theoretic interpretation can serve as a conceptually acceptable interpretation of quantum mechanics. It will be argued that some of the more obvious approaches - that quantum information theory shows us that ultimately the world is made of information, and quantum Bayesianism - fail as philosophical interpretations of quantum mechanics. However, the information-theoretic approach of Clifton, Bub, and Halvorson introduces Einstein's distinction between principle theories and constructive theories, arguing that quantum mechanics is best understood as an information-theoretic principle theory. While I argue that this particular approach fails, it does offer a viable new philosophical role for information theory. Specifically, an investigation of interpretationally successful principle theories such as Newtonian mechanics, special relativity, and general relativity, shows that the particular principles employed are necessary as constitutive elements of a framework which partially defines the basic explanatory concepts of space, time, and motion. Without such constitutive principles as preconditions for empirical meaning, scientific progress is hampered. It is argued that the philosophical issues in quantum mechanics stem from an analogous conceptual crisis. On the basis of this comparison, the best strategy for resolving these problems is to apply a similar sort of conceptual analysis to quantum mechanics so as to provide an appropriate set of constitutive principles clarifying the conceptual issues at stake. It is further argued that quantum information theory is ideally placed as a novel conceptual framework from which to conduct this analysis.Item Debugging and Repair of OWL Ontologies(2006-07-26) Kalyanpur, Aditya Anand; Hendler, James; Computer Science; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)With the advent of Semantic Web languages such as OWL (Web Ontology Language), the expressive Description Logic SHOIN is exposed to a wider audience of ontology users and developers. As an increasingly large number of OWL ontologies become available on the Semantic Web and the descriptions in the ontologies become more complicated, finding the cause of errors becomes an extremely hard task even for experts. The problem is worse for newcomers to OWL who have little or no experience with DL-based knowledge representation. Existing ontology development environments, in conjunction with a reasoner, provide some limited debugging support, however this is restricted to merely reporting errors in the ontology, whereas bug diagnosis and resolution is usually left to the user. In this thesis, I present a complete end-to-end framework for explaining, pinpointing and repairing semantic defects in OWL-DL ontologies (or in other words, a SHOIN knowledge base). Semantic defects are logical contradictions that manifest as either inconsistent ontologies or unsatisfiable concepts. Where possible, I show extensions to handle related defects such as unsatisfiable roles, unintended entailments and non-entailments, or defects in OWL ontologies that fall outside the DL scope (OWL-Full). The main contributions of the thesis include: * Definition of three novel OWL-DL debugging/repair services: Axiom Pinpointing, Root Error Pinpointing and Ontology Repair. This includes formalizing the notion of precise justifications for arbitrary OWL entailments (used to identify the cause of the error), root/derived unsatisfiable concepts (used to prune the error space) and semantic/syntactic relevance of axioms (used to rank erroneous axioms). * Design and Analysis of decision procedures (both glass-box or reasoner dependent, and black-box or reasoner independent) for implementing the services * Performance and Usability evaluation of the services on realistic OWL-DL ontologies, which demonstrate it's practical use and significance for OWL ontology modelers and users