This dissertation examines the potential relations between the objects and processes different sciences study. It examines the history, motivations, and analytical consequences of the thesis that individual sciences (such as physics, biology, and psychology) essentially pick out and describe different 'levels' of reality. It argues against the notion that there are different levels of reality that divide empirical domains of enquiry from one another. It proposes an alternate, more fluid, conception of scientific boundaries based upon patterns of causation and spatio-temporal contexts.

This work demonstrates that one can accept Heidegger's radically new conception of human subjectivity without being committed to the negative social ontology that is often deemed to be its direct consequence. Heidegger rejects traditional theories of intersubjectivity because they characterize the self as a type of isolated, independent substance that is required to 'bridge the gap' to reach or recognize others like itself. In contrast, Heidegger argues that the self is defined by a fundamental sociality expressed by its immersion in shared public roles and norms. In doing so, however, he opens himself up to a long-standing critique: namely, by simply stipulating subjectivity's sociality, Heidegger grants it the status of an a priori category which cannot accommodate immediate experiences of others in their concrete particularity; others are simply interchangeable tokens whose uniqueness is subsumed under the generality of the established category. By engaging in an analysis of the nature of the a priori in Heidegger's work, I demonstrate that this 'social category' is in fact a responsiveness to the other in her unique temporal particularity. On this basis, I am able to provide a Heidegger-inspired account of respect and the origins of normativity. My dissertation thus provides a significantly different approach to Heidegger interpretation, and compensates for shortcomings in contemporary theories of intersubjectivity.

This work provides a phenomenological account of the experience of illness and the manner in which meaning is constituted in the physician-patient relationship. Rather than representing a shared reality between physician and patient, illness represents two quite distinct realities--the meaning of one being significantly and qualitatively different from the meaning of the other. This difference in meaning has important implications for medical practice in terms of achieving successful communication between doctor and patient, alleviating the patient's suffering and devising maximally effective therapeutic interventions. In disclosing the manner in which the individual constitutes the meaning of his experience, the phenomenological analysis reveals that physician and patient constitute the meaning of illness from within the context of different "worlds'--each "world" providing its own horizon of meaning. The difference in perspectives between physician and patient reflects a distinction between meaning which is grounded in lived experience and meaning which is not so grounded (between the "natural attitude" and the "naturalistic attitude"). This distinction is evident in the manner in which both illness and body are experienced differently by physician and patient. In particular, the illness constituted by the patient is distinct from, and cannot be identified with, the disease state constituted by the physician. A phenomenological analysis of body reveals that illness is fundamentally experienced by the patient as a disruption of the "lived body" rather than as a dysfunction of the biological body. This disruption of "lived body" incorporates the disorder of body, self and world and may include the disturbance of lived spatiality and lived temporality. Illness may cause the patient to objectify his body as a malfunctioning physiological organism but this conception of the body-as-object by the patient is significantly different from the physician's constitution of the body-as-scientific-object. There are certain essential characteristics which pertain to the lived experience of illness regardless of its idiosyncratic manifestation as a particular disease state. In recognizing these essential characteristics and in explicitly attending to the patient's meanings, the physician can effectively minimize the difference in understanding between himself and his patient.

In the sixteenth and seventeenth century, empiricists such as Pierre Gassendi and John Locke accounted for the human capacity to know about the world by emphasizing sensory access to information. These philosophers entertained skepticist doubts concerning reasoned knowledge and concluded that sure knowledge of the world is won primarily by empirical or sense-based studies. These views on our general knowledge and certainty support a variety of claims concerning scientific knowledge in particular. On the basis of their constructive skepticist stances, these two empiricists support arguments for the reality of scientific objects and a strongly empiricist methodology of gathering and organizing scientific knowledge. The hallmarks of their empiricist philosophies of science are a background essentialism which motivates the search for underlying causes, a probabilism about theory confirmation, and a ranking of knowledge-types by degrees of certainty. The similarities of their views illuminate the influence of Gassendi's writings on Locke. Their differences show us their varying conceptions of knowledge with certainty and of knowledge about the world.

Secular bioethics has been involved in the resolution of moral controversies both in the clinic and in the discussion of public policy and there are three models used to justify moral judgments in bioethics. The first is the foundational model which seeks to build a theoretical account of the moral life. The foundational project must confront two difficulties. First, it must come to terms with the dilemma that there is no universal account of the nature of moral reason. Second, each foundational account requires some ranking of moral values if it is to make content-full judgments. Absent a universal moral narrative there is no canonical ranking of values. Two attempts to circumvent these foundational dilemmas have been prominent in bioethics. The first is the middle level principle approach. This model appeals to a set of principles to justify moral judgments. The model assumes that these principles are shared and that they can resolve moral dilemmas without requiring the resolution of the foundational questions. The model faces three difficulties. First there is no conclusive argument as to why this list of principles should be canonical. Second, it is not clear how the principles are related to one another. Third, the principles, without foundations, are ambiguous in their meaning. Another attempt to avoid foundational dilemmas is the hope of Jonsen and Toulmin to revive some model of casuistry. Jonsen and Toulmin select the model of Roman Catholic casuistry in the High Middle Ages. Yet they fail to take full account of the moral values and moral authority which governed this practice of casuistry. Both casuistry and principlism argue that we can reach agreement on moral controversies without appeal to foundations. In carefully examining what is agreed to one comes to see that the assertion of agreement is a sham. It becomes clear that secular discourse in bioethics must rely on a procedural morality which is empty of content. Content-full moral judgments can only be understood and accepted within particular moral communities.

An ontological investigation into the way of Being for someone in irreversible coma through Martin Heidegger's Dasein-analysis. Ambiguity in the designation 'human being' leads to the conceptual confusion one experiences when encountering someone in irreversible coma, because the designation of 'human being' indicates both 'Homo Sapien' and 'Homo Sapien plus Dasein'. However, considering what he requires for Dasein, Heidegger's Dasein-analysis supports a higher brain function definition of death. Thus on an Heideggerian interpretation, someone in irreversible coma has died as Dasein, remaining in the world as a 'living corpse'.

Informed consent is valid only if the person giving it is competent. Although allegedly informed consents are routinely tendered, there are nonetheless serious problems with the concept of competence as it stands. First, conceptual work upon competence is incomplete: the concept is unanalyzed and no logic of competence has been identified. It is thus virtually impossible to reliably discern who is (not) competent. Traditional work on competence has explicated three dichotomies from which the necessary conditions for the possibility of competence will be identified, viz., that competence (1) is either a global or a specific notion; (2) is present in varying degrees or in virtue of a threshold; (3) and may or not include appeals to consequences. Past efforts have failed to notice a fourth dichotomy: competence as an affective or cognitive notion. Failure to designate the appropriate arms of these dichotomies is responsible for there being, at present, no reliable test for competence. The inadequacies of a highly regarded particular test for competence, the mental status examination, are examined in light of this failure. Competence is located within the rule-governed practice of informed consent. That practice and hence, competence, is justified through a Kantian analysis of respect for persons. This analysis reveals that the logic of competence requires assessment in terms of (1) specific rather than global concerns; (2) degrees of ability rather than a threshold; (3) both cognitive and affective abilities; and (4) no appeal to consequences. Based upon the analyses of consent as an example of decision making within the practice of informed consent and of respect for persons, the capacities which jointly comprise competence are identified. These are the capacities to receive, recognize, and retrieve information; to reason about, relate to oneself, and rank options; to choose among alternatives; and, under certain circumstances, to defend one's choice. Identification of the logic of competence and explication of and justification for the capacities that comprise competence to consent provide a conceptual foundation for the crucial concept of competence that the informed consent process currently lacks. It should facilitate construction of a test for competence.

This thesis concerns alternative concatenating operations in extensive measurements and the degree to which concatenating operations are matter of convention. My arguments are directed against Ellis' claim that what prevents us from choosing alternative ways of combining extensive quantities is only convenience and simplicity and that the choice is not based on empirical reasons. My first argument is that, given certain relational theories of measurement, there can be no more than one concatenating operation per quantity; because combining operations are the only conclusive distinguishing characteristic among distinct extensive measurements and thus the only thing that can serve as an indicator for the identity of a quantity. Rectangular and collinear concatenation, for example, cannot both be used as a way of combining lengths. However, rectangular concatenation could be used to measure some other extensive quantity since it fulfills the necessary conditions for adequate numerical assignment. For those that adopt theories of measurement which can support the claim that dinches measure length, I demonstrate, in the second argument, that rectangular concatenation would be a bad alternative and thus no alternative at all. Implementation of rectangular concatenation requires a new science; a science compatible with dinches violates present invariance principles and a new set must be provided, if possible. It is not clear that there is a set of invariance principles compatible with dinches which also gives basis for a science that explains the phenomena as well as the old one. Moreover, new invariance principles would be unintuitive and would require that certain fundamental concepts change their meaning. For these reasons the choice between them is guided by a number of empirical reasons and is not only a matter of convention.

Through close critical analyses of Hume's texts I have attempted to develop a new interpretative framework that makes Hume's arguments and positions more accessible, if not more plausible. More positively, The Reluctant Revolutionary is an attempt to defend what may be called a subjectivist interpretation of Hume's views on necessary connection. My central thesis is the suggestion that Hume identifies necessary connection or power with a specific psychological disposition of the mind--as he puts it in the Treatise: necessary connection 'is a determination of the mind to carry our thoughts from one object to another.' (T 165) But why would Hume subscribe to this radical thesis, one may wonder? A large part of my discussion is an attempt to answer this vital question. The book consists of four components. In Chapter One (i) I begin with the argument that Hume views his discussion of necessary connection as central to the Treatise--if not as its centerpiece, and (ii) then go on to try to place this discussion in its immediate philosophical context which is the discussion on causality. After further deliberations on these two issues, in Chapter Three I proceed to outline, and critically evaluate the immediate arguments relied on by Hume to establish his view of necessary connection. For the most part, these do not strike me as convincing arguments. Finally, in Chapter Four I broaden my analysis of Hume's view of necessary connection, and try to develop an account of Hume's conception of the problem that motivates his radical view of necessary connection. As I try to point out, Hume is driven by an irrepressible urge for clarity and rigour in metaphysics--an urge that manifests itself, as I attempt to show, both in the radical nature of Hume's proposals, and in his depiction of the problem of necessary connection. For Hume depicts the problem of necessary connection as a dilemma, according to which metaphysicians either (a) concede that the term 'necessary connection' is meaningless (by virtue of the non-existence of a requisite impression) (b) or accept that this term actually refers to a particular subjective psychological disposition, and not, for instance, to some external phenomenon. This chapter closes with a consideration of this dilemma, and its role in Hume's postulation of a radical view of necessary connection. (Abstract shortened with permission of author.)

A pure coherence theory of empirical justification claims that the justification of empirical beliefs is based solely on internal relations. This claim gives rise to the input objection, which states that pure coherentism allows empirical justification to be cut off from the world. Laurence BonJour and Michael Williams attempt to rebut the input objection. BonJour does so by means of cognitively spontaneous beliefs. The arguments for these beliefs are, however, fraught with too many difficulties for the notion of cognitively spontaneous beliefs to be tenable. Williams challenges the input objection by means of a dilemma, claiming that either the input objection is unintelligible, or epistemic beliefs provide the pure coherentist with a ready answer to the objection. The dilemma is unsuccessful since it fails to take into account all of the plausible conceptions of the world that are available. The input objection therefore remains a problem with which these coherentists must wrestle.