It is important to have an adequate model of uncertainty, since decisions must be made before the uncertainty can be resolved. For instance, flood defenses must be designed before we know the future distribution of flood events. It is standardly assumed that probability theory offers the best model of uncertain information. I think there are reasons to be sceptical of this claim. I criticise some arguments for the claim that probability theory is the only adequate model of uncertainty. In particular I critique Dutch book arguments, representation theorems, and accuracy based arguments. Then I put forward my preferred model: imprecise probabilities. These are sets of probability measures. I offer several motivations for this model of uncertain belief, and suggest a number of interpretations of the framework. I also defend the model against some criticisms, including the so-called problem of dilation. I apply this framework to decision problems in the abstract. I discuss some decision rules from the literature including Levi's E-admissibility and the more permissive rule favoured by Walley, among others. I then point towards some applications to climate decisions. My conclusions are largely negative: decision making under such severe uncertainty is inevitably difficult. I finish with a case study of scientific uncertainty. Climate modellers attempt to offer probabilistic forecasts of future climate change. There is reason to be sceptical that the model probabilities offered really do reflect the chances of future climate change, at least at regional scales and long lead times. Indeed, scientific uncertainty is multi-dimensional, and difficult to quantify. I argue that probability theory is not an adequate representation of the kinds of severe uncertainty that arise in some areas in science. I claim that this requires that we look for a better framework for modelling uncertainty

This thesis has two goals. Firstly, we consider the problem of model selection for the purposes of prediction. In modern science predictive mathematical models are ubiquitous and can be found in such diverse fields as weather forecasting, economics, ecology, mathematical psychology, sociology, etc. It is often the case that for a given domain of inquiry there are several plausible models, and the issue then is how to discriminate between them – this is the problem of model selection. We consider approaches to model selection that are used in classical [also known as frequentist] statistics, and fashionable in recent years methods of Akaike Information Criterion [AIC] and Bayes Information Criterion [BIC], the latter being a part of a broader Bayesian approach. We show the connection between AIC and BIC, and provide comparison of performance of these methods. Secondly, we consider some philosophical arguments that arise within the setting of the model selection approaches investigated in the first part. These arguments aim to provide counterexamples to the epistemic thesis of scientific realism, viz., that predictively successful scientific theories are approximately true, and to the idea that truth and predictive accuracy go together. We argue for the following claims: 1) that none of the criticisms brought forward in the philosophical literature against the AIC methodology are devastating, and AIC remains a viable method of model selection; 2) that the BIC methodology likewise survives the numerous criticisms; 3) that the counterexamples to scientific realism that ostensibly arise within the framework of model selection are flawed; 4) that in general the model selection methods discussed in this thesis are neutral with regards to the issue of scientific realism; 5) that a plurality of methodologies should be applied to the problem of model selection with full awareness of the foundational issues that each of these methodologies has.

"Partial realism" is a common position in the contemporary philosophy of science literature. It states that the "essential" elements of empirically successful scientific theories accurately represent corresponding features the world. This thesis makes several novel contributions related to this position. Firstly, it offers a new definition of the concept of “empirical success”, representing a principled merger between the use-novelty and unification accounts. Secondly, it provides a comparative critical analysis of various accounts of which elements are "essential" to the success of a theory, including structural realism and the divide et impera strategy. A novel account of essentialness, entitled the “empirically successful sub-theory "account", is defended. Thirdly, it is argued that the realism/anti-realism debate should put to the side metaphysical questions and focus instead on partial realism's commitment to the continuity of science. Because this commitment lacks metaphysical implications, it is referred to as "deflationary realism". Anti-realists cannot reject deflationary realism as a matter of a priori principle; its overall viability (and therefore that of partial realism) can therefore only be assessed by a careful examination of the history of science. Finally, another consequence of partial realism, named "partial rationalism", is defended. Partial rationalism states that, in cases where several competing theories have been suggested, scientists are rational just in case they accept the essential elements of each of the scientific theories on offer. This novel position subverts the existing literature on scientific "revolutions", as it sometimes demands that scientists devise a synthesis between competing scientific theories, instead of "choosing" only one. The philosophical points defended in this thesis are illustrated and supported by case studies from the history of science, including Fresnel’s wave theory of light, the Copernican revolution, the "neo-Darwinian synthesis" in evolutionary biology, the "prion revolution" in molecular biology, the miasma theory of disease, and the chemical revolution.

Taking Savage's (1954) subjective expected utility theory as a starting point, this thesis distinguishes three types of uncertainty which are incompatible with Savage's theory for small worlds: ambiguity, option uncertainty and state space uncertainty. Under ambiguity agents cannot form a unique and additive probability function over the state space. Option uncertainty exists when agents cannot assign unique consequences to every state. Finally, state space uncertainty arises when the state space the agent constructs is not exhaustive, such that unforeseen contingencies can occur. Chapter 2 explains Savage's notions of small and large worlds, and shows that ambiguity, option and state space uncertainty are incompatible with the small world representation. The chapter examines whether it is possible to reduce these types of uncertainty to one another. Chapter 3 suggests a definition of objective ambiguity by extending Savage's framework to include an exogenous likelihood ranking over events. The definition allows for a precise distinction between ambiguity and ambiguity attitude. The chapter argues that under objective ambiguity, ambiguity aversion is normatively permissible. Chapter 4 gives a model of option uncertainty. Using the two weak assumptions that the status quo is not uncertain, and that agents are option uncertainty averse, we derive status quo bias, the empirical tendency for agents to choose the status quo over other available alternatives. The model can be seen as rationalising status quo bias. Chapter 5 gives an axiomatic characterisation and corresponding representation theorem for the priority heuristic, a heuristic which predicts binary decisions be- tween lotteries particularly well. The chapter analyses the normative implications of this descriptive model. Chapter 6 defends the pluralist view of decision theory this thesis assumes. The chapter discusses possible applications of the types of uncertainty defined in the thesis, and concludes.

It is my contention that the presence of Nietzsche in FCM is of central importance for both reading this text, and for understanding the stakes of Heidegger's Auseinandersetzung with Nietzsche. This thesis will, therefore, endeavour to re-locate FCM within the Heideggerian corpus via a reading of the text “as a whole”. The focus of this re-location, and indeed the locus of this reading as a whole, is the contention that FCM is part of a Heideggerian Auseinandersetzung with Nietzsche. This task is a response to the majority of existing readings of the 1929/30 lecture course that regard it as a fragmented work, and subsequently focus on its two most novel elements in isolation (namely Heidegger's analysis of boredom and the supposed “theoretical biology” that comprises the majority of 'Part Two'). When read out of context, and as a fractured project, FCM appears to straightforwardly reassert the primacy of man in western metaphysics, thus succumbing to the pitfalls of a “metaphysics of subjectivity”. On the basis of a reading of Nietzsche's presence in FCM, I will situate 'Part Two' within a philosophical and hermeneutical context not established in other readings heretofore. This opens the space for the genuine philosophical trajectory of the text to emerge, namely the grounding of a confrontation (an Auseinandersetzung) with Nietzsche as the site of contemporary philosophising. Taking up this trajectory allows for a re-invigorated understanding of the development of Heidegger's Nietzsche reading, and a deepening of the case regarding the centrality of Nietzsche for Heidegger's own thinking.

This thesis consists in emphasizing an all too often overlooked Deleuzian redefinition of the concept of ‘hierarchy’. Deleuze re-creates the sense of this old concept in order to break with the traditional representations of verticality, which have predominantly led philosophy back to the transcendence of established powers and the abstractions of opinion. To the order of representation and transcendence, always implicating the ideal of a unity as criterion of judgment and perception, Deleuze opposes a complex order in becoming. From this perspective, hierarchy no longer concerns the ontological separation between being and beings, or between thought and what it thinks. Rather, hierarchy, inasmuch as it is now integrated within the differential order of pure immanence, refers to the unequal perspectives that make up the extreme singularity of individuals as various modes of life. In addition to being an ontological feature of life as self-differing power, hierarchy constitutes a vital problem for thought, for it posits the question of exploring to what extent and by which means beings can actively possess their vitality and fully accomplish their power. It is through the problem of hierarchy, conceived as ethical differentiation of modes of existence and values, that the problem of freedom and of its relative degrees acquires, in Deleuze, a very concrete sense. It becomes one with an art of individual and collective experimentation, by which thought learns how to free itself from enslaving fictions in favour of a more intense existence.

My dissertation concerns post Kripkean debates which locate normativity not as a feature of linguistic meaning but as applicable to mental content. My aim is to identify a clear sense in which the thesis is plausible and to defend the thesis against recent criticisms. In order to do this, I will consider the two main premises that the normativity thesis is based upon, namely, (a) that belief is conceptually priority to desire and (b) that belief is a normative concept. Most criticisms of the normativity thesis in the literature argue against the latter premise, namely, the normativity of belief thesis. I first argue that recent objections against the priority of belief to desire do not undermine the normativity thesis in the case of mental content. I then concentrate on the normativity of belief to defend the thesis. I will consider the logic of the normativity of belief thesis and suggest viable formulations of the thesis. I will also defuse recent objections against the normativity of belief thesis and I establish a new argument for the thesis.

There is a double meaning in the name of this thesis. This duality emerges from how the term ‘hermeneutics’ can be applied. In one sense the hermeneutics of this thesis is a textual interpretation of the philosophical history of ontology. This is an interpretation of ontological theory from its genesis with the Pre-Socratic concern with the ‘question of being’ and onwards through its salient historical developments up until the early twentieth century. The thesis interprets these developments as nevertheless maintaining a foundational understanding of ‘being’ as ‘quiddity’ or ‘what-ness’. While the ontological tradition diverges over disagreements about ‘realism’, ‘idealism’, or ‘nominalism’, for example, these disagreements are interpreted as having an unchanging understanding of ‘being’ in terms of ‘what-ness’ that unites them. Furthermore, this traditional understanding of ‘being’ as ‘what-ness’ is documented as having an implicit connection to a conceptual model of human understanding that divides the knowing subject from the known object. In opposition to a prominent interpretation that identifies this model as a Cartesian development, it is rather presented that it has roots that can be found within the philosophy of Plato. Moreover, this model is interpreted as being contingent on the technological development and adoption of literacy that predicated an emergent and reflexive understanding of the ‘what-ness’ of the self-subject. However, this textual hermeneutics of the history of ontology also presents the challenge to understanding ‘being’ as ‘what-ness’ that occurred in the early twentieth century. This is found in the philosophy of Martin Heidegger, and in particular in his treatise Being and Time. This alternative understanding of ‘being’ is interpreted as presenting an ontology of ‘how-ness’. This understanding of ‘being’ as ‘how-ness’, as opposed to ‘what-ness’, is presented through Heidegger’s introduction of the concept of the ‘ontological difference’. This concept, it is shown, enables Heidegger’s understanding of human existentiality as self-interpretation. In addition, the inheritance of this ontological thesis of self-interpretative existence is traced from its phenomenological, hermeneutic, and existentialist roots. This includes the analysis of the ideas of such scholars as Friedrich Schleiermacher, Wilhelm Dilthey, and Edmund Husserl. Through documenting this provenance, the duality of this thesis’ title is demonstrated. It is not only a textual hermeneutics that is presented in this treatise, but also an example of hermeneutic phenomenology. Hermeneutic phenomenology, as Heidegger argued, is presented as the methodology for an ontology that understands human existentiality as self-interpretative. This methodology is analysed, and differing interpretations of its processes are critiqued. Furthermore, by interpreting human existentiality as hermeneutic, Heidegger’s understanding of ‘being’ as temporal is elucidated. The thesis of the temporality of human existentiality is then explained in terms of its structure as ‘being-in-the-world’. The equiprimordial characteristics of ‘being-in-the-world’ are analysed, such as ‘who-ness’, ‘there-ness’, and ‘world-ness’, and these are shown to together constitute human existentiality. The thesis then concludes by demonstrating how this hermeneutic phenomenology of ontological ‘how-ness’ also enables the explication of the temporality of technological existentiality.

published_or_final_version / abstract / toc / Medicine / Master / Doctor of Medicine

published_or_final_version / Medical Sciences / Master / Master of Medical Sciences