Margaret Schabas

Economists generally understand externalities as unpriced spillover effects. The paradigmatic case is pollution because it is unpriced and affects agents external to the market choices that lead to its production. One solution to an externality is to set a tax on the unpriced activity at the value of the externality in equilibrium. The concept of an externality, however, is notoriously difficult to precisely define and there is a notable absence of consensus among economists. In this dissertation, I offer an analysis of the contemporary treatment of externalities in economic theory and arrive at the following definition: Externalities arise when unpriced activities generate untapped gains from exchange that are associated with untapped welfare gains. It is unclear, however, whether this concept could be instantiated in any concrete sense because gains from exchange often diverge from welfare gains. I suggest possible ways to interpret an externality given this problem, but argue that each interpretation falls short of an adequate account of externalities. The ambiguity of the concept of an externality carries over to attempts to estimate the value of a specific externality. I suggest that this accounts for some of the controversy among both economists and philosophers over one approach to estimating the value of an externality, called the contingent valuation method. Furthermore, this ambiguity renders problematic certain policies, such as the carbon tax, that are intended to internalize an externality. I then argue that the problem of climate change is not merely caused by the presence of externalities, as some economists have suggested. I argue that, even if all externalities were eliminated, a social planner might still bring about a regretful environmental state when they aim to maximize net benefit derived from polluting activities. This is a result of the peculiar cost structure of climate change in which the marginal costs are uninformative of the total costs of polluting. I suggest that, instead of aiming to balance the costs and benefits of polluting, we might need to forgo some of the potential net benefits in order to avoid reaching an irreversible and regretful state.

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This dissertation undertakes a philosophical analysis of “natural capital” and argues that this concept has prompted economists to view Nature in a radically novel manner. Formerly, economists referred to Nature and natural products as a collection of inert materials to be drawn upon in isolation and then rearranged by human agents to produce commodities. More recently, nature is depicted as a collection of active, modifiable, and economically valuable processes, often construed as ecosystems that produce marketable goods and services gratis. Nature is depicted as consisting of various unproduced mechanisms or “natural machines” that are first discovered and then channeled so as to serve human ends. In short, nature as an ideal is a kind of garden that is characterized by natural objects purposefully arranged by intentional human agents. This dissertation first lays out working definitions of the key terms, such as capital and Nature, and then traces the historical roots of natural capital in the writings of eminent classical political economists, such as Adam Smith, John Stuart Mill, and Karl Marx. I then examine the question of substitutes for “critical natural capital”, and argue that the preservation paradox is warranted: no one can restore or preserve a part of Nature without turning it into an artifact. Following the recent work of Debra Satz and Michael Sandel, I finish my dissertation by situating the question of natural capital in the broader context of whether some goods should not be for sale, particularly those I define as Basic Ecological Goods.

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Hume’s theory of belief and his normative standard or ethics of belief are founded on empirically observable, natural principles, principles which have been misunderstood by those who view Hume’s belief theory as one based on the forcefulness and liveliness of our ideas. In this dissertation, I argue that, according to Hume, both factual and value judgments are arrived at via the same basic, natural processes of the mind. All human judgments are ultimately derived from feeling or affect, that is, from internal impressions which arise within the human mind in tandem with, or in reaction to, its experience of ideational content, that is, the “parts or composition of the idea, which we conceive.” According to Hume, then, our feelings, operating in concert with the sensory and cognitive functions of the mind, provide us with our final standards of judgment, whether factual or evaluative. Our ethics of belief—our normative standards of belief—are therefore, like belief itself, more properly ascribable to the “sensitive” or feeling part of our nature, than to the non-affective, rational, or cogitative aspects of cognition. In sum, for Hume, belief is a complex but wholly natural cognitive phenomenon, consisting of, firstly, our experience of ideational content, and secondly, our feeling of cognitive commitment—the feeling of believing in the ideational content experienced. All judgments, factual and evaluative, are composed in this way.

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