Three Conceptions of Modal Realism

Divers, John (1990) Three Conceptions of Modal Realism. PhD thesis, University of Glasgow.

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The thesis is divided into three sections. The first of these is a critique of the conceptions of modal realism due to Lewis; the second, a critique of that due to McGinn. The third section comprises the development and initial evaluation of a third conception of moral realism which I term secondary modal realism. In Section One of the thesis [Ch.1- Ch.5] I argue against the acceptability of the objectual modal realism of David Lewis and I argue (tentatively) for one theory of the meaning of possible world statements which is consistent with this denial of the existence of possible worlds. Chapters 1- 4 concern the former argument, Ch.5 concerns the latter. In Ch.1, I argue that there is no genuine semantic utility afforded by the adoption of realism about possible worlds. The case is (i) that the genuine semantical utility which does accrue via the ontological commitment to possible worlds can be had without that ontological commitmment and (ii) that other claims to semanti utility which are associated with possible world semantics do not reflect legitimate semantic-explanatory interests. The main part of the discussion of objectual realism - constituted by Chapters 2, 3 & 4 - takes a different turn. Since Lewis is fond of comparing his modal realism to realism about the entities of mathematics, I attempt to show that, on both epistemological and metaphysical grounds, the comparison is quite unfavourable for objectual modal realism. In Ch.2, I defend the objectual modal realist's right to an a priori epistemology of modality in face of Benaceraffs dilemma, but, it is argued in Ch.3, even granted a priority, there is still a serious epistemological difficulty since the internal epistemology of modal realism which is proposed by Lewis is seriously flawed. In Ch.4, it is argued that there is at least one important metaphysical consideration which militates against an ontological commitment to worlds but which does not appear to have the same impact re. mathematical ontology, viz: that the mooted possible worlds are identification- transcendent. Having made the case for anti-realism about possible worlds I am concerned in Ch.5 with the outline of a theory of the meaning of possible world statements which is consistent with this ontological position. I argue for the unacceptability of a theory, outlined by Forbes, which depends upon the claim that possible world statements do not mean what they appear to mean. I then counterpose the options of an error theory and a metaphor theory of world-talk arguing that while both of these are prima facie tenable, the latter is preferable. In Section Two of the thesis [Ch.6 - Ch.9] I deal with the non-objectual modal realism of McGinn. Having set out the salient theses of McGinn's conception of modal realism [Ch.6], the critique of this conception follows. Ch. 6: the variety and resources of anti-realisms about modality are seriously underestimated by McGinn. In particular the option of anti-realism based on the strategy of proposing a sceptical solution as a response to a sceptical paradox is ignored. Ch.7: McGinn proposes that the only defensible form of modal realism consists in endorsing the thesis of supervenience (without reduction) of the modal on the actual. However, the discussion of supervenience fails to acknowledge many of the difficulties associated with the application of supervenience and related theses in the modal case. Furthermore, there is every reason to believe that acceptance of modal/actual supervenience involves no commitment to modal realism. Ch.8: consideration of the issues that flow from the discussion of the thesis of supervenience should point towards a central question of modal epistemology i.e. whether modal knowledge is attainable by conceptual means alone. However, McGinn's discussion of supervenience leads him away from this central question and as a result he mislocates the problematic nature of modal epistemology in the claim that we cannot represent modal facts as causally explaining our knowledge of them. Ch.9:The modal realism that McGinn offers is wholly unacceptable since it provides neither a clear conception of the truth-conditions of modal statements nor any account of how we detect modalities. The realism he offers is redolent of sceptical paradox and seems ripe for an anti-realist treatment in the form of a sceptical solution. Hence, the upshot of the first two sections is that the existing conceptions of modal realism, i.e. those of Lewis and of McGinn respectively, are indefensible. In Section Three of the thesis [Ch.10 - Ch. 12] the aim is to characterize and evaluate a third conception of modal realism - secondary modal realism. This project is inspired by (i) McDowell's secondary quality conception of moral reality and (ii) the observation of crucial similarities between the failings of more traditional conceptions of moral realism and those conceptions of modal realisms dealt with above. In Ch.10, I argue that anthropocentricity as opposed to perceptibility is the feature of paradigmatic secondary properties which is an appropriately generalizable feature of secondary realism and that a proper conception of the standard of correctness for secondary property judgments facilitates the extrapolation of that standard to the cases of moral and modal judgement. (Abstract shortened by ProQuest.).

Item Type: Thesis (PhD)
Qualification Level: Doctoral
Keywords: Philosophy
Date of Award: 1990
Depositing User: Enlighten Team
Unique ID: glathesis:1990-78377
Copyright: Copyright of this thesis is held by the author.
Date Deposited: 28 Feb 2020 12:09
Last Modified: 28 Feb 2020 12:09

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