Joshua Rowan Thorpe

The disagreement between generalists, who claim that conspiracy theories can be evaluated as a class, and particularists, who claim that each conspiracy theory must be evaluated on its own merits, has been one of the main dividing lines in the literature on conspiracy theories, although it has recently been suggested that consensus has settled in favour of particularism. In this paper we first argue that as it stands this disagreement is merely verbal: both sides are correct, given what they mean by ‘conspiracy theory’. We then revive a substantial version of the debate by adopting the project of analysing the ordinary concept of a conspiracy theory, which offers clear criteria on a correct definition. Our proposal is that the definition that best fits these criteria is one on which conspiracy theories are undermined by the testimony of epistemic superiors. Importantly, our definition implies the truth of generalism. While the paper is centrally concerned with advancing a novel view on the nature of conspiracy theories, its broader interest lies in the important connections it draws between this topic and recent discussions of epistemic authority, testimony, and defeat.

Putnam’s vat argument is intended to show that I am not a permanently envatted brain. The argument holds promise as a response to vat scepticism, which depends on the claim that I do not know that I am not a permanently envatted brain. However, there is a widespread idea that the vat argument cannot fulfil this promise, because to employ the argument as a response to vat scepticism I would have to make assumptions about the content of the premises and/or conclusion of the argument that beg the question against the sceptic. In this paper, I show that this idea is mistaken.

Davidson argues that his version of interpretivism entails that sceptical scenarios are impossible, thus offering a response to any sceptical argument that depends upon the possibility of sceptical scenarios. It has been objected that Davidson’s interpretivism does not entail the impossibility of sceptical scenarios due to the possibility that interpreter and speaker are in a shared state of massive error, and so this response to scepticism fails. In this paper I show that the objection from the possibility of shared error rests on a misunderstanding of Davidson’s interpretivist position. Properly understood, Davidson’s view does entail that sceptical scenarios are impossible. I also give a reason independent of its anti-sceptical implications to prefer Davidson’s interpretivism over the version of interpretivism erroneously attributed to him by those who object to his anti-sceptical argument.

A general trend in recent philosophical and empirical work aims to undermine various traditional claims regarding the distinctive nature of self-knowledge. So far, however, this work has not seriously threatened the Cartesian claim that (at least some) self-knowledge is immune to the sort of sceptical problem that seems to afflict our knowledge of the external world. In this paper I carry this trend further by arguing that the Cartesian claim is false. This is done by showing that a familiar sceptical argument that targets my knowledge of the external world can be adapted to target my belief that I exist, along with any of my self-knowledge that I know entails my own existence. Thus, my self-knowledge and my knowledge of the external world are subject to the same sort of sceptical problem.

The enigmatic few paragraphs around pages 14-15 of Reason, Truth and History that offer the “proof” of our title have probably generated more interpretative reaction than any other short argument in recent philosophy. Their achievement and significance, however, have remained stubbornly controversial. We reckon that, through the settling dust of the debates over the last 35 years, it is now possible to make out the contours of a reasonably clear set of lessons. Stable answers are in prospect to each of the three main issues: Does the proof work? If so, what exactly does it show? And of what, if any, significance, metaphysical or epistemological, is the result? We outline these answers in this paper.

The conclusion of the McKinsey paradox is that certain contingent claims about the external world are knowable a priori. Almost all of the literature on the paradox assumes that this conclusion is unacceptable, and focuses on finding a way of avoiding it. However, there is no consensus that any of these responses work. In this paper I take a different approach, arguing that the conclusion is acceptable. First, I develop our understanding of what Evans calls merely superficially contingent a priori knowledge, and explain why there is no reason to deny that merely superficially contingent a priori knowledge of the external world is possible. I then argue that, properly understood, the conclusion of the McKinsey paradox is that merely superficially contingent knowledge of certain claims about the external world is possible, and so the conclusion is acceptable. Finally, I respond to the two main arguments that the conclusion of the paradox is unacceptable.

In this thesis I give a response to external world scepticism. I first argue that scepticism arises when we accept that it is an empirical question whether I am in a sceptical scenario, that is, a scenario in which my beliefs are coherent, and yet my empirical beliefs are false. The idea that it is an empirical question whether I am in a sceptical scenario gets its plausibility from the realist claim that our empirical beliefs have an objective subject matter. I then attempt to give a response to scepticism that is compatible with this realist claim. Three promising responses to scepticism are considered, but are found to be inadequate. Seeing why these responses are inadequate helps us to appreciate some of the conditions on an adequate response to scepticism. By drawing on the work of Donald Davidson I develop a response to scepticism that is compatible with the realist claim, and that meets these conditions. According to this response, when we get clear about the concept of belief we see that sceptical scenarios are a conceptual impossibility. Thus, just as it is not an empirical question whether I am a married bachelor, it is not an empirical question whether I am in a sceptical scenario, and the argument for scepticism breaks down.

If it works, I can use Putnam’s vat argument to show that I have not always been a brain-in-a-vat. It is widely thought that the vat argument is of no use against closure scepticism – that is, scepticism motivated by arguments that appeal to a closure principle. This is because, even if I can use the vat argument to show that I have not always been a BIV, I cannot use it to show that I was not recently envatted, and it is thought that the claim that I am not justified in thinking that I was not recently envatted is all that the closure sceptic requires. In this paper I first argue that scenarios in which I have been recently envatted are inadequate for the sceptic’s purposes, and so the standard argument that the vat argument is of no use against closure scepticism fails. I then argue that it is not possible to revise the standard argument to meet my objection. I conclude that, if it works, I can use the vat argument as a defence against closure scepticism.