On the Possibility of Skeptical Scenarios

Abstract

It is generally accepted that skeptical scenarios must be possible to raise legitimate skeptical doubt. I argue that if the possibility in question is supposed to be genuine metaphysical possibility, the skeptic's reasoning does not straightforwardly succeed. I first motivate the metaphysical possibility requirement on skeptical scenarios: it's a plausible position that several authors accept and that a family of prominent views-sensitivity, safety, relevant alternatives-are committed to. I argue that plausible constraints in modal epistemology show that justification for believing that certain global skeptical scenarios are metaphysically possible rests on some justified beliefs about the external world, and that this undermines the skeptical argument. While there may still be local skeptical challenges, skeptics cannot appeal to the metaphysical possibility of skeptical scenarios to generate global external world skepticism.Consider this picture of the skeptical dilemma: Descartes sits in his armchair, wondering what the world is like, and worried whether it is as it seems to be. He realizes that there are many ways the world could bemany possible ways for the world to be-that he lacks the resources to choose between. Since all the possibilities he is considering include his having experiences like the ones he has actually had, experience cannot help choose between them.In this paper I argue that if the purported possibilities in the above picture are supposed to be genuine metaphysical possibilities, this line of skeptical reasoning does not straightforwardly succeed. The above sketch assumes that Descartes can know the metaphysically possible ways the world might be from the armchair. 1 That assumption raises questions about modal epistemologyconceivability and possibility, intuitions about possibility-that have received extensive treatment in the philosophy of mind literature. I argue that plausible constraints in modal epistemology show that justification for believing that certain global skeptical scenarios are metaphysically possible rests on some justified beliefs about the external world, and that this undermines the skeptical argument. While there may still be local skeptical challenges, skeptics cannot appeal to the metaphysical possibility of skeptical scenarios to generate global external world skepticism.

The Appearance of Skepticism: Possibility, Conceivability and Infinite Ascent

“…6 Hereafter, I shall take SKP-0 to be equivalent to the formulations above: it is possible that I am a brain in a vat/that nothing is as it appears to be, etc. 7 For convincing arguments that the modality involved cannot be epistemic see Levin (2000), Kung (2011), andEcheverri (2017). 8 As I clarify below, here I treat SKP-0 as a presupposition, so my treatment of it differs from Levin's, who calls it a "premise" (2000, 423) of the skeptical argument.…”

Brains in a VAT and memory: How (not) to respond to Putnam's argument

“…This is often taken to require that the sceptical scenario must be easily conceivable, that it must be consistent with our best philosophical and scientific theories about how the mind works and that it does not merely stipulate that, but explains how and why the beliefs of its victim fall short of knowledge (cf. Cross 2010, Kung 2011). An example for a scenario that does not meet this constraint is the jinn in a lamb scenario, a scenario which suggests you might be ghost living in a lamb waiting to be freed by Aladdin.…”

Global Scepticism, Underdetermination and Metaphysical Possibility

“…But it seems implausible that these examples could give S some degree of justification for the claim that it is metaphysically possible that an extraordinary deceiving situation -one that could never be detected by S -actualises. 36 Van Inwagen 2001and Kung (2011), among others, emphasise that we seem to be able to know the modal status of propositions when they describe situations similar to those of ordinary life. A nonimplausible explanation of this ability is roughly the following: in these cases, our mind recombines into novel scenarios things that we know or we have justification to believe to exist and to have certain properties on the grounds of our experience.…”

“…A sceptic sympathetic to recombinatorialism might argue that we possess some degree of justification for claiming that sceptical scenarios that include no outlandish entities -such as disembodied souls or vicious demons -are metaphysically possible (cf. Kung 2011). This might be the case with the brain-in-a-vat scenario and the Matrix scenario.…”