The Ockham Society (Thursday - Week 4, TT19)

Ockham Society

Talk 1 - Sebastian Liu: 'The Skeptic and the Akrates'

The external world skeptic denies that it is rational for me to believe that I have hands. For if it is rational for me to believe I have hands, then it must be rational for me to believe that I am not a (bodiless) brain in a vat. But – according to the skeptic – my evidence is perfectly consistent with my being a brain in a vat. And so it must not be rational for me to believe that I have hands after all.

Implicit in the skeptical argument is the thought that whether I am in the skeptical case my evidence is limited to how things appear to me. The externalist about evidence denies this: while in the skeptical case, my evidence is limited to propositions about how things appear, in the non-skeptical case, my evidence includes propositions about the external world. As long as my perceptual faculties are reliable, I can receive conclusive evidence that I have hands when I see them. So the skeptical argument is unsound.

The committed skeptic will likely deny externalism about evidence. Perhaps such a skeptic is beyond saving. But even the modest skeptic who is willing to grant evidence externalism remains unsatisfied: that our evidence can include propositions about the external world does nothing to establish the reliability of our faculties. Plausibly, if the proposition that I have hands becomes part of my evidence when I see that I have hands, then I need to have evidence about the reliability of my perceptual faculties. Hallucinating hands does not give me evidence about the external world, irrespective of whether I am in the non-skeptical case. All that I can claim is that if my perceptual faculties are reliable, then it is rational for me to believe that I have hands. To deny this is to maintain that it can be rational for me to believe something akin to 'p, and I am unsure whether my evidence supports believing that
p', or even 'p, but my evidence does not support that p'. This looks like a paradigm of irrationality. The akrates defends that this combination of beliefs can be rational. This talk examines the plausibility of such a response to the skeptic.


Talk 2 - Joshua Pearson: 'Contextualism and Defeat'

Contextualists, like Greco and Neta, have argued that Contextualism (and in particular contextualism about 'evidence') can solve problems concerning defeat in interesting ways. In the first part of the talk, I'll argue that this isn’t true. These contextualists attempt to explain defeat through context-shifts. But context-shifts require a shift in speakers' epistemic standards, whereas defeat intuitively does not. 

In the second half of the talk, I'll tie the above issue to Salow's paper 'Elusive Externalism'. Salow argues that contextualism about evidence can reconcile denying the negative access principle (i.e. if e is not part of X's evidence, then X has conclusive evidence that e is not part of her evidence) with the claim that akratic subjects (i.e. subjects who believe something like 'p, but I shouldn't believe that p') are irrational. Salow's reconciliation suffers from a similar issue concerning epistemic standards that the above contextualist accounts of defeat face. I'll explore what options, if any, the contextualists have for vindicating Salow's strategy.


Ockham Society Convenor: Sean Costello | Ockham Society Webpage