Title: Justification, Probability and Strong vs. Weak External World Skepticism
Abstract: Contemporary discussion of the epistemology of lotteries has raised the possibility that knowledge can come apart from justified high confidence in a true proposition - even in cases where there is no "appeal to false lemmas". This suggests a distinction between two different kinds of external world skepticism. Consider a skeptical hypothesis like PEASOUP: everything outside a 50 foot radius from me is pea soup which forms up around me in such a way as to mimic the behaviour of a persisting physical world.
Weak External World Skepticism holds that we don't know ~PEASOUP
Strong External World Skepticism holds that aren't even justified in assigning high probability to ~PEASOUP
Infamously, one can motivate the *weak* skeptic's claim that we lack knowledge of ~PEASOUP by providing an argument from prima facie attractive premises. Can one do the same for the *strong* skeptic's claim that we aren't justified in being highly confident in ~PEASOUP? I will consider some ways the strong skeptic might try to motivate their signature claim, and tentatively suggest that one cannot. If this hypothesis is correct, I think it suggests a new line of attack on the old problem of external world skepticism.
*[Many philosophers think that you are justified in being very confident that ticket #1 in a fair lottery with a million tickets won't win and betting accordingly, but you don't *know* that ticket #1 won't win (and can't know this, without gathering some further evidence relevant to the case).]
[Also, I've included a link to my slides, which are fairly self explanatory and I'd be grateful for any questions/objections/suggestions emailed to seberry@invariant.org]