How Should I Be A Sceptic -- a question of external validation of reasoning
[Introductory note from Jason Pratt: the previous entry in this series of posts can be found here. The first entry can be found here. This entry continues a fourth chapter, begun here. I highly recommend reading at least as far back as this, first.] If my brother, Spencer, thinks he has good grounds for believing that my belief of a snake in the hole has been fostered purely from a cocaine-fit, then he would not (or at least should not) be embarrassed to discover there was, after all, a snake in the hole. He had no good reason to believe the snake was there. Furthermore, my argument that he (and I) should stay away from the hole was ultimately untrustworthy. The form of the argument that we should stay away from the hole was not itself invalid; but without the anchor of rationality at the beginning, there was no good reason to pay attention either to my initial belief ("a snake is in the hole") or to my consequent inferred belief ("we should stay away from the hol...