Central Problems of Philosophy

Prof. Stephen Schiffer

Fall `98

Handout 4

1. A knows that S.
2. Necessarily, for any agent x and any proposition p, x knows p iff .... [Paper topic on the completion of this schema: see the entries, and their bibliographies, for "The Gettier Problem" and "Propositional Knowledge" in J. Dancy and E. Sosa (eds.), A Companion to Epistemology (Blackwell, 1992).]
3. Necessarily, for any agent x and any proposition p, x knows p only if (1) p is true.
4. Necessarily, for any agent x and any proposition p, x knows p only if (1) p is true; (2) x believes p.
5. Necessarily, for any agent x and any proposition p, x knows p only if (1) p is true; (2) x believes p; (3) x is justified in believing p
6. Necessarily, for any agent x and any proposition p, x knows p only if (1) p is true; (2) x believes p; (3) x is epistemically justified in believing p.
7. If two hypotheses equally well explain evidence E, then E can’t be taken as good evidence for either hypothesis.
8. Initial reconstruction of Descartes’s argument (with BIV substituted for the dream and evil demon hypotheses):
1. The fact that I’m having the experiences I’m now having is entirely consistent with my being a bodiless brain in a vat (a BIV).
2. So, I don’t know anything based on sense experience, such as that I now have hands.
9. Our official representation of the Cartesian skeptical argument:
1. I don’t know that I’m not a BIV.
2. If I don’t know that I’m not a BIV, then I don’t know that I have hands.
3. Therefore, I don’t know that I have hands.
10. Paper topic on the status of the Cartesian skeptical argument: Keith DeRose, "Solving the Skeptical Problem," The Philosophical Review, 104 (January 1995): 1-52, and Stephen Schiffer, ""Contextualist Solutions to Scepticism," Proceedings of the Aristotelian Society for 1995/96: 317-333.