Associate Professor, Department of Philosophy, Lewis & Clark College

Frege-Geach Redux

Added on by jay odenbaugh.
Geoffrey Sayre-McCord's "Realist" Interview

Geoffrey Sayre-McCord's "Realist" Interview

Here is a favorite moral argument of all time. 

  1. It is wrong to tell lies.
  2. If it is wrong to tell lies, it is wrong to get your little brother to tell lies.
  3. ∴ It is wrong to get your little brother to tell lies.

First, According to Gibbard, for any normative sentence we replace those predicates with N-corresponding predicates (e.g. N-required, N-optional, N-forbidden). Second, the normative content of such sentences is this: holds at <w, n> iff S_n holds at w. Thus, here is the paraphrase: 

  1. Feeling guilt and resentment for lying is N-permitted at w
  2. If feeling guilt and resentment for lying is N-permitted at w, then feeling guilt and resentment for getting little brother to lie is N-permitted at w
  3. ∴ Feeling guilt and resentment for getting little brother to lie is N-permitted at w.

An argument is Gibbard-valid iff there is no <w, n> where the premises hold and yet the conclusion. Since there is true of (1), (2), (3), we have a valid argument. 

Question: Do you think Gibbard resolves the Frege-Geach problem? Why or why not?