Main.VaguenessEpistemic History
Hide minor edits - Show changes to markup
Changed line 31 from:
to:
Changed lines 9-10 from:
Argument from T-schema
to:
Argument from T-schema
Changed lines 23-26 from:
Margin of error
Higher order vagueness
to:
Margin of error
Higher order vagueness
Changed lines 7-8 from:
Arguments for
to:
Arguments for
Added lines 27-30:
Objections
If vague concepts really do have sharp boundaries, what determines where those boundaries lie?
Added lines 11-12:
No sentence that says something is neither true nor false.
Added lines 23-26:
Margin of error
Higher order vagueness
Changed lines 11-20 from:
- u says that p
# It is not the case that: u is true or u is false.
# If u says that p, then u is true iff p
# If u says that p, then u is false iff ¬p
# u is true iff p (MP 1,3)
# u is false iff ¬p (MP 1,3)
# It is not the case that: p or u is false. (Substitution 2,5)
# It is not the case that: p or ¬p (Substitution 6,7)
# ¬p and ¬¬p (De Morgan 8)
to:
- u says that p
- It is not the case that: u is true or u is false.
- If u says that p, then u is true iff p
- If u says that p, then u is false iff ¬p
- u is true iff p (MP 1,3)
- u is false iff ¬p (MP 1,3)
- It is not the case that: p or u is false. (Substitution 2,5)
- It is not the case that: p or ¬p (Substitution 6,7)
- ¬p and ¬¬p (De Morgan 8)
Changed lines 11-20 from:
- 1. u says that p
*2. It is not the case that: u is true or u is false.
*3. If u says that p, then u is true iff p
*4. If u says that p, then u is false iff ¬p
5. u is true iff p (MP 1,3)
6. u is false iff ¬p (MP 1,3)
7. It is not the case that: p or u is false. (Substitution 2,5)
8. It is not the case that: p or ¬p (Substitution 6,7)
9. ¬p and ¬¬p (De Morgan 8)
to:
- u says that p
# It is not the case that: u is true or u is false.
# If u says that p, then u is true iff p
# If u says that p, then u is false iff ¬p
# u is true iff p (MP 1,3)
# u is false iff ¬p (MP 1,3)
# It is not the case that: p or u is false. (Substitution 2,5)
# It is not the case that: p or ¬p (Substitution 6,7)
# ¬p and ¬¬p (De Morgan 8)
Changed lines 11-20 from:
- 1. u says that p
- 2. It is not the case that: u is true or u is false.
- 3. If u says that p, then u is true iff p
- 4. If u says that p, then u is false iff ¬p
5. u is true iff p MP 1,3
6. u is false iff ¬p MP 1,3
7. It is not the case that: p or u is false. Substitution 2,5
8. It is not the case that: p or ¬p Substitution 6,7
9. ¬p and ¬¬p DeMorgan 8
to:
- 1. u says that p
*2. It is not the case that: u is true or u is false.
*3. If u says that p, then u is true iff p
*4. If u says that p, then u is false iff ¬p
5. u is true iff p (MP 1,3)
6. u is false iff ¬p (MP 1,3)
7. It is not the case that: p or u is false. (Substitution 2,5)
8. It is not the case that: p or ¬p (Substitution 6,7)
9. ¬p and ¬¬p (De Morgan 8)
Changed lines 7-8 from:
to:
Arguments for
Argument from T-schema
- 1. u says that p
- 2. It is not the case that: u is true or u is false.
- 3. If u says that p, then u is true iff p
- 4. If u says that p, then u is false iff ¬p
5. u is true iff p MP 1,3
6. u is false iff ¬p MP 1,3
7. It is not the case that: p or u is false. Substitution 2,5
8. It is not the case that: p or ¬p Substitution 6,7
9. ¬p and ¬¬p DeMorgan 8
Added lines 1-9:
The epistemic conception of vagueness
- Stoic logicians?
- Late 1980s and early 1990s - Roy Sorensen and Paul Horwich
- Timothy Williamson
Philosophy