Tuesday, August 1 2000
A sentence is either true or false, a term refers to an object.
We understand truth to be a relation between sentences and worlds, so it is a semantic concept.
A B | A --> ( B --> A )
T T | T
T F | T
F T | T
F F | T
Yes, it is a tautology.
The syllogism of figure 1 with `All' quantifiers is called Barbara. The other names are on page 50 of Handout #19.
It is not expressively complete, i.e., it is not general enough to represent all forms of argument. For example, neither `modus ponens', nor the proof of Euclid's first proposition can be formulated as syllogisms.