Name: _______________________________

1. What is the difference between a sentence and a term?


A sentence is either true or false, a term refers to an object.
 
 

2. Is truth a semantic or syntactic concept?


We understand truth to be a relation between sentences and worlds, so it is a semantic concept.
 
 

3. Determine whether the propositional formula `A --> ( B --> A )' is a tautology or not.


A B | A --> ( B --> A )
--+----
T T | T
T F | T
F T | T
F F | T
Yes, it is a tautology.
 
 

4. Every syllogism was given a particular name to identify it. Give an example of such a name that was given to a syllogism.


The syllogism of figure 1 with `All' quantifiers is called Barbara. The other names are on page 50 of Handout #19.
 
 

5. What is the biggest drawback of Aristotle's theory of syllogisms?


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.