Subject: HW #5
From: "William J. Rapaport" <rapaport@buffalo.edu>
Date: Wed, 7 Oct 2009 17:28:23 -0400 (EDT)

A student writes:
"I'm having trouble with Question one of the HW.
What's the difference between propositional logic and 'your'
propositional language?"

Reply:  
Propositional *logic* is the reasoning system that involves
truth tables, rules of inference, etc.

It is based on a propositional *language* consisting of letters that
stand for atomic propositions, the connectives, and the rules for
forming molecular propositions.

But *you* get to choose the letters and what they mean in terms of
representing English sentences. So that becomes "your" propositional
language, which may differ from someone else's.

But both of your languages will use the same logic to reason about the
propositions.