[FOM] "Literal"

[William Tait]

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On Sep 6, 2006, at 9:26 AM, Charles Silver wrote:

> 	Can anyone tell me who first defined the term "literal" for a
> sentence in propositional logic that's either an atomic sentence or
> the negation of one?   The earliest occurrence of the word used this
> way that I've found is in Quine, 1959: "A way to simplify truth
> functions".   I think it's an unfortunate name for this kind of
> sentence and would welcome a better one, especially if it precede
> Quine's.

I have used the term "prime" for atomic and negated atomic formulas--- 
e.g. in my paper "Normal derivability in classical logic" in 1967,  
and so not predating the Quine and (shame on you Martin) Davis-Putnam  
strange use of the term "literal". The motivation was (is) that the  
composite formulas are built up from the prime ones by means of the  
lattice operations of disjunction, conjunction, and the quantifiers  
(if we identify formulas with their De Morgan equivalents).

Regards,

Bill