[FOM] Free Logic

[Dana Scott]

Ten years apart, I wrote two papers:

Dana Scott. "Existence and description in formal logic." In: Bertrand Russell: 
Philosopher of the Century, edited by R. Schoenman. George Allen & Unwin, London, 
1967, pp. 181-200. Reprinted with additions in: Philosophical Application of
Free Logic, edited by K. Lambert. Oxford Universitry Press, 1991, pp. 28 - 48.

Dana Scott. "Identity and existence in intuitionistic logic." In: Applications of 
Sheaves, edited by M. Fourman & D. Scott. Durham Proceedings (1977), Springer-Verlag, 
LNM vol. 753, 1979, pp. 660-696.

Not everyone liked my formalization.  My rule-of-thumb was that
free variables allowed substitution by any term existing or not.
The bound variable though ranged over existing things.  I allowed
any number of non-existents and equality did not imply existence.
And an empty domain was OK.

I can send a PDF of either paper upon request.