[FOM] 820: Sugared ZFC Formalization/2

[Harvey Friedman]

There is a lengthy article on Free Logic and history thereof at
https://plato.stanford.edu/entries/logic-free/ with perhaps relevant
references going back to 1951.

Perhaps people will want to comment on that article.

Harvey Friedman

On Tue, Jun 19, 2018 at 8:22 AM, Tennant, Neil <tennant.9 at osu.edu> wrote:
>
> Harvey in effect relies on the scope distinctions that can be made fully explicit by the following use of bound variables to indicate term-insertions:
>
> t_x (x=x)         false if the term t does not denote; true if the term t does denote
>
> ~ t_x (x=x)      true if the term t does not denote; false if the term t does denote
>
> t_x ~(x=x)       false if the term t does not denote; false if the term t does denote
>
> The free logic that captures these intuitions about term-denotations and truth-conditions is set out in my paper
>
> Natural deduction for first order logic with identity, descriptions and restricted quantification’, in Contributed Papers of the 5th International Congress of Logic, Methodology and Philosophy of Science, London, Ontario, 1975, pp. I 51-2.
>
> See iterm 123 at https://u.osu.edu/tennant.9/publications/
>
> Neil
>