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Single Idea 18767

[filed under theme 4. Formal Logic / E. Nonclassical Logics / 6. Free Logic ]

Full Idea

Free logics say 1) singular terms are allowed that do not designate anything that exists; sometimes 2) is added: the domain of discourse is allowed to be empty. Logics with both conditions are called 'universally free logics'.

Gist of Idea

Free logics has terms that do not designate real things, and even empty domains

Source

C. Anthony Anderson (Identity and Existence in Logic [2014], 2.3)

Book Ref

'Bloomsbury Companion to Philosophical Logic', ed/tr. Horsten,L/Pettigrew,R [Bloomsbury 2014], p.67


A Reaction

I really like the sound of this, and aim to investigate it. Karel Lambert's writings are the starting point. Maybe the domain of logic is our concepts, rather than things in the world, in which case free logic sounds fine.

Related Idea

Idea 18768 We cannot pick out a thing and deny its existence, but we can say a concept doesn't correspond [Anderson,CA]


The 9 ideas from 'Identity and Existence in Logic'

Basic variables in second-order logic are taken to range over subsets of the individuals [Anderson,CA]
The notion of 'property' is unclear for a logical version of the Identity of Indiscernibles [Anderson,CA]
Individuation was a problem for medievals, then Leibniz, then Frege, then Wittgenstein (somewhat) [Anderson,CA]
's is non-existent' cannot be said if 's' does not designate [Anderson,CA]
Free logics has terms that do not designate real things, and even empty domains [Anderson,CA]
We cannot pick out a thing and deny its existence, but we can say a concept doesn't correspond [Anderson,CA]
Stop calling ∃ the 'existential' quantifier, read it as 'there is...', and range over all entities [Anderson,CA]
Do mathematicians use 'existence' differently when they say some entity exists? [Anderson,CA]
We can distinguish 'ontological' from 'existential' commitment, for different kinds of being [Anderson,CA]