Logical calculi

 

If you have a logical calculus, it is often assumed that it is legitimate to choose to substitute expressions with meaning for the uninterpreted symbols of the system.

An element of a logical calculus (the propositional calculus) would be this:

If either p or q and not-p then q.

C K(Apq) Np q

It is legitimate it is said to substitute for p a meaningful proposition, and to substitute another meaningful proposition for q.

This then yields the meaningful argument:

If either I'm in bed or you're a Dutchman, and I'm not in bed then you're a Dutchman.

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Are these uninterpreted symbols?

1+1=1

1+0=0

0+1=0

0+0=0

What would be an interpretation?

A true sentence conjoined with a true sentence is a true sentence

A true sentence conjoined with a false sentence is a false sentence

A false sentence conjoined with a true sentence is a false sentence

A false sentence conjoined with a false sentence is a false sentence

I say these things just to start lines of thought.

 

 

 

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