> We're drifting fatally off topic here, but: Just as there are some
> statements that cannot be expressed as dyadic predicates, are there also
> those which cannot be expressed as triadic predicates?
> "John gives a book to Mary in exchange for 5 euros"
> If you store the relations "John gives a book to Mary" and "Mary gives 5
> euros to John" how will you know that the 5 euros were payment for the book?
Worse, this happened on a Sunday, in Brussels, while winds were
gusting from the south, and a nearby solicitor wearing a lime green
bowler hat advised them that their transaction was exempt from VAT ;-)
Even allowing relations of arbitrary arity, there are some kinds of
knowledge that can't be expressed in full-blown first-order logic.
For example, Google will find lots of (mostly tedious <wink>)
discussion of the Geach-Kaplan sentence:
Some critics admire only one another.
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