I'm trying to find a way to automatically convert arbitrary natural language sentences into first-order logic predicates. Although complex, this seems to be feasible to me, through inverse lambda calculus; one of the biggest downsides of this technique is that it heavily relies on a combinatory categorial grammar (CCG), which must be trained to yield the appropriate results.
Are there other known approaches to such conversion at all, or it is a bad idea?
... it heavily relies on a combinatory categorial grammar (CCG), which must be trained...
There are two broad-coverage CCG parsers for English, which you could use:
Curran & Clark Parser by itself only generates CCG derivations with categories, not with semantics. Boxer works on the parses to generate semantics.
OpenCCG when used with the broad-coverage grammar, MOLOKO can show semantics. But I haven't used this one yet, and can't read their output.
Are there other approaches...
CCG is not the only logic-based grammar. There are others that closer to mathematics, in that, their derivation trees for sentences that look exactly like natural deduction proofs. I think the ACG guys have a working parser. I am not sure about the others like TLG, CVG, etc.
It is also possible to convert natural language into first-order logic using a discourse representation theory. For example, the ACE reasoner is an automated theorem prover that can convert English text into first-order logical predicates.
