Formal logic requires translating English sentences into a language that lacks the ambiguities and subtleties of natural languages. If I said to you, 'Every five minutes, a man from the L.A. Times has been calling,' you would immediately interpret the sentence differently than you interpreted the one about the man being mugged. But when students try to learn an unambiguous language, they have problems because they lack this understanding of English ambiguities. Grade Grinder uses sophisticated computer algorithms to check such things as the logical equivalence of the student's sentence with expected answers, and its truth or falsity in a large number of contexts. Grade Grinder most likely never will replace a human instructor, Barker-Plummer and Etchemendy say, but it can free instructors and students of their most tedious teaching and learning tasks.
Instructors still grade about half of the homework.
About a dozen of the professors who used Language Proof and Logic this year were polled by e-mail for this article. All who responded said the grading service made teaching logic easier on them and learning it easier on their students. The automated grader worked flawlessly and freed my TA to help with substantive issues in logic, rather than mechanical checking of proofs. I believe this is the future. It's the start of tutoring agents that handle parts of teaching traditionally done by humans.