[quoting Halff, 20 Mar 97] I can't imagine anyone accusing Kurt of not appreciating complexity. What does distinguish his work from the mainstream of educational research is that he also appreciates the need for precision. I suppose that if one feels that precise thinking precludes an appreciation for complexity, one might think that Van Lehn could not possibly appreciate complexity.
Sorry if I have misconstrued this. I was simply making assumptions based on a few lines quoted by Clark Quinn [20 Mar 97] which appeared to me to be very similar to the algorithms much beloved of 1960s educational theorists. If I've derogated Kurt Van Lehn I apologize and if someone sends me a reference to his work I'll be happy to read it.