The simplest kind of elaboration is the addition of new formulas. Next comes changing the values of parameters. Adding new arguments to functions and predicates represents more of a change. However, elaborations not expressible as additions to the object language representation may be treatable as additions at a meta-level expression of the facts. Elaboration tolerance requires nonmonotonic reasoning. The elaborations that are tolerated depend on what aspects of the phenomenon are treated nonmonotonically. Representing contexts as objects in a logical formalism that can express relations among contexts should also help. We use the missionaries and cannibals problem and about 20 variants as our Drosophila in studying elaboration tolerance in logical AI.

The paper is http://www-formal.stanford.edu/jmc/elaboration.html. A related paper by Vladimir Lifschitz is "Missionaries and cannibals in the causal calculator" http://www.cs.utexas.edu/users/vl/mypapers/mc.ps.