All of the entries in this thread made terrific points – I haven’t much to contribute except to say that I think of interesting as very closely related to surprising (another contentious word that often comes up in class). Agreed, that interesting & surprising are subjective evaluations, but unlike purpose (the banishment of which I argued for due to its inherent subjectivity), I see these as more useful. Unlike suppositions of purpose, interesting & surprising are basically Boolean values – they either are or are not (to a person). Therefore if true, they can inform us (as Jesse suggested) about the incompleteness of our knowledge and inspire us (as Paul suggested) to further investigation.