Expert system (the dumb) has these limitations: common sense, inspiration or intuition and flexibility to apply in the semi-relevant field. Experts (the sensible) decide based on their overall view of the occurred problem, but expert system has not enough information. Experts know their lack of knowledge and the limits of their information in dealing with new problems, but expert systems have narrow knowledge domain and just work when they are developed for specific or very specific problems. (source)
Unfortunately, off-the-shelf education can often make human just an expert system. The actual learning experiences: knowing what works and what doesn't, how and why, conceptualizing concepts across different phenomena; that make human an actual expert.