To think well is to impose discipline and restraint on our thinking-by means of intellectual standards - in order to raise our thinking to a level of "perfection" or quality that is not natural or likely in undisciplined, spontaneous thought. The dimension of critical thinking least understood is that of "intellectual standards." Most teachers were not taught how to assess thinking through standards; indeed, often the thinking of teachers themselves is very "undisciplined" and reflects a lack of internalized intellectual standards.