Schein has proposed that these categories exist within corporate culture on three levels in what is conceptualised as his iceberg model of culture - first there is the surface level of Artefacts and Etiquette (visible elements such as language, form of greeting, clothing, physical layout), the middle level is the espoused values which are not immediately visible but drive a consistent pattern of behaviours ad actions throughout the organisation. There is the deep level called the basic underlying assumptions which are the culture's unconscious, taken for granted values and beliefs, their core ethics and morals which guide judgements that the group holds about what is right or wrong, fair or unfair