What is the definition of mass tourism? There are said to be two issues related to the problem of mass tourism today: one is the impact on the natural and social environments due to the huge number of tourists, the other is the loss of each tourist's individual personality within mass tourism. This paper surveys the main characteristics of discussions so far and argues that mass tourism should basically be grasped as an integration of two sets of inconsistencies, best expressed as homologation relationships in the shape of Greimas' square.