A category mistake arises when things or facts of one kind are presented as if they belonged to another. According to Ryle, "the logical type or category to which a concept belongs is the set of ways in which it is logically legitimate to operate with it." (Ryle, lx). For example, a friend is invited to visit my house, after being shown the garden, dining room, bedroom, balcony and family members, he will continue to ask me “where is your house?” . This would be a category mistake because the house is not an entity above people and goods, but is the people and goods. Another example would be if someone said that their sadness is long, but sadness is an emotion that cannot be said to be long. Two citizens who pay taxes belong to the same category but the average taxpayer does not. As long as citizens continue to misunderstand the average taxpayer, they will think of him as a particularly additional taxpayer. Ryle points out that mind-body dualism is an illusion produced by this kind of abuse of the ordinary