A category mistake, or category error, is a semantic or ontological error by which a property is ascribed to a thing that could not possibly have that property. Semantics is the study of meaning in communication The word derives from Greek σημαντικός ( semantikos) "significant" from In Philosophy, ontology (from the Greek, genitive: of being (part For example, the statement "the business of the book sleeps eternally" is syntactically correct, but it is meaningless or nonsense or, at the very most, metaphorical, because it incorrectly ascribes the property, sleeps eternally, to business, and incorrectly ascribes the property, business, to the token, the book. In Linguistics, syntax (from Ancient Greek grc συν- syn-, "together" and grc τάξις táxis, "arrangement" is the
If all (propositional) mistakes could be said to involve some sort of misascription of properties, then in a sense all mistakes are "category mistakes": putting a thing into a class to which it does not belong. But a "category mistake" in the philosophical colloquial seems to be a very severe form of misascription, involving the endorsement of what is in fact logically impossible. To show that a category mistake has been committed one must typically show that once the phenomenon in question is properly understood, it becomes clear that the claim being made about it could not possibly be true. Thus the mistaken claim that "Most Americans are atheists" is not a category mistake, since it is merely contingently true that most Americans are theists.
The term "category mistake" was introduced by Gilbert Ryle in his book The Concept of Mind (1949) to remove what he argued to be a confusion over the nature of mind born from Cartesian metaphysics. Gilbert Ryle ( 19 August 1900 - 6 October 1976) was a British Philosopher, and a representative of the generation of In his prominent work The Concept of Mind ( 1949) the philosopher Gilbert Ryle described what he saw as the "fundamental mistake" made by Metaphysics is the branch of Philosophy investigating principles of reality transcending those of any particular science Ryle alleged that it was a mistake to treat the mind as an object made of an immaterial substance because predications of substance are not meaningful for a collection of dispositions and capacities. Many philosophers have employed Ryle's idea of a category mistake, but there is no lasting agreement on how to identify category mistakes.