category mistake

A category mistake in philosophy occurs when a term or concept is used in a way that is nonsensical because it belongs to a different logical category. This means that if you substitute a term from one category into a statement meant for another, the resulting assertion becomes meaningless.1

For example, Aristotle used categories to classify predicates, distinguishing between types like substances, quantities, and relations. He argued that confusing these categories, such as mistaking a change in relation (like height) for a change in substance (like being human), leads to nonsensical statements. This concept was further developed by philosophers like Immanuel Kant and Bertrand Russell, with Gilbert Ryle famously coining the term "category-mistake" to describe such philosophical errors, particularly in linguistic philosophy.1