“Definitions, like questions and metaphors, are instruments for thinking. Their authority rests entirely on their usefulness, not their correctness. We use definitions in order to delineate problems we wish to investigate, or to further interests we wish to promote. In other words, we invent definitions and discard them as suits our purposes.”

Language Education in a Knowledge Context (1980)
Context: Definitions, like questions and metaphors, are instruments for thinking. Their authority rests entirely on their usefulness, not their correctness. We use definitions in order to delineate problems we wish to investigate, or to further interests we wish to promote. In other words, we invent definitions and discard them as suits our purposes. And yet, one gets the impression that... God has provided us with definitions from which we depart at the risk of losing our immortal souls. This is the belief that I have elsewhere called "definition tyranny," which may be defined... as the process of accepting without criticism someone else's definition of a word or a problem or a situation. I can think of no better method of freeing students from this obstruction of the mind than to provide them with alternative definitions of every concept and term with which they must deal in a subject. Whether it be "molecule," "fact," "law," "art," "wealth," "gene," or whatever, it is essential that students understand that definitions are hypotheses, and that embedded in them is a particular philosophical, sociological, or epistemological point of view.