Reification (also known as concretism, hypostatization, or the fallacy of misplaced concreteness) is a fallacy of ambiguity, when an abstraction (abstract belief or hypothetical construct) is treated as if it were a concrete real event or physical entity.[1][2] In other words, it is the error of treating something that is not concrete, such as an idea, as a concrete thing. A common case of reification is the confusion of a model with reality: "the map is not the territory".
Reification is part of normal usage of natural language, as well as of literature, where a reified abstraction is intended as a figure of speech, and actually understood as such. But the use of reification in logical reasoning or rhetoric is misleading and usually regarded as a fallacy.[3]
A potential consequence of reification is exemplified by Goodhart's law, where changes in the measurement of a phenomenon are mistaken for changes to the phenomenon itself.
Whether a phrase commits the fallacy depends crucially upon whether the use of the inaccurate phrase is inappropriate in the situation. In a poem, it is appropriate and very common to reify nature, hope, fear, forgetfulness, and so forth, that is, to treat them as if they were objects or beings with intentions. In any scientific claim, it is inappropriate.