 It has been argued that there is one kind of complex expression that generally belongs to the periphery, and that is reifying NPs of the sort the number eight, the property of being happy, the proposition that it is raining, or the truth value true (Moltmann 2020c). It is a general observation that philosophers usually stay away from reifying NPs when drawing on natural language for motivating an ontological category. For example, Frege (1884) did not motivate numbers as objects by appealing to the construction the number eight in natural language, and he did not motivate truth values as objects by appealing to the truth value true. Rather he used expressions from the core like the number of planets and eight when arguing for numbers being objects, and his motivations for considering truth values to be objects did not come from particular natural language sentences at all. Likewise, Hale (1987) argued for properties being objects not on the basis of terms like the property of mercy, but rather simple terms like mercy from the core of language. Finally, Link (1979) motivated mereological sums being part of the ontology of language not on the basis of terms like the sum of the students from the periphery of language, but rather simple definite plurals like the students. The semantics of reifying terms itself appears to be associated with abstraction involving the introduction of an entity on the basis of a nonreferential (use of) an expression (Moltmann 2013, chap. 6). If such an operation of object introduction (a form of derivative acceptance) defines the content of reifying terms  (§3.1.3),  their classification as part of the periphery may become plausible.