  Putnam's response to this kind of objection is interesting. Very roughly, Putnam suggests that any conditions on intended models which other philosophers might propose—e.g., those mentioned in the last paragraph—should themselves be formalized in first-order terms and treated as new theoretical constraints. When these new constraints are fed back through Putnam's argument, he will once again be able to generate a model which “satisfies” these constraints. So, by simply adopting a particularly flexible reading of the phrase “theoretical constraints,” Putnam ensures that almost any conditions on intended models can simply be folded back into his original argument (Putnam 1980; Putnam 1983,  vii–xii).[48]