Putnam's argument against metaphysical realism

In Reason, Truth and History, Putnam argues against metaphysical realism and thus proposes to substitute it with a new ontological conception, the so-called "internal realism." In my opinion, his main arguments against metaphysical realism are the following: on the one hand, the model-theoretic argument; on the other, an argument based on the non existence of a unique true description of the world that might be named "argument from perspectivism." In this paper, I intend to defend the thesis that both arguments are affected by the same kind of problem: namely, they wrongly assume metaphysical realism to necessarily involve certain doctrines, more specifically, the correspondence theory of truth and the thesis of the existence of a unique true description of the world. I try to argue that, Putnam's opinion notwithstanding, metaphysical realism is conceptually independent of both doctrines; I then conclude that Putnam's arguments against it, mainly aimed at them, have failed to achieve their purpose.