I am not talking about straw man arguments in this case because the subject of the paper by Karakostas is not his invention. Specifically, the concept of reality in philosophy is as old as Parmenides. However, deductions based on hidden premises can be problematic, especially when they deal with the nature of reality.
In his paper titled “Realism and Objectivism in Quantum Mechanics“, Karakostas argues that the classical conception of physical reality must be abandoned and replaced by contextual realism:
“It is pointed out, however, that a viable realist interpretation of quantum theory requires the abandonment or radical revision of the classical conception of physical reality and its traditional philosophical presuppositions. It is argued, in this direction, that the conceptualization of the nature of reality, as arising out of our most basic physical theory, calls for a kind of contextual realism.”
Right from the start, two hidden premises are used in the argument:
(1) QM is a true theory of physical reality
(2) There cannot be different conceptions of physical reality
Then, another premise that is used is presented as a principle:
(3) Quantum theory is our most basic physical theory
Based on the above three premises, two hidden and one unfounded, with (1) related to (3) Karakostas develops an elaborate argument in favor of contextual realism. However:
(1) Before one even considers changing the conception of realism, one must justify the assertion that quantum theory is a true theory of physical reality and not just an instrument of science. Otherwise, reality is “fitted” to a theory rather than theory “fitted” to reality, which is the ultimate goal of realism. For example, Lyre (2010) has argued that quantum theory is possibly wrong.
(2) Can we tolerate different conceptions of reality based on different theories? For example, relativity theory makes completely different metaphysical commitments than quantum theory (Esfeld 2009). Can two different conceptions of reality be true at the same time? Karakostas does not answer this question but assumes we cannot.
(3) That quantum theory is our most basic physical theory is a premise used to support the argumentation by Karakostas with no proof. This claim is much too important to be considered an indubitable truth.
After an elaborate argument based on the two hidden assumptions and the principle that quantum theory is our most basic theory, Karakostas states in his concluding remarks:
“A consistent understanding of modern science and its practice requires that we give up the idea that science aims at the description of reality as it truly is in itself…Quantum mechanics reveals that the hunt of a universal perspective for describing physical reality is in vain.”
Obviously, these conclusions do not follow from any of the premises in Karakostas’ argument. There are numerous interpretations of quantum theory and that is an indication that the theory should be viewed in an instrumentalist sense and not as a foundation for an inquiry into the nature of reality or, even worse, for arguing that “we give up the idea that science aims at the description of reality as it truly is in itself”. Because a theory is plagued by interpretational underdetermination that does not mean we should give up aiming at a science that fully describes reality.
FInally Karakostas concludes:
“On the other hand, let the followers of the anti-realist camp avoid condemning any inclination to deal with reality as an idle metaphysical exercise. Physics is not confined to purely operational, descriptive accounts of things;”
After thinking about the above statements for a while I finally understood the confusion in the paper. Realism and anti-realism are about theories and the metaphysical commitments they make, not about reality apart from theories. A reality must ultimately exist and be real in a metaphysical sense. Philosophers and scientists are realists or anti-realists about theories. Theories do not necessarily describe reality and reality may not be sufficiently described by any theory or theories combined. Reality is, what is. Theories come and go, no need to invoke pessimistic meta-induction here. However, when we talk about “Realism and Objectivism in Quantum Mechanics” we have no right to later divert the discussion to “Realism and Objectivism in Science”. Unless we literally believe that quantum theory is the only viable science. I hope the point is clear.