Here is the abstract to Larry Laudan's 1981 A Confutation of Convergent Realism, which according to Wikipedia kicked-off the current notion of the pessimistic meta-induction:
This essay contains a partial exploration of some key concepts associated with the epistemology of realist philosophies of science. It shows that neither reference nor approximate truth will do the explanatory jobs that realists expect of them. Equally, several widely-held realist theses about the nature of inter-theoretic relations and scientific progress are scrutinized and found wanting. Finally, it is argued that the history of science, far from confirming scientific realism, decisively confutes several extant versions of avowedly 'naturalistic' forms of scientific realism.
What is scientific realism? According to the Stanford Encyclopedia of Philosophy:
Scientific realism is a positive epistemic attitude toward the content of our best theories and models, recommending belief in both observable and unobservable aspects of the world described by the sciences.
Specifically, Laudan attacks scientific realism as being unsupported by either reference or approximate truth. I suppose that when realism recommends belief in both observable and unobservable aspects of the world described by the sciences, it is not the observable aspects that Laudan opposes but the unobservable ones.
We will not learn from this whether Laudan is criticizing the truth-value of scientific theories or merely whatever mind-independent reality is contained by scientific theories; instead, we're talking primarily about belief.
Belief in quarks
So, under the pessimistic epistemic attitude, should we believe in quarks? Of course we should believe in quarks! Quarks are observable; it does not matter so much that they are only observable using the right equipment, or that they are only observable indirectly: their known qualities and interactions have been observed and reported to us by various scientists who we have no reason to doubt.
Only a great conspiracy of diverse individuals, unified in resolve, could have presented to the public today's knowledge of quarks without actually making the quark observations. This hypothetical conspiracy fails under any ordinary examination, so belief in quarks is well-warranted.