The Historical Objections to Realism
The most severe objection to realism, beside empirical underdetermination, is that in the history of science most theories sooner or later have been found to be false, and none that is still accepted is older than 100 years or so.
This is the premise of the so called “pessimistic meta-induction” (PMI) (Putnam 1978a: 25):(PMI1) all past theories were completely false, even the successful ones;
(PMI2) there is no radical epistemic or methodological difference between past and present theories; therefore
(PMI3) most likely also current and future theories are and will be completely false; therefore
(PMI4) unobservable entities cannot be known.
(PMI2) is often left implicit, although it is crucial to the argument. (PMI1) also works as a premise to Laudan’s (1981) refutation of the NMA, called by Lyons (2002) the “meta-modus tollens” (MMT):
(MMT1) past successful theories were completely false; therefore
(MMT2) truth is not the only explanation of success; therefore
(MMT3) the NMA is flawed.
Even restricting the notion of success to novel predictions will not save the NMA from the MMT: as pointed out by Lyons (2002), many ancient false theories made important novel predictions.
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