The Nature and Limits of Eliminative Reasoning
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Eliminative reasoning has long been advertised as a method for converting ampliative inference into something closer to demonstrative argument: enumerate the alternatives, exclude all but one, and the survivor inherits something like the security of a deductive conclusion. The familiar worry is that this only displaces the problem onto the construction of the space of alternatives, sharpened by the recurring observation that historically influential eliminative arguments have been undone by alternatives their proponents could not have foreseen. Woodward's (2024) recent treatment of this strategy, based on a notion of truthlikeness about networks of dependency relations, shifts the burden onto whether an exhaustive list of alternative dependency-structures can plausibly be assembled in a given case. Smeenk argues that, at least for fundamental physics, several insights can be dervied from a careful reconstruction of how eliminative inferences actually work in practice. Drawing on the post-1960s testing of general relativity through the parametrized post-Newtonian, post-Friedmannian, and post-Keplerian frameworks and into gravitational-wave astronomy, Smeenk isolates two features of eliminative inferences: (i) locality: eliminative inferences identify a best-fitting dependency-structure within a circumscribed regime, only up to degeneracies (distinct fundamental theories may yield similar results in each regime); (ii) complementarity: tests in distinct regimes, knit together by the structure of a candidate fundamental theory, break degeneracies that no single regime can. Using Woodward's schema as a foil, Smeenk argues that the locality–complementarity pair brings out something that Woodward's framing neglects, namely the cross-regime structure that does most of the epistemic work, and clarifies the limits of eliminative reasoning, which inherits its regime-individuation from the theory itself, and is fragile when there are not sufficient cross-regime links.
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