The Case of Early Copernicanism: Epistemic Luck vs. Predictivist Vindication

From Copernicus himself up to Kepler and Galilei, Copernicans have been “right for the wrong reasons” (Finocchiaro, Defending Copernicus and Galileo: Critical Reasoning in the Two Affairs. Springer, Dordrecht, 2010), because there were no epistemically compelling reasons objectively favoring the Copernican position at that stage—a good deal of research in the history and philosophy of science has converged on this claim. The situation of early Copernicans would then be regarded as one of “epistemic luck”. Lakatos and Zahar (Why did Copernicus’s research programme supersede Ptolemy’s? University of California Press, 1975) have featured in one relatively rare contemporary episode of sustained opposition to the epistemic luck thesis about early Copernicanism. Although known and appreciated in certain philosophical circles, it is fair to say that Lakatos and Zahar’s predictivist vindication has remained quite unsuccessful. The goal of this paper is to revive it in updated form. My analysis will support two general claims. First and foremost, previous limitations of a predictivist account of the Copernican controversy can be amended to counter the epistemic luck thesis. And second, consideration of the vindication thesis highlights certain important but neglected elements of the historical narrative.