Lakatos and MacIntyre on Incommensurability and the Rationality of Theory-change :: Science Scientific Philosophy Essays

Lakatos and MacIntyre on Incommensurability and the Rationality of Theory-change ABSTRACT: Imre Lakatos' "methodology of scientific research programs" and Alasdair MacIntyre's "tradition-constituted enquiry" are two sustained attempts to overcome the assumptions of logical empiricism, while saving the appearance that theory-change is rational. The key difference between them is their antithetical stand on the issue of incommensurability between large-scale theories. This divergence generates other areas of disagreement; the most important are the relevance of the historical record and the presence of decision criteria that are common to rival programs. I show that Lakatos' rejection of the incommensurability thesis and dismissal of actual history are motivated by the belief that neither are compatible with the rationality of theory-change. If MacIntyre can deny the necessity of dispensing with the historical record, and show that incommensurability and the consequent absence of shared decision criteria are compatible with rationality in theory-change, then Lakato s' argument will lose its force, and MacIntyre will better honor the intention to take seriously the historicality of science. I argue that MacIntyre can dissolve tensions between incommensurability and rationality in theory-change if he is able, first, to distinguish a sense of the incommensurability thesis that preserves genuine rivalry between theories, and second, to show that the possibility of rationality in theory-change depends not on the presence of common decision criteria, but on the fact that traditions can fail by their own standards. After reconstructing and examining the argument, I conclude that the notion of a tradition's "internal failure" is coherent, but that it leaves crucial questions about the epistemology and ontology of traditions that must be answered if MacIntyre's proposal is to constitute a genuine improvement on Lakatos. Although he is not primarily a philosopher of science, Alasdair MacIntyre has drawn on post-Kuhnian methodological reflection in his formulation of an historicist theory of knowledge (1984a: 271) or what his more recent work terms tradition-constituted inquiry (1988: 354). In many respects, MacIntyres traditions are similar to the research programs described in the work of Imre Lakatos (1977). Both thinkers propose a shift in focus from atomic propositions to some type of holism by making an entire theory, or series of theories, the proper object of evaluation. Each argues that the issues investigated by participants in research traditions are not timeless questions, but are crucially shaped by their own problematics. Without devaluing consistency and logical rigor, each supposes that incoherence of a certain sort is the motor of intellectual progress.