Of course idealizations are incommensurable!
Kuhnian treatment of theory comparison has engendered various worries about scientific rationality. The problems are real but, I suggest, their apparent intractability is an artifact of thinking of science as being in the exact truth business. Instead, following Cartwright, Giere, and others, think of science as being in the business of systematically developing idealized models that are always limited in scope and never completely accurate. Bear in mind that what model is appropriate depends sensitively on interests and other contextual features so that evaluation always needs to be relativized both to human interests and to the limits of human capacities. Consequently, evaluation is relative to our predictive, explanatory, and other interests, both practical and intellectual. Absent the fixed but humanly unattainable objective of truth, such subsidiary interests can appropriately vary, often as a matter of personal or collective values. Recognizing that the best that is humanly accessible are alternative idealizations, that we expect the phenomena to be usefully approached through a variety of theoretizations suddenly looks not only natural but an asset.
Soler Léna, Sankey Howard, Hoyningen-Huene Paul (2008) Rethinking scientific change and theory comparison: stabilities, ruptures, incommensurabilities?. Dordrecht, Springer.
Teller Paul (2008) „Of course idealizations are incommensurable!“, In: L. Soler, H. Sankey & P. Hoyningen-Huene (eds.), Rethinking scientific change and theory comparison, Dordrecht, Springer, 247–264.