That might seem to put paid to the threat of strong underdetermination: if we can’t separate out the observable and unobservable parts of a theory, we can’t even make sense of the idea of distinct theories with the same observational consequences. At worst, we might have a case of weak underdetermination, like the dark matter/MOND case, where evidence does bear on the debate but at present it does so inconclusively. Nonetheless, there are still ways in which strong underdetermination might occur.
Underdetermination
