Teru Miyake's project focused on the problem of underdetermination, particularly in cases where the object of investigation is inaccessible to scientists in some way. Epistemological debates among planetary astronomers in the sixteenth and seventeenth centuries, and debates among philosophers with regard to microphysics in the twentieth century are cases in point. These cases have traditionally been considered in terms of the notion of observational underdetermination: situations where more than one hypothesis is consistent with a particular set of observations. Teru Miyake took an entirely new approach to the epistemology of inaccessible systems, and thereby provided a new perspective from which to consider the philosophical problem of underdetermination, and related problems such as the role of a priori principles in science. Teru Miyake argued that both underdetermination and the role of a priori principles are deeply related to issues that scientists face when attempting to carry out indirect measurement. He examined both historical and contemporary cases of indirect measurement with an emphasis on how certain epistemological problems of indirect measurement, particularly with regard to inaccessible, antecedently unfamiliar systems, relate to underdetermination and the role of a priori principles in science.
An important part of the project was three case studies of indirect measurement on inaccessible systems, on planetary astronomy during the period from Copernicus to Newton, on the study of the interior of the Earth by seismologists in the twentieth century, and on contemporary neuroimaging.