 An epistemological reductionist concerning a science or theory S holds that in fact, we are (or at some point will be) able to reduce S to a more fundamental science. It is a thesis about what we can epistemically achieve. The ontological reductionist is, in this respect, more modest: She just holds that in fact, there is just one sort of objects and properties out there in the world; however, due to our cognitive limitations, we might never be able to actually carry out all the reductions that would be appropriate given the actual ontological structure of our world (Scerri &amp; McIntyre 1997; Esfeld &amp; Sachse 2010).