  What are the metaphysical implications of quantum physics? One way of approaching this question is to consider the impact of the theory on our understanding of objects as individuals with well defined identity conditions. According to the ‘Received View’, which was elaborated as the quantum revolution was taking place, quantum theory implies that the fundamental particles of physics cannot be regarded as individual objects in this sense. Such a view has motivated the development of non-standard formal systems which are appropriate for representing non-individual objects. However, it has also been argued that quantum physics is in fact compatible with a metaphysics of individual objects, but that such objects are indistinguishable in a sense which leads to the violation of Leibniz’s famous Principle of the Identity of Indiscernibles. This last claim has also been contested opening up a further way of understanding the individuality of quantum entities. As a result, we are faced with a form of underdetermination of the relevant metaphysics by the physics, in which we have, on the one hand, quantum objects-as-individuals and, on the other, quantum objects-as-non-individuals. It has been argued that this underdetermination of such fundamental metaphysical ‘packages’ has important implications for the realism-antirealism debate. 