  However, a form of potentialism about the hierarchy of sets continues to enjoy considerable support, especially in connection with the iterative conception of sets (Parsons 1977, Jané 2010, Linnebo 2013, Studd 2013). No matter how many sets have been formed, it is possible to form even more. If true, this would mean that sets have a potential form of existence which distinguishes them sharply from ordinary physical objects. 