The 'invisible' or 'spiritual' Church is flawed ecclesiology because humans are both physical and spiritual creatures. If a Church is purely 'invisible' or 'spiritual' without any physical element to it at all, then it is irrelevent and inaccessible to humanity because humans are physical creatures as well as spiritual. We demonstrate our spirituality through our physical nature and become spiritual through our physical actions; for humans, the two elements--physical and spiritual--come together and are co-dependent on one another for our salvation. Even C.S. Lewis realized this truth when he referred to humans as 'amphibians'. So logically, if there is an 'invisible/spiritual' Church without a physical element to it, then it is entirely irrelevent to us since we are also physical. Therefore, in order for the Church to be accessible to humans, it must be both physical and spiritual just as we are.