Organisational systems are as subject to the exigencies of thermodynamics as are any other material systems. What often misdirects us in successfully understanding or defining the ontological properties (existence) of organisational systems is the mischievous dual-nature of organisations as logical and symbolic (mental) concepts and in some sense also as materially-extended constellations of entities (persons), objects (physical components) and relationships (actions, processes). In this sense of organisational entities possessing potentially irreducible dualism, we find Idealism and Materialism percolating back up from (relatively) nebulous consequences in philosophical argument back into the concrete real-world problems of how we might best engage with effectively defining, designing and optimising organisational systems.