Recent debate has questioned the validity of Zen as a school of Buddhism, claiming that the characteristic justification of apparently immoral acts by 'enlightened' individuals cannot be reconciled with the Buddhist eight-fold path, which emphasises 'right' actions and states of mind. To simply dismiss Zen as deviant, however, ignores the ramifications of this problem for Buddhists more widely and overlooks parallels with the contemporary problem of nihilism. This thesis investigates the philosophical ground ofthe 'Zen moral problem' in 'emptiness' (sDnyato), through the construction of a metaphysical framework based upon the related Mahayana Buddhist principle: 'interdependence' (pratJtyasamutpoda). In order to critique the validity of Zen as philosophy, I am guided by the goal of the Buddhist soteriological project; the promise of enlightenment in order to overcome the experience of suffering. If a framework built up from base principles of Zen thought is capable of explaining and maintaining the Buddhist goal, then we must still determine how the moral problem arises. It is important to note that this thesis does not represent a Buddhist position, in a textual sense; instead it is a philosophical examination of Buddhist principles - addressing the problems that motivated specific historical positions. Rather than an analysis of these historical positions as such, the current work takes them as responses to a common concern, and makes use of them as critical examples. To this end the metaphysical framework developed here is used to analyse those foundations in contemporary thought which give rise to the moral problem.