The need for a concise definition for life has been accentuated by recent interest in computer based Artificial Life (A-Life). We attempt to apply conventional approaches to defining life in the domain of computer programs. Chemical autopoiesis in the physical space is accepted as necessary and sufficient for life. This forces us to make a distinction between physical and virtual entities. From this, we re-formulate the goal of creating algorithmic life, making allowances for the limitations of non-physical, virtual environments. We examine a number of potential 'virtual organisms' for possession of the necessary characteristics to determine in what sense they are living things. We are lead to conclude that non-physical entities, hence computer programs, cannot be living things. Some computer programs do however share characteristics with real life, depending on the level at which they are described.
Artificial Life, Autopoiesis, Virtual Environments, Virtual Life