According to classical niche theory, species in natural communities coexist because every species is the best competitor in its own niche. Neutral theories of biodiversity, on the other hand, suggest that natural communities are largely open, non-equilibrium assemblages of functionally equivalent species. Here I examine some aspects of the so-called neutral-niche debate, particularly in relation to the nature of stochasticity in neutral theory. The use of stochasticity in neutral theory also embodies a philosophically different approach to theory and > model development whose broader implications are tentatively discussed..