Mutations that occur in the absence of selection have often been cited as evidence that mutations are philosophically random— that is, that they do not follow a predetermined pattern but occur haphazardly. Mutation in absence of selection, however, may be a part of an adaptation process, specifically engineered for maintaining variability in organisms as a hedge against future environmental changes. A statistically random distribution of a constrained set of semi-specific (i.e. nonphilosophically random) mutations in populations would enable them to preserve a fairly constant percentage of mutants, which would foster survival in adverse conditions.