Evolutionary theory often describes mutation as random. This does not mean that evolution proceeds without structure, direction, or constraint.
Randomness in this context means that variations do not arise because organisms anticipate future needs. Mutations occur without regard to whether they will later prove advantageous. However, the persistence of those variations depends upon numerous biological constraints.
Organisms must remain viable. Development limits what forms can be produced. Ecological conditions filter which variants persist. Existing organisational structures constrain future possibilities. Natural selection therefore operates on variation within a highly structured biological context.
APS interprets evolution as the long-term transformation of organised persistence. Random variation contributes new possibilities, but viability determines which forms of organisation endure and continue through time.
Randomness supplies variation; biological constraints shape evolutionary outcomes.
Evolution involves contingency, but contingency always operates within biological constraints.