Ontological uncertainty is uncertainty in reality itself, not uncertainty in its description, knowledge of it, or a chosen model. It means that determinacy need not be complete, predetermined, or exhaustive.
Ontological uncertainty may concern a state, event, process, relationship, boundary, structure, or space of possibilities. What remains uncertain may be not only a particular value within an already specified set of options, but also the set of options itself, the very boundaries of what is possible, or the very structure within which determinacy is supposed to arise.
Ontological uncertainty must therefore not be reduced to a construction in which several options are known in advance and one of them must be realized. Such a construction already presupposes determinacy at a higher level: the options are known, the space of possibilities is given, and the system’s boundaries are established. Ontological uncertainty allows this very level to remain uncertain as well.
Nor does it require uncertainty to exist only in relation to a distinction specified in advance. A distinction may identify a particular form of uncertainty, but this does not mean that uncertainty itself is exhausted by that distinction. Reality need not already be completely divided into a set of parameters that have simply not yet been assigned values.
Ontological uncertainty is therefore connected to the fundamental non-closure of determinacy. Reality need not contain in advance a complete scenario, a final configuration, an exhaustive set of states, or the entire space of what is possible.
The future is one particular case of such uncertainty. Its uncertainty is especially visible because future states, events, and relationships have not yet formed a completed determinacy. But ontological uncertainty is broader than the future and must not be defined through it.
