From the greatest fountain of human knowledge ever constructed: Wikipedia.
(All of science is a very close second.)
Metastable states are inherent features of asynchronous digital systems, and of systems with more than one independent clock domain. In self-timed asynchronous systems, arbiters are designed to allow the system to proceed only after the metastability has resolved, so the metastability is a normal condition, not an error condition. In synchronous systems with asynchronous inputs, synchronizers are designed to make the probability of a synchronization failure acceptably small. Metastable states are avoidable in fully synchronous systems when the input setup and hold time requirements on flip-flops are satisfied.(Source)
And by the Curry correspondence, digital systems correspond to “purely” logical/mathematical constructs, and metastable states are analogous to quantum superpositions.
Therefore, quantum superpositions are a necessary characteristic of any purely mathematical system with multiple distinct functional domains.
This has implications.