in digital computing, we also have the "high" and "low" phases in circuits, created by the oscillator. With this, we can distinguish each bit and process the stream.
Only if the stream plays by the rules, and doesn't do something unfair like, say, undervolting the signal line in order to push the receiving circuit out of its operating envelope.
Every system we design makes assumptions about the system it works on top of. If those assumptions are violated, then invariants of the system are no longer guaranteed.
