
The quantum state cannot be looked at directly; observation is destruction. So the system asks only indirect questions, checking parity without ever reading the answer itself.
A continuous wave of decoherence, when interrogated this way, is forced to snap into discrete, binary syndromes. Only the shadow of the error is measured, and from that shadow alone, the error is undone.
This is the logic of quantum stabilizer codes: truth is protected by asking questions the state cannot lie to.