  Zurek (1986) is the most prominent example of attempts to relate quantum measurement to the Szilard engine. Zurek suggested that a molecule being in a superposition of being on either side of the partition, in the Szilard engine, is not subjective uncertainty as to which side the molecule is located. Instead it is an objective fact that the quantum state occupies both sides. Even with the partition present, the molecule occupies the entire box. Until a measurement is performed, collapsing the quantum state to one side or the other, work cannot be extracted. Zurek still regarded the resetting operation as the source of compensating entropy increase. This is justified as necessary on the basis that the demon, having performed the measurement and extracted the work, is now in a statistical mixture of having observed each of the possible outcomes. For the cost of resetting the demon, Zurek appealed directly to Landauer's principle.