Internal measurement

The internal measurement refers to the quantum measurement realized by the endo-observer. Quantum measurement represents the action of a measuring device on the measured system. When the measuring device is a part of measured system, the measurement proceeds internally in relation to the whole system. This theory was introduced by Koichiro Matsuno and developed by Yukio-Pegio Gunji. They further expanded the original ideas of Robert Rosen and Howard Pattee on the quantum measurement in living systems viewed as natural internal observers that belong to the same scale of the observed objects. According to Matsuno, the internal measurement is accompanied by the redistribution of probabilities that leave them entangled in accordance with the many-worlds interpretation of quantum mechanics by Everett. However, this form of quantum entanglement does not survive in the external measurement in which the mapping to real numbers takes place and the result is revealed in the classical time-space as the Copenhagen interpretation suggests. This means that the internal measurement concept unifies the alternative interpretations of quantum mechanics.