The loss of individuality from classical to quantum physics

A. Rossi

pp. 417-426

in: Claudio Garola, Arcangelo Rossi (eds), The foundations of quantum mechanics, Berlin, Springer, 1995

Abstract

Quantum Mechanics doesn't confine itself, as Relativity Theory, to making some properties of bodies variable and dependent on their state of motion, but it also questions the concept itself of individual object. At variance with Classical Statistical Mechanics, which admits an indistinguishability in fact but not in principle among individual objects, Quantum Mechanics does not distinguish at all among apparently identical atomic particles. However, though the different quantum statistics introduce different correlations among atomic objects, they do not automatically verify specific theoretical models of those objects, such as their supposed loss of identity. This conclusion contradicts the opinion of E. Fermi, the author, with P. A. M. Dirac, of the second quantum statistics, who did not want to question this point seriously in the philosophically disengaged Italian scientific milieu of his time.