  In 1939, von Neumann argued for the equivalence of the thermodynamic entropy
and $-\text{Tr}\rho\ln\rho$, since known as the von Neumann entropy. Hemmo and
Shenker (2006) recently challenged this argument by pointing out an alleged
discrepancy between the two entropies in the single particle case, concluding
that they must be distinct. In this article, their argument is shown to be
problematic as it a) allows for a violation of the second law of thermodynamics
and b) is based on an incorrect calculation of the von Neumann entropy.
