  However, note that the equivocation between relative times and relative numbers, which was relatively harmless in the first section of the 1868 paper, is no longer possible in the interpretation of \(\rho\). The probability \(\rho_{mc}(\vec{p}_1 \mid \vec{q}_1,\ldots,\vec{q}_N) d^3\vec{p}_1\) gives us the relative time that the total system is in a state for which particle 1 has a momentum between \(\vec{p}_1\) and \(\vec{p}_1 + d^3\vec{p}_1\), for given values of all positions. There is no route back to infer that this has anything to do with the relative number of particles with this momentum.