  Stellar ages are key for determining the formation history of the Milky Way,
but are difficult to measure precisely. Furthermore, methods that use chemical
abundances to infer ages may entangle the intrinsic evolution of stars with the
chemodynamical evolution of the Galaxy. In this paper, we present a framework
for making probabilistic predictions of stellar ages, and then quantify the
contribution of both stellar evolution and Galactic chemical evolution to those
predictions using SHAP values. We apply this interpretable prediction framework
to both a simulated Milky Way sample containing stars in a variety of
evolutionary stages and an APOGEE-mocked sample of red clump stars. We find
that in the former case, stellar evolution is the dominant driver for age
estimates, while in the latter case, the more restricted evolutionary
information causes the model to proxy ages through the chemical evolution
model. We show that as a result of the use of non-intrinsic Galactic chemical
information, trends estimated with the predicted ages, such as the
age-metallicity relation, can deviate from the truth.
