  Hawking radiation and Bekenstein--Hawking entropy are the two robust
predictions of a yet unknown quantum theory of gravity. Any theory which fails
to reproduce these predictions is certainly incorrect. While several approaches
lead to Bekenstein--Hawking entropy, they all lead to different sub-leading
corrections. In this article, we ask a question that is relevant for any
approach: Using simple techniques, can we know whether an approach contains
quantum or semi-classical degrees of freedom? Using naive dimensional analysis,
we show that the semi-classical black-hole entropy has the same dimensional
dependence as the gravity action. Among others, this provides a plausible
explanation for the connection between Einstein's equations and thermodynamic
equation of state, and that the quantum corrections should have a different
scaling behavior.
