For \\(f_\ast(\\{\text{there is a living cat in your room}\\})\\), I get the set of all thermometer readings which are *only* possible if there is a live cat in the room. (This is interpreting the state set {there is a living cat in your room} not as a singleton but as the set of all room states in which the room contains a living cat.) I imagine for most interpretations of the function \\(f\\) this set is empty.

If we think of \\(f_!\\) and \\(f_\ast\\) as best approximations to an imaginary "inverse" of \\(f^\ast\\), then we're trying to find the best approximation from above or below to some imaginary set of temperature readings that correspond exactly to the room states containing a live cat. The "liberal" left adjoint \\(f_!\\) generously throws in all the temperatures for which *some* corresponding room state contains a live cat, while the "conservative" right adjoint \\(f_\ast\\) cautiously only allows the temperatures for which *all* corresponding room states contain a live cat.