The partition function for a driven harmonic oscillator is questioned due to the system's non-equilibrium state caused by the driving force. It is generally understood that the partition function is well-defined only at equilibrium, which complicates its calculation for driven systems. Some participants express skepticism about the feasibility of applying traditional partition function methods in this context. The discussion highlights the need for alternative approaches or modifications to account for the energy input from the driving force. Overall, the consensus leans towards the difficulty of defining a partition function for non-equilibrium systems like a driven harmonic oscillator.