Energy and entropy are quite different though; energy certainly is a property of the system itself. Temperature, interestingly, is also in our heads. It isn't

Energy and entropy are quite different though; energy certainly is a property of the system itself. Temperature, interestingly, is also in our heads. It isn't actually a measure of average energy, but actually is defined as a function of energy and entropy. (Entropy comes first and temperature is defined in terms of it, not the other way around). T = dQ/dS You can create systems in real life with infinite temperature, or even with negative temperature, but of course they certainly don't have infinite energy. One way to do so is to pump a system into having a population inversion, such that its entropy decreases as its energy increases, because the number of possible high energy microstates is small. In general, only one microstate is ever "available" for a system to evolve into, which is the one that its current microstate will evolve into in accordance with the laws of physics. The trouble is that we don't know its current microstate, so we don't know its future microstate, so it seems to us that there are many available microstates, but that's all due to our own ignorance having only conducted summary statistical measurements and isn't an intrinsic property of the system.