I have been reading the book "The Black Hole War," by L.Susskind, which states:
Temperature is the increase of a system's energy when an entropy bit is added.
Until now I was thinking that, on the contrary, it is the entropy that is increased when energy is added. No matter how you define entropy as hidden information or diffusion of energy or log of microstates or as heat divided by absolute temperature, the arrow of causality is from energy to entropy and not the other way around. I also don't understand why adding of entropy by itself increases energy.
What is the meaning of this definition?