Although we cannot measure the total enthalpy, H, the good news is that we really do not need to know its value. We care only about what our system could do for us right here at a particular place on this planet. All we care about is by how much the enthalpy changes, because it is only this enthalpy change that is available to us. In other words, we really have no need for the absolute values of Hfinal and Hinitial. All we need is the difference, △H, and this is something we can measure.