Entropy is defined in physics as a mathematical expression of the degree to which the energy of a thermodynamic system is so distributed as to be unavailable for conversion into work. In more general metaphorical terms, entropy may be seen as the irreversible tendency of a system, including the universe, toward increasing disorder and inertness. That is to say, things have a way of getting worse and worse all the time, until in the end they get so bad that we lack even the means of knowing how bad they really are.

//Robert Silverberg, Dying Inside