ABSTRACT
A very interesting property of the entropy is that it tends to increase as things are jumbled up, that is, with disorder. Just as scientists began to think that no more surprises were to be had from the entropy concept and the second law, the existence of black holes became an interesting speculation. Thus when a gas expands into a neighbouring, previously empty, container its entropy goes up because, unable to give a full atomic description, one uses a coarser, more thermodynamic, account. The increase of entropy provides one of the key physical indicators of the progress of time. As physicists might expect from metaphors, the use of the entropy concept is only suggestive and often superficial. The entropy concept fits into the scheme not only because of its wide use in science, but also because it is a metaphor in the humanities. It is thus a vehicle which enables to appreciate the unity of knowledge.
