From wikipedia: "The second law is an empirically validated postulate of thermodynamics" [1] And "Empirical evidence (also empirical data, sense experience,

From wikipedia: "The second law is an empirically validated postulate of thermodynamics" [1] And "Empirical evidence (also empirical data, sense experience, empirical knowledge, or the a posteriori) is a source of knowledge acquired by means of observation" [2] So, it is a law by observation after all. [1] http://en.wikipedia.org/wiki/Second_law_of_thermodynamics http://en.wikipedia.org/wiki/Second_law_of_thermodynamics [2] http://en.wikipedia.org/wiki/Empirical_evidence http://en.wikipedia.org/wiki/Empirical_evidence