 Historically the problem arose in a wonderful series of debates and arguments between the great physicist Ludwig Boltzmann and some of his contemporaries, notably, Johann Loschmidt, Ernst Zermelo and Edward Culverwell. Boltzmann was one of the founders and most influential developers of the field of statistical mechanics, as well as (later in life) a philosopher. While seeking a mechanical underpinning of the Second Law, he discovered a particularly ingenious explanation for why systems tend toward equilibrium.