An excerpt from a letter found in Beatrice Webb's book, My Apprenticeship, on page 90n–91n.

"I don't know whether he [Herbert Spencer] was ever made to realise the implications of the second law of thermodynamics; if so, he might well be upset. The law says that everything tends to uniformity and a dead level, diminishing (not increasing) heterogeneity. Energy is only useful when unevenly concentrated, and the law says that it tends to become evenly diffused. This law used to worry optimists about the time when Spencer was old. On the other hand, his optimism was always groundless, so his pessimism may have been equally so; perhaps the cause of both was physiological".