At Dinner with Huxley, Spencer mentioned that he had once written a tragedy. Huxley immediately replied that he knew what the plot must be: a beautiful theory gets murdered by a nasty fact. Spencer himself delighted in retelling Huxley’s barb, displaying thereby both his good humor and self-awareness. What he was probably not aware of was that he actually did write a tragedy with Huxley’s plot. In The Principles of Ethics the beautiful theory is that an individual’s conduct is to be judged by how well it furthers the individual’s survival. The nasty fact is that much conduct that furthers survival is morally repugnant both to Spencer and to most civilized people. Like many a good doctor, Spencer operated on the theory in order to save it from the attack of the fact. After the operation, the theory was so disfigured by qualifications and inconsistencies that few people paid attention to it, preferring to remember it as it was in its original pure simplicity.
Diamond, Arthur M. Jr., "Spencer's Tragedy" (1980). Economics Faculty Publications. 34.