Mesofacts: slowly changing facts

Chess players are often rated according to a methodology developed by Arpad Elo, which is implemented by a number of organizations, including FIDE. According to this system, the ratings of the greatest players has increased over time, making this a mesofact. However, there are many who contend that this is simply a symptom of ratings inflation, and is not necessarily due to a true increase in the skill of the players. This is discussed in detail here.