And yet, when you ask what is the greatest thing or idea ever created by humans, the reply is not usually any of the Wonders of the World, or the Mona Lisa, or

And yet, when you ask what is the greatest thing or idea ever created by humans, the reply is not usually any of the Wonders of the World, or the Mona Lisa, or a chess program. It is usually language or writing or something which was similarly a sea change in the development of humanity as we know it today. My argument is that these are the better criteria for "greatness" than the relative ease of performing a specific task, though that task may implicitly represent the great thing. E.g., one may call the printing press the greatest invention ever, not because it was great but because it ushered in a new age.