The human brain is in some ways an even more extreme example of a process that is far more creative than destructive. We effectively have three evolutionary versions of brains in our heads. Our brains are rather like a city that has existed since ancient times. In Cambridge, for instance, the historic center is squashed inside a fertile bend in the river Cam. This is the core of the city. Here there used to be a castle on a small hill, originally built by William the Conqueror in the eleventh century. The oldest parts of the university, along with old churches and so on, are still there. Over the centuries, housing, university colleges, and research departments have sprung up around this central district. And now, around this second band of somewhat old structures, there are the outer suburbs, with modern housing along with large technology and business parks. Although an unromantic person might be tempted to replace the oldest buildings of the city and the narrow winding roads of the core area with efficient modern streets and buildings, all these ancient places still serve some purpose today. The expense of such renovations simply wouldn’t be worth the trouble.
An interesting comparison. However, even in revered ancient cities, changes have been made in the core, whether it is the rise of some modern buildings or the widening of streets to accommodate cars or the burrowing underground for subways or an updated infrastructure for features like sewers and fiber optic cables.