The development of human mental ability can be tracked through the progressive crafting of stone tools, Van der Leeuw explained. First we learned to shape an edge---a line---then the surface, then the whole volume of the tool, then the sophisticated sequence required to make a superb spear point. It took 2 million years. But by 300,000 years ago the human brain had developed a sufficiently complex short-term working memory to keep 7 (plus-or-minus 2) considerations in mind at once. We could handle problems of multi-dimensionality.
The brain has not progressed since then, nor has needed to. The skills of innovation moved on from the biological brain to social constructs and modes of communication and information processing. That bootstrapping process continues to this day. The cave paintings show that cognitive agility reached the point of being able to reduce 3 dimensions to a representative 2 dimensions, for instance.
By the Neolithic revolution of 10,000 years ago, we developed the ability to shape voids---the interior of pots, baskets, and houses. Tools could be made by assembling parts instead of just paring down blanks of stone or wood. Problem solving in agriculture began to span time, to be a form of investment.
Towns and then cities became humanity's innovation engine. Symbols recorded in material form---tokens, accounting, and writing---spanned time and space. Unruly cities disciplined themselves with laws and administration. Then empires developed the ability to harvest the bounty of far-flung communities in the form of treasure, and that led to overreach. The Roman Empire was the first to degrade its world at the local climate level, and it collapsed.
Around 1800, in Europe, energy constraints were finally conquered by the harvesting of fossil fuels. Humans only need 100 watts to survive, but every human now commands 10,000 watts. With that leverage we built a global civilization. The innovative power of urbanity has multiplied yet further with the coming of the Internet.
But we have become "disturbance dependent." As our cities and density of communications grow, they create ever more difficult problems, for which we have to innovate ever more sophisticated solutions. Technology is "the biggest Ponzi scheme of all."
As we become ever more adept at solving short-term problems, we shift the risk to long-term problems---such as climate change---which do not match the skills we have developed and know how to reward. We are headed into a trap of our own devising. To get out of it, if we can, will require a "battle with ourselves" to wholly redefine our social structures and institutions to master the long term.-- by Stewart Brand