Physicist and complexity theorist Theodore Modis analyzed these lists and determined twenty-eight clusters of events, which he calls canonical milestones, by combining identical, similar, and/or related events from different lists.
This process essentially removes the “noise”, the variability between lists, revealing same progression:
The attributes that are growing exponentially in these charts are order and complexity. This acceleration matches our common sense observations. A billion years ago, not much happened over the course of over one million years. But a quarter million years ago epochal events such as the evolution of our species occurred in time frames of just one hundred thousand years.
In technology, if we go back in fifty thousand years, not much happened, nothing happened over a one thousand year period.
But in the recent past, we see new paradigms, such as the World Wide Web, progress from inception to mass adoption (a quarter of the population of advanced countries) within only a decade.
The Singularity is Near, R. Kurzweil, about the Six Epochs. Epoch Four: Technology