When I started with Yuval Noah Harari’s Homo Deus, I expected to jog along with a fun and clever assessment of human history and its near future as a cyborg-like merger of human and computer.
But I had trouble early on.
Dr. Harari repeatedly throws out a flurry of proclamations, often sweeping claims as arguments, then follows them with his intended conclusion, sometimes sweeping, head scratching and not always adding up. Then there are terms about which he seems to have a slightly skewed understanding.
I collided with his usage of “Cognitive Revolution” almost from the start. According to Harari, the "Cognitive Revolution" occurred 70,000 years ago causing the homo sapiens mind to shift, turning the species from “an insignificant African ape” into modern humans as “ruler of the world.” I looked for supportive context or attribution in the text, but it wasn’t there. Nor was there any footnote for the claim.
I knew the term from a different context entirely. I Googled to be sure. "Cognitive Revolution" was the name of a 1950's multidisciplinary movement (now cognitive science) studying the mind and its workings. Noam Chomsky was one of the pioneers of the field.
I could find no reference about Harari’s usage until I added “Harari” or “Homo Deus” to the search terms. Then I got hits on “Homo Deus” and "Sapiens" (his previous book, where “The Cognitive Revolution” is the title of the very first section of “Sapiens”). This is where Harari sets out his theory of sapiens cognition as a basis for the next brain change.
In Homo Deus Harari states, “this … revolution resulted from a few small changes in the Sapiens DNA and a slight rewiring of the Sapiens brains. … another rewiring of our brain will suffice to launch a second cognitive revolution.” Using, he continues, “… genetic engineering, nanotechnology and brain-computer interfaces.”
I looked for further source information on Harari’s claim. The best I came up with was an arguable theory about a population bottleneck some 70,000 to 60,000 years ago caused by an extinction when a volcano in Indonesia, Toba, erupted 74,000 years ago.
The theory, now mostly refuted, was that Toba’s eruption lowered temperatures around the world wiping out many species, dropping the human population drastically.
Recent studies looking at sediment cores around the world for 100 years before and 200 years after Toba erupted, showed no signs of species die offs. Any effect was mild enough that it did not show up in the sediment layers.
Depending on the source, Homo Sapiens is believed to have emerged about 300,000 years ago (or even 400,000 years ago) and was in Europe at least by 200,000 years ago. A skull found in Greece was just dated to 210,000 years ago. Throw in speculation about “big chills” at 195,000 and 150,000 years ago and a possibility that humans dropped to as little as 40 people, or 600 people or a few thousand people or were always not that plentiful or came from a small group which left Africa at some time or other.
In East Asia, human remains in China have been dated to 100,000 years ago. In Japan, there is evidence of watercraft 84,000 years ago, in Honshu. Those early East-Asia dates argue against Harari’s theory.
Harari doesn’t tell us where he got the term. Did he hear it somewhere and misunderstand it, making assumptions? Could he have stumbled on “Cognitive Revolution” on his own? Fact checking at the publisher should have revealed this term in prior use. Nor could I find any reference by Harari referencing the 1950’s movement of that name in either “Sapiens” or “Homo Deus” or elsewhere, including numerous videos.
The same doubt goes for assumptions about brain changes 70,000 years ago. What we have of skulls doesn’t show a change in brain dimensions. Harari uses the brain-change at 70,000 years ago version of pre-history to bolster the viability of humans making the next change in our species.
There is very little we can say with certainty about our origins. That makes doubtful Harari’s prediction that we are about to re-design our own species by attaching computing devices to our brains.
A nice, brief synopsis of Homo Sapiens:
Revisiting and refuting a theory about an extinction at 74,000 years ago:
Concept of Behavioral Modernity