Harari dissects human history into four parts: the Cognitive Revolution, the Agrarian Revolution, the Political Revolution, and the Scientific Revolution.
During the Cognitive Revolution, Homo sapiens began to exhibit nuances of mental activity. They started to reason and have more control over their actions. This advancement allowed humanity to come together in large numbers and consolidate. Their rapid activity caused the extinction of many species, including the Neanderthals. The power of imagination gave birth to civilization, and without that ability, humanity might have gone extinct.
In the Agrarian Revolution, Homo sapiens began to set aside land for cultivating crops. This led to high food production and rapid population growth. However, the change in diet and movement greatly reduced the quality of life. Humans are forced to live in one location for a long period, waiting to harvest their crops. This exposed them to warring factions, diseases, and natural calamities.
The Political Revolution saw the consolidation of power through the formation of political banners and the birth of nations. As humans became more intelligent, the desire to rule over the world became more apparent. They created new avenues of control, like religion, monetary values, boundaries, and political ideologies. These systems of control were oppressive. Humans would use violence to dominate one another. Power became the ultimate currency, and they would use whatever means to get it. This obsession eventually led to world wars that would kill millions of people.
The Scientific Revolution, which is by far the most advanced, introduced humanity to great medical and technological advancements. Humans began to live longer. Most diseases were curable, and the overall quality of life improved. Surprisingly, the obsession with power and violence has led humanity to discover most of the essential technologies that are used in the modern world. Groundbreaking research in genetics has increased life expectancy as they attempt to achieve immortality.
