Yuval Noah Harari presents an outside view of humanity, from the perspective of a complete outsider, an alien with no particular interest in the human species. This is fascinating.

The scope of the book is very broad and often high level, starting with physics and chemistry 13.5 billion years ago at the dawn of the universe. Then, he turns to biology, which begins 3.8 billion years ago on earth, and finally to history and the cognitive revolution which starts about 70,000 years ago. Since then, 12,000 years ago, we had agriculture, which sped up the cognitive revolution. More recently, 500 years ago, the scientific revolution really turned it up a notch. The orders of magnitude of difference are appropriately humbling.

I liked the distinction between objective, subjective, and inter-subjective. The latter meaning something that exists within the communication network linking the subjective consciousness of many individuals. If a single individual changes his or her beliefs, or even dies, it is of little importance.

Also striking was Harari's disdain for the agricultural revolution. He claims that it made most people worse off. The general point being that "history's choices are not made for the benefit of humans".

Another major theme is the unification of humankind, which compounds inter-subjective effects since societies grow bigger and bigger. Over time, cultures coalesce and form bigger and more complex civilisations. Even though today's civilizations seem to be clashing, they actually agree on many things, for example money. "For thousands of years, philosophers, thinkers, and prophets have besmirched money and called it the root of all evil. Be that as it may, money is also the apogee of human tolerance."

On religion, Harari has insights as well:

So, monotheism explains order, but is mystified by evil. Dualism explains evil, but is puzzled by order. There is one logical way of solving the riddle: to argue that there is a single omnipotent God who created the entire universe - and He's evil. But nobody in history has had the stomach for such a belief.

Also, interestingly, he considers most "isms" to be religions. And this leads to interesting analyses. Harari delves deeply into humanism which he breaks down into three kinds:

1. Liberal humanism: that 'humanity' is a quality of individual humans, and that the liberty of individuals is therefore sacrosanct.
2. Socialist humanism: hold as sacred not the inner voice of each individual, but the species Homo sapiens as a whole.
3. Evolutionary humanism: humankind is not something universal and eternal, but rather a mutable species that can evolve or degenerate.

The latter has a long connection to Nazism, but Harari suggests (and I agree) that modern biology is really pushing us back into that vein.

On the scientific revolution, Harari echoes the rational sentiment of accepting ignorance. As soon as you truly accept that you do not know, you leave the door open to new insights.

The Scientific Revolution has not been a revolution of knowledge. It has been above all a revolution of ignorance. The great discovery that launched the Scientific Revolution was the discovery that humans do not know the answers to their most important questions.

Overall, very worth a read (or listen, as I did).